WorldWideScience

Sample records for show ovulatory defects

  1. Immature rats show ovulatory defects similar to those in adult rats lacking prostaglandin and progesterone actions

    Sanchez-Criado Jose E

    2004-09-01

    Full Text Available Abstract Gonadotropin-primed immature rats (GPIR constitute a widely used model for the study of ovulation. Although the equivalence between the ovulatory process in immature and adult rats is generally assumed, the morphological and functional characteristics of ovulation in immature rats have been scarcely considered. We describe herein the morphological aspects of the ovulatory process in GPIR and their response to classical ovulation inhibitors, such as the inhibitor of prostaglandin (PG synthesis indomethacin (INDO and a progesterone (P receptor (PR antagonist (RU486. Immature Wistar rats were primed with equine chorionic gonadotropin (eCG at 21, 23 or 25 days of age, injected with human chorionic gonadotropin (hCG 48 h later, and sacrificed 16 h after hCG treatment, to assess follicle rupture and ovulation. Surprisingly, GPIR showed age-related ovulatory defects close similar to those in adult rats lacking P and PG actions. Rats primed with eCG at 21 or 23 days of age showed abnormally ruptured corpora lutea in which the cumulus-oocyte complex (COC was trapped or had been released to the ovarian interstitum, invading the ovarian stroma and blood and lymphatic vessels. Supplementation of immature rats with exogenous P and/or PG of the E series did not significantly inhibit abnormal follicle rupture. Otherwise, ovulatory defects were practically absent in rats primed with eCG at 25 days of age. GPIR treated with INDO showed the same ovulatory alterations than vehicle-treated ones, although affecting to a higher proportion of follicles. Blocking P actions with RU486 increased the number of COC trapped inside corpora lutea and decreased ovulation. The presence of ovulatory defects in GPIR, suggests that the capacity of the immature ovary to undergo the coordinate changes leading to effective ovulation is not fully established in Wistar rats primed with eCG before 25 days of age.

  2. Cortical mechanics and myosin-II abnormalities associated with post-ovulatory aging: implications for functional defects in aged eggs

    Mackenzie, Amelia C.L.; Kyle, Diane D.; McGinnis, Lauren A.; Lee, Hyo J.; Aldana, Nathalia; Robinson, Douglas N.; Evans, Janice P.

    2016-01-01

    young eggs, by ∼40% in the cortical region where the metaphase II spindle is sequestered and by ∼50% in the domain to which sperm bind and fuse (P eggs with a zinc ionophore (P = 0.003), as is parthenogenesis induced by inhibition of mitogen-activated kinase (MAPK) 3/1 [also known as extracellular signal-regulated kinase (ERK)1/2] or MLCK. Inhibition of MLCK with ML-7 also results in effects that mimic those of post-ovulatory aging: fertilized ML-7-treated eggs show both impaired fertilization and increased extents of polyspermy, and ML-7-treated young eggs have several membrane abnormalities that are shared by post-ovulatory aged eggs. LIMITATIONS, REASONS FOR CAUTION These studies were done with mouse oocytes, and it remains to be fully determined how these findings from mouse oocytes would compare with other species. For studies using methods not amenable to analysis of large sample sizes and data are limited to what images one can capture (e.g. SEM), data should be interpreted conservatively. WIDER IMPLICATIONS OF THE FINDINGS These data provide insights into causes of reproductive failures at later post-copulatory times. LARGE SCALE DATA Not applicable. STUDY FUNDING AND COMPETING INTEREST(S) This project was supported by R01 HD037696 and R01 HD045671 from the NIH to J.P.E. Cortical tension studies were supported by R01 GM66817 to D.N.R. The authors declare there are no financial conflicts of interest. PMID:26921397

  3. Protein intake and ovulatory infertility.

    Chavarro, Jorge E; Rich-Edwards, Janet W; Rosner, Bernard A; Willett, Walter C

    2008-02-01

    The objective of the study was to evaluate whether intake of protein from animal and vegetable origin is associated with ovulatory infertility. A total of 18,555 married women without a history of infertility were followed up as they attempted a pregnancy or became pregnant during an 8 year period. Dietary assessments were related to the incidence of ovulatory infertility. During follow-up, 438 women reported ovulatory infertility. The multivariate-adjusted relative risk (RR) (95% confidence interval [CI]; P for trend) of ovulatory infertility comparing the highest to the lowest quintile of animal protein intake was 1.39 (1.01 to 1.90; 0.03). The corresponding RR (95% CI; P for trend) for vegetable protein intake was 0.78 (0.54 to 1.12; 0.07). Furthermore, consuming 5% of total energy intake as vegetable protein rather than as animal protein was associated with a more than 50% lower risk of ovulatory infertility (P =.007). Replacing animal sources of protein with vegetable sources of protein may reduce ovulatory infertility risk.

  4. An Mcm10 Mutant Defective in ssDNA Binding Shows Defects in DNA Replication Initiation.

    Perez-Arnaiz, Patricia; Kaplan, Daniel L

    2016-11-20

    Mcm10 is an essential protein that functions to initiate DNA replication after the formation of the replication fork helicase. In this manuscript, we identified a budding yeast Mcm10 mutant (Mcm10-m2,3,4) that is defective in DNA binding in vitro. Moreover, this Mcm10-m2,3,4 mutant does not stimulate the phosphorylation of Mcm2 by Dbf4-dependent kinase (DDK) in vitro. When we expressed wild-type levels of mcm10-m2,3,4 in budding yeast cells, we observed a severe growth defect and a substantially decreased DNA replication. We also observed a substantially reduced replication protein A- chromatin immunoprecipitation signal at origins of replication, reduced levels of DDK-phosphorylated Mcm2, and diminished Go, Ichi, Ni, and San (GINS) association with Mcm2-7 in vivo. mcm5-bob1 bypasses the growth defect conferred by DDK-phosphodead Mcm2 in budding yeast. However, the growth defect observed by expressing mcm10-m2,3,4 is not bypassed by the mcm5-bob1 mutation. Furthermore, origin melting and GINS association with Mcm2-7 are substantially decreased for cells expressing mcm10-m2,3,4 in the mcm5-bob1 background. Thus, the origin melting and GINS-Mcm2-7 interaction defects we observed for mcm10-m2,3,4 are not explained by decreased Mcm2 phosphorylation by DDK, since the defects persist in an mcm5-bob1 background. These data suggest that DNA binding by Mcm10 is essential for the initiation of DNA replication. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Women's health implications of ovulatory dysfunction

    Daan, NMP

    2016-01-01

    The association between ovulatory dysfunction and the occurrence of future CVD events remains largely unsettled.The association between PCOS and cardiometabolic abnormalities (e.g. obesity, dyslipidemia, insulin resistance) has indeed been clearly established, and was reaffirmed in the current

  6. Mutations in Caenorhabditis elegans him-19 show meiotic defects that worsen with age.

    Tang, Lois; Machacek, Thomas; Mamnun, Yasmine M; Penkner, Alexandra; Gloggnitzer, Jiradet; Wegrostek, Christina; Konrat, Robert; Jantsch, Michael F; Loidl, Josef; Jantsch, Verena

    2010-03-15

    From a screen for meiotic Caenorhabditis elegans mutants based on high incidence of males, we identified a novel gene, him-19, with multiple functions in prophase of meiosis I. Mutant him-19(jf6) animals show a reduction in pairing of homologous chromosomes and subsequent bivalent formation. Consistently, synaptonemal complex formation is spatially restricted and possibly involves nonhomologous chromosomes. Also, foci of the recombination protein RAD-51 occur delayed or cease altogether. Ultimately, mutation of him-19 leads to chromosome missegregation and reduced offspring viability. The observed defects suggest that HIM-19 is important for both homology recognition and formation of meiotic DNA double-strand breaks. It therefore seems to be engaged in an early meiotic event, resembling in this respect the regulator kinase CHK-2. Most astonishingly, him-19(jf6) hermaphrodites display worsening of phenotypes with increasing age, whereas defects are more severe in female than in male meiosis. This finding is consistent with depletion of a him-19-dependent factor during the production of oocytes. Further characterization of him-19 could contribute to our understanding of age-dependent meiotic defects in humans.

  7. Retinoblastoma pathway defects show differential ability to activate the constitutive DNA damage response in human tumorigenesis

    Tort, F.; Bartkova, J.; Sehested, M.

    2006-01-01

    culture models with differential defects of retinoblastoma pathway components, as overexpression of cyclin D1 or lack of p16(Ink4a), either alone or combined, did not elicit detectable DDR. In contrast, inactivation of pRb, the key component of the pathway, activated the DDR in cultured human or mouse...... with their hierarchical positions along the retinoblastoma pathway. Our data provide new insights into oncogene-evoked DDR in human tumorigenesis, with potential implications for individualized management of tumors with elevated cyclin D1 versus cyclin E, due to their distinct clinical variables and biological behavior....

  8. Correlation of Erythrocyte Trans Fatty Acids with Ovulatory Disorder Infertility in Polycystic Ovarian Syndrome

    Aisa Ghaffarzad

    2014-07-01

    Full Text Available Trans fatty acids are considered to be the important modifiable factor of the ovulatory infertility disorder. The purpose of this study was to test the hypothesis that higher trans fatty acids of erythrocytes (RBC are associated with the risk of ovulatory infertility disorder in polycystic ovarian syndrome (PCOS. Thirty five infertile women with polycystic ovarian syndrome, defined by AES criteria and 29 age-matched healthy women as a control group were recruited for the study. After physical measurements and nutritional assessment, blood samples were collected. Fasting serum glucose and insulin were measured, and then insulin resistance was calculated by homeostasis model assessment (HOMA-IR. Erythrocyte fatty acids were measured by gas chromatography. The patients group had higher waist circumference (WC, insulin levels, HOMA-IR than controls (p< 0.05. Also, case group had lower percentage of normal BMI (BMI<25, physical activity and education levels than healthy women (p< 0.05. Among RBC trans fatty acids only trans linoleate (18:2t were significantly higher in case group than control women (p= 0.019. PCOS group tended to consume more food rich in TFAs than the control group. Logistic regression analysis also showed that only 18:2t is positively associated with risk of ovulatory disorder infertility in PCOS (OR= 1.225, 95% CI. 1.024-1.465; P= 0.026, which was not affected after adjustment for BMI, physical activity and education levels. The results suggested that RBC trans fatty acids might be a predictor of increased risk for ovulatory infertility disorder in women with PCOS.

  9. Changes in women's attractiveness perception of masculine men's dances across the ovulatory cycle: preliminary data.

    Cappelle, Tessa; Fink, Bernhard

    2013-10-10

    Women's preferences for putative cues of genetic quality in men's voices, faces, bodies, and behavioral displays are stronger during the fertile phase of the ovulatory cycle. Here we show that ovulatory cycle-related changes in women's attractiveness perceptions of male features are also found with dance movements, especially those perceived as highly masculine. Dance movements of 79 British men were recorded with an optical motion-capture system whilst dancing to a basic rhythm. Virtual humanoid characters (avatars) were created and converted into 15-second video clips and rated by 37 women on masculinity. Another 23 women judged the attractiveness of the 10 dancers who scored highest and those 10 who scored lowest on masculinity once in days of high fertility and once in days of low fertility of their ovulatory cycle. High-masculine dancers were judged higher on attractiveness around ovulation than on other cycle days, whilst no such perceptual difference was found for low-masculine dancers. We suggest that women may gain fitness benefits from evolved preferences for masculinity cues they obtain from male dance movements.

  10. Changes in Women's Attractiveness Perception of Masculine Men's Dances across the Ovulatory Cycle: Preliminary Data

    Tessa Cappelle

    2013-07-01

    Full Text Available Women's preferences for putative cues of genetic quality in men's voices, faces, bodies, and behavioral displays are stronger during the fertile phase of the ovulatory cycle. Here we show that ovulatory cycle-related changes in women's attractiveness perceptions of male features are also found with dance movements, especially those perceived as highly masculine. Dance movements of 79 British men were recorded with an optical motion-capture system whilst dancing to a basic rhythm. Virtual humanoid characters (avatars were created and converted into 15-second video clips and rated by 37 women on masculinity. Another 23 women judged the attractiveness of the 10 dancers who scored highest and those 10 who scored lowest on masculinity once in days of high fertility and once in days of low fertility of their ovulatory cycle. High-masculine dancers were judged higher on attractiveness around ovulation than on other cycle days, whilst no such perceptual difference was found for low-masculine dancers. We suggest that women may gain fitness benefits from evolved preferences for masculinity cues they obtain from male dance movements.

  11. Seasonal ovulatory activity exists in tropical Creole female goats and Black Belly ewes subjected to a temperate photoperiod.

    Chemineau, Philippe; Daveau, Agnès; Cognié, Yves; Aumont, Gilles; Chesneau, Didier

    2004-08-27

    Seasonality of ovulatory activity is observed in European sheep and goat breeds, whereas tropical breeds show almost continuous ovulatory activity. It is not known if these tropical breeds are sensitive or not to temperate photoperiod. This study was therefore designed to determine whether tropical Creole goats and Black-Belly ewes are sensitive to temperate photoperiod. Two groups of adult females in each species, either progeny or directly born from imported embryos, were used and maintained in light-proof rooms under simulated temperate (8 to 16 h of light per day) or tropical (11 - 13 h) photoperiods. Ovulatory activity was determined by blood progesterone assays for more than two years. The experiment lasted 33 months in goats and 25 months in ewes. Marked seasonality of ovulatory activity appeared in the temperate group of Creole female goats. The percentage of female goats experiencing at least one ovulation per month dramatically decreased from May to September for the three years (0%, 27% and 0%, respectively). Tropical female goats demonstrated much less seasonality, as the percentage of goats experiencing at least one ovulation per month never went below 56%. These differences were significant. Both groups of temperate and tropical Black-Belly ewes experienced a marked seasonality in their ovulatory activity, with only a slightly significant difference between groups. The percentage of ewes experiencing at least one ovulation per month dropped dramatically in April and rose again in August (tropical ewes) or September (temperate ewes). The percentage of ewes experiencing at least one ovulation per month never went below 8% and 17% (for tropical and temperate ewes respectively) during the spring and summer months. An important seasonality in ovulatory activity of tropical Creole goats was observed when females were exposed to a simulated temperate photoperiod. An unexpected finding was that Black-Belly ewes and, to a lesser extent, Creole goats exposed to

  12. Obesity affects spontaneous pregnancy chances in subfertile, ovulatory women

    J.W. van der Steeg (Jan Willem); P. Steures (Pieternel); M.J.C. Eijkemans (René); J.D.F. Habbema (Dik); P.G. Hompes (Peter); J.M. Burggraaff (Jan); G.J.E. Oosterhuis (Jur); P.M.M. Bossuyt (Patrick); F. Veen (Fulco); B.W.J. Mol (Ben)

    2008-01-01

    textabstractBACKGROUND: Obesity is increasing rapidly among women all over the world. Obesity is a known risk factor for subfertility due to anovulation, but it is unknown whether obesity also affects spontaneous pregnancy chances in subfertile, ovulatory women. METHODS: We evaluated whether obesity

  13. Obesity affects spontaneous pregnancy chances in subfertile, ovulatory women

    van der Steeg, Jan Willem; Steures, Pieternel; Eijkemans, Marinus J. C.; Habbema, J. Dik F.; Hompes, Peter G. A.; Burggraaff, Jan M.; Oosterhuis, G. Jur E.; Bossuyt, Patrick M. M.; van der Veen, Fulco; Mol, Ben W. J.

    2008-01-01

    BACKGROUND: Obesity is increasing rapidly among women all over the world. Obesity is a known risk factor for subfertility due to anovulation, but it is unknown whether obesity also affects spontaneous pregnancy chances in subfertile, ovulatory women. METHODS: We evaluated whether obesity affected

  14. Ovulatory Follicular Dynamics After Estrus Synchronization using Prostaglandin F2a in Dairy Cows

    Prabowo Purwono Putro

    2014-11-01

    Full Text Available The study aimed to follow development of ovulatory follicular dynamics as well as plasma progesterone profile after estrus synchronization using PGF2 and GnRH.   A total of 15 non-pregnant dairy cows, 4-5 years of age, healthy and reproductively sound were used in the present study.     Treatment 1, given intramuscular injection of PGF2 25 mg (PGF2, treatment 2 PGF2 25 mg and GnRH 250 g 2 days later (PGF2-GnRH, and treatment 3 with GnRH 250 g (7 days prior to injection of PGF2, PGF2 25 mg and GnRH 250 g (2 days after injection of PGF2  (GnRH-PGF2a-GnRH (the Ovsynch method.   Transrectal ultrasonographic examination using real time, B-mode, with 7.5 MHz tranducer was performed everyday for 12 days to follow ovulatory follicular and luteal dynamics.   Blood plasma was taken every day for progesterone determination using EIA technique.   Data of follicular, luteal development and progesterone levels were tested using analysis of variance and correlation analysis.   The animals showed estrus within 70.70 + 01.90 hours following PGF2 injection.   Prostaglandin F2 induced corpus luteum regression, decreased  in progesterone plasma levels, followed by ovulatory follicular development and eventually underwent ovulation.   Administration of first GnRH increased corpus luteum size, enhanced its regression and decreased plasma progesterone levels, while  the second administration induce  better ovulatory follicular development.   Rate of the corpus luteum regression, progesterone decrease and ovulatory follicular development following PGF2 injection for respective treatments 1, 2 and 3 were 2.53 + 0.24a, 2.73 + 0.36a and 3.53 + 0.28b mm/day; 1.39 + 0.14a,  1.35 + 0.18a dan 1.57 + 0.12b ng/ml/day; and 1.33 + 0.15a,  1.63 + 0.19b and 1.67 + 0.23b mm/day, respectively (P < 0.05.   It can be concluded that PGF2 induced corpus luteum regression, decreased in  progesterone plasma

  15. Color Doppler imaging and measurements of intraovarian and intrauterine vascularization on basal ultrasound examination in spontaneous ovulatory and anovulatory cycles

    Kutlešić Ranko

    2008-01-01

    Full Text Available Background/Aim. Any organs functioning directly depends on vascularization. It applies also to the uterus and ovary which go through changes of vascularization during a menstruation cycle. The aim of this investigation was to determine differences in intrauterine and ovarian stromal arterioral blood flow on basal ultrasound examination (day 2-4 between spontaneous ovulatory and anovulatory cycles. Methods. This prospective clinical investigation included 205 patients divided into two groups: with ovulatory and with anovulatory cycles. Results. Resistance to ovarian arterioral stromal blood flow was significantly lower in the patients with ovulatory cycles (pulsatile index - PI 0.97 ± 0.4 vs 1.93 ± 1.37; p = 0.001737; and (resistance index - RI 0.55 ± 0.12 vs 0.68 ± 0.14; p = 0.040033. There were no statistically significant differences in arcuate arterioral blood flow in the pateints with ovulatory and anovulatory cycles (PI 1.21 ± 0.34 vs 61 ± 0,61 p = 0.136161 and RI 0.64 ± 0.11 vs 0.74 ± 0.07; p = 0.136649. The patients with ovulatory cycles had lower uterine radial arterioral blood flow than the patients with anovulatory cycles (PI 1.001 ± 0.22 vs 1.61 ± 0.23 p = 0.007501 and RI 0.55 ± 0.08 vs 0.71 ± 0.12; p = 0,0460113. The patients with ovulatory cycles had lower subendometrial arterioral blood flow resistance (PI 0.69 ± 0.19 vs 1.385±0.09; p = 0.00622 and RI 0.44 ± 0.09 vs 0.65 ± 0.02; p = 0.027458. Conclusion. Color Doppler ultrasuond imaging and measurements of intrauterine and ovarian stromal arterioral blood flow on basal ultrasound examination (day 2-4, showed lower resistance to blood flow in ovulatory than in anovulatory cycles.

  16. Do NiTi instruments show defects before separation? Defects caused by torsional fatigue in hand and rotary nickel-titanium (NiTi) instruments which lead to failure during clinical use.

    Chakka, N V Murali Krishna; Ratnakar, P; Das, Sanjib; Bagchi, Anandamy; Sudhir, Sudhir; Anumula, Lavanya

    2012-11-01

    Visual and microscopic evaluation of defects caused by torsional fatigue in hand and rotary nickel titanium (NiTi) instruments. Ninety-six NiTi greater taper instruments which were routinely used for root canal treatment only in anterior teeth were selected for the study. The files taken include ProTaper for hand use, ProTaper Rotary files and Endowave rotary files. After every use, the files were observed visually and microscopically (Stereomicroscope at 10×) to evaluate the defects caused by torsional fatigue. Scoring was given according to a new classification formulated which gives an indication of the severity of the defect or damage. Data was statistically analyzed using KruskallWallis and Mann-Whitney U test. Number of files showing defects were more under stereomicroscope than visual examination. But, the difference in the evaluation methods was not statistically significant. The different types of defects observed were bent instrument, straightening/stretching of twist contour and partial reverse twisting. Endowave files showed maximum number of defects followed by ProTaper for hand use and least in ProTaper Rotary. Visible defects due to torsional fatigue do occur in NiTi instruments after clinical use. Both visual and microscopic examinations were efficient in detecting defects caused due to torsional fatigue. This study emphasizes that all files should be observed for any visible defects before and after every instrumentation cycle to minimize the risk of instrument separation and failure of endodontic therapy.

  17. Arabidopsis thaliana plants lacking the ARP2/3 complex show defects in cell wall assembly and auxin distribution.

    Pratap Sahi, Vaidurya; Cifrová, Petra; García-González, Judith; Kotannal Baby, Innu; Mouillé, Gregory; Gineau, Emilie; Müller, Karel; Baluška, František; Soukup, Aleš; Petrášek, Jan; Schwarzerová, Katerina

    2017-12-25

    The cytoskeleton plays an important role in the synthesis of plant cell walls. Both microtubules and actin cytoskeleton are known to be involved in the morphogenesis of plant cells through their role in cell wall building. The role of ARP2/3-nucleated actin cytoskeleton in the morphogenesis of cotyledon pavement cells has been described before. Seedlings of Arabidopsis mutants lacking a functional ARP2/3 complex display specific cell wall-associated defects. In three independent Arabidopsis mutant lines lacking subunits of the ARP2/3 complex, phenotypes associated with the loss of the complex were analysed throughout plant development. Organ size and anatomy, cell wall composition, and auxin distribution were investigated. ARP2/3-related phenotype is associated with changes in cell wall composition, and the phenotype is manifested especially in mature tissues. Cell walls of mature plants contain less cellulose and a higher amount of homogalacturonan, and display changes in cell wall lignification. Vascular bundles of mutant inflorescence stems show a changed pattern of AUX1-YFP expression. Plants lacking a functional ARP2/3 complex have decreased basipetal auxin transport. The results suggest that the ARP2/3 complex has a morphogenetic function related to cell wall synthesis and auxin transport. © The Author(s) 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Oxygen vacancy defects in Ta{sub 2}O{sub 5} showing long-range atomic re-arrangements

    Guo, Yuzheng; Robertson, John [Engineering Department, Cambridge University, Cambridge CB2 1PZ (United Kingdom)

    2014-03-17

    The structure, formation energy, and energy levels of the various oxygen vacancies in Ta{sub 2}O{sub 5} have been calculated using the λ phase model. The intra-layer vacancies give rise to unusual, long-range bonding rearrangements, which are different for each defect charge state. The 2-fold coordinated intra-layer vacancy is the lowest cost vacancy and forms a deep level 1.5 eV below the conduction band edge. The 3-fold intra-layer vacancy and the 2-fold inter-layer vacancy are higher cost defects, and form shallower levels. The unusual bonding rearrangements lead to low oxygen migration barriers, which are useful for resistive random access memory applications.

  19. The fluctuating female vote: politics, religion, and the ovulatory cycle.

    Durante, Kristina M; Rae, Ashley; Griskevicius, Vladas

    2013-06-01

    Each month, many women experience an ovulatory cycle that regulates fertility. Although research has found that this cycle influences women's mating preferences, we proposed that it might also change women's political and religious views. Building on theory suggesting that political and religious orientation are linked to reproductive goals, we tested how fertility influenced women's politics, religiosity, and voting in the 2012 U.S. presidential election. In two studies with large and diverse samples, ovulation had drastically different effects on single women and women in committed relationships. Ovulation led single women to become more liberal, less religious, and more likely to vote for Barack Obama. In contrast, ovulation led women in committed relationships to become more conservative, more religious, and more likely to vote for Mitt Romney. In addition, ovulation-induced changes in political orientation mediated women's voting behavior. Overall, the ovulatory cycle not only influences women's politics but also appears to do so differently for single women than for women in relationships.

  20. A Novel Expression Cassette of Lyssavirus Shows that the Distantly Related Mokola Virus Can Rescue a Defective Rabies Virus Genome

    Le Mercier, Philippe; Jacob, Yves; Tanner, Kyle; Tordo, Noël

    2002-01-01

    By comparing three expression vectors for the rabies virus (Rv) minigenome, we show that the characteristic of the Rv RNA is important for efficient rescue despite its not being crucial for replication. Moreover, we show that the coexpression of the viral proteins from helper Rv and Mokola virus could rescue the Rv minigenome while Rv-related European bat lyssavirus 1 could not, suggesting that the signals controlling transcription and replication are conserved in the distantly related Rv and Mokola virus. PMID:11799201

  1. A fasciclin-like arabinogalactan-protein (FLA mutant of Arabidopsis thaliana, fla1, shows defects in shoot regeneration.

    Kim L Johnson

    Full Text Available BACKGROUND: The fasciclin-like arabinogalactan-proteins (FLAs are an enigmatic class of 21 members within the larger family of arabinogalactan-proteins (AGPs in Arabidopsis thaliana. Located at the cell surface, in the cell wall/plasma membrane, they are implicated in many developmental roles yet their function remains largely undefined. Fasciclin (FAS domains are putative cell-adhesion domains found in extracellular matrix proteins of organisms from all kingdoms, but the juxtaposition of FAS domains with highly glycosylated AGP domains is unique to plants. Recent studies have started to elucidate the role of FLAs in Arabidopsis development. FLAs containing a single FAS domain are important for the integrity and elasticity of the plant cell wall matrix (FLA11 and FLA12 and FLA3 is involved in microspore development. FLA4/SOS5 with two FAS domains and two AGP domains has a role in maintaining proper cell expansion under salt stressed conditions. The role of other FLAs remains to be uncovered. METHOD/PRINCIPAL FINDINGS: Here we describe the characterisation of a T-DNA insertion mutant in the FLA1 gene (At5g55730. Under standard growth conditions fla1-1 mutants have no obvious phenotype. Based on gene expression studies, a putative role for FLA1 in callus induction was investigated and revealed that fla1-1 has a reduced ability to regenerate shoots in an in vitro shoot-induction assay. Analysis of FLA1p:GUS reporter lines show that FLA1 is expressed in several tissues including stomata, trichomes, the vasculature of leaves, the primary root tip and in lateral roots near the junction of the primary root. CONCLUSION: The results of the developmental expression of FLA1 and characterisation of the fla1 mutant support a role for FLA1 in the early events of lateral root development and shoot development in tissue culture, prior to cell-type specification.

  2. Radioimmunoassay method for measurement of plasma androstenedione. Its validation in ovulatory women and in patients with polycystic ovarian syndrome

    Vilanova Socorro Veras, Maria do; Silva e Rosa, Alzira Amelia; Moura, Marcos Dias de; Ferriano, Rui Alberto; Sa, Marcos Felipe Silva de

    1995-01-01

    The present paper has as objective the standardization of a radioimmunoassay method for measurement of androstenedione. Ethyl ether was used for plasma extraction. The sensitivity of the method was 6,8 pg/tube; the reproducibility (inter assay error) was 15,6%; the precision (intrassay error) was 5,2%. As biological control, 20 ovulatory women showed median plasma values of 1250 pg/ml and 24 women with polycystic ovary syndrome presented median plasma values of 2.037 pg/ml. (author). 6 refs., 2 figs., 1 tab

  3. Developmental programming: deficits in reproductive hormone dynamics and ovulatory outcomes in prenatal, testosterone-treated sheep.

    Veiga-Lopez, A; Ye, W; Phillips, D J; Herkimer, C; Knight, P G; Padmanabhan, V

    2008-04-01

    Prenatal testosterone excess leads to neuroendocrine, ovarian, and metabolic disruptions, culminating in reproductive phenotypes mimicking that of women with polycystic ovary syndrome (PCOS). The objective of this study was to determine the consequences of prenatal testosterone treatment on periovulatory hormonal dynamics and ovulatory outcomes. To generate prenatal testosterone-treated females, pregnant sheep were injected intramuscularly (days 30-90 of gestation, term=147 days) with 100 mg of testosterone-propionate in cottonseed oil semi-weekly. Female offspring born to untreated control females and prenatal testosterone-treated females were then studied during their first two breeding seasons. Sheep were given two injections of prostaglandin F2alpha 11 days apart, and blood samples were collected at 2-h intervals for 120 h, 10-min intervals for 8 h during the luteal phase (first breeding season only), and daily for an additional 15 days to characterize changes in reproductive hormonal dynamics. During the first breeding season, prenatal testosterone-treated females manifested disruptions in the timing and magnitude of primary gonadotropin surges, luteal defects, and reduced responsiveness to progesterone negative feedback. Disruptions in the periovulatory sequence of events during the second breeding season included: 1) delayed but increased preovulatory estradiol rise, 2) delayed and severely reduced primary gonadotropin surge in prenatal testosterone-treated females having an LH surge, 3) tendency for an amplified secondary FSH surge and a shift in the relative balance of FSH regulatory proteins, and 4) luteal responses that ranged from normal to anovulatory. These outcomes are likely to be of relevance to developmental origin of infertility disorders and suggest that differences in fetal exposure or fetal susceptibility to testosterone may account for the variability in reproductive phenotypes.

  4. Exposure of Lactating Dairy Cows to Acute Pre-Ovulatory Heat Stress Affects Granulosa Cell-Specific Gene Expression Profiles in Dominant Follicles

    Vanselow, Jens; Vernunft, Andreas; Koczan, Dirk; Spitschak, Marion; Kuhla, Björn

    2016-01-01

    High environmental temperatures induce detrimental effects on various reproductive processes in cattle. According to the predicted global warming the number of days with unfavorable ambient temperatures will further increase. The objective of this study was to investigate effects of acute heat stress during the late pre-ovulatory phase on morphological, physiological and molecular parameters of dominant follicles in cycling cows during lactation. Eight German Holstein cows in established lactation were exposed to heat stress (28°C) or thermoneutral conditions (15°C) with pair-feeding for four days. After hormonal heat induction growth of the respective dominant follicles was monitored by ultrasonography for two days, then an ovulatory GnRH dose was given and follicular steroid hormones and granulosa cell-specific gene expression profiles were determined 23 hrs thereafter. The data showed that the pre-ovulatory growth of dominant follicles and the estradiol, but not the progesterone concentrations tended to be slightly affected. mRNA microarray and hierarchical cluster analysis revealed distinct expression profiles in granulosa cells derived from heat stressed compared to pair-fed animals. Among the 255 affected genes heatstress-, stress- or apoptosis associated genes were not present. But instead, we found up-regulation of genes essentially involved in G-protein coupled signaling pathways, extracellular matrix composition, and several members of the solute carrier family as well as up-regulation of FST encoding follistatin. In summary, the data of the present study show that acute pre-ovulatory heat stress can specifically alter gene expression profiles in granulosa cells, however without inducing stress related genes and pathways and suggestively can impair follicular growth due to affecting the activin-inhibin-follistatin system. PMID:27532452

  5. Characteristics of infertile patients with ovulatory dysfunction and their relation to body mass index

    Sadia, S.; Waqar, F.; Akhtar, T.; Sultana, S.

    2009-01-01

    Ovulatory dysfunction is a group of disorders with variable clinical presentations occasionally having serious long-term adverse effects. It accounts for 30% of female fertility problems. Evidence suggests an association between an individual's weight and disorders of ovulation. The objective of our study was to describe the clinical and hormonal profile of subfertile women with ovulatory dysfunction in relation to their body mass index (BMI). Methods: This prospective, descriptive study was carried out in Mother and Child Health Centre, PIMS, Islamabad and Railway hospital, Rawalpindi from April 2001 to March 2007. One hundred and thirty eight infertile patients with ovulatory dysfunction were included. The clinical data including BMI of each patient was recorded in addition to reports of investigations comprised of cervical smear, pelvic ultrasound and hormonal profile. Results: Primary infertility was found in 61% while secondary in 39% of the patients. The mean age was 29 years and mean duration of infertility was 6 years. Menstrual pattern was normal in 56.5%. BMI was normal in 30.4% while most patients were overweight and obese. Prolonged cycles, history of systemic endocrine disorders, abnormal vaginal discharge, hirsutism, polycystic ovarian morphology and hormonal abnormalities were more frequent in patients with increased BMI. During the study period, 21.7% of the women conceived. Conclusion: Infertile patients with ovulatory dysfunction present more frequently with primary infertility. They usually have higher than required BMI. Oligomenorrhoea amenorrhoea, hirsutism and hormonal abnormalities are more frequent in overweight than infertile patients with ovulatory dysfunction having a normal BMI. (author)

  6. Growth rate of ovulatory follicles during the first ovulatory oestrus (after seasonal anoestrus) and subsequent oestrous period in Irish Draught mares.

    Newcombe, John R; Cuervo-Arango, Juan

    2013-03-12

    It is believed that during the spring transition, the developing follicle tends to grow more slowly, persist longer and grow to a larger diameter prior to ovulation than at subsequent oestrus periods. A general suspicion, that the first ovulation of the year is less fertile than subsequent ovulations could be explained by a slower growth rate of the ovulatory follicle during transition with the consequent production of a subfertile oocyte. By detailed serial examination of the same group of Irish Draught mares over three winter/spring periods, no significant difference was found in either growth rate or pre-ovulatory diameter when compared with subsequent ovulations. Mean growth rates over the ten days prior to ovulation were 2.20 mm/day (range 1.18 to 3.64) and 2.19 mm/day (range 1.25 to 3.41) for first and subsequent ovulations respectively. Mean maximum pre-ovulatory diameters were 44.7 mm (range 35 to 59) and 43.5 mm (range 31 to 57.5) for first and subsequent ovulations respectively. The impression gained by practitioners that the first follicle develops more slowly during the transition to the first ovulation of the season may be due to less frequent examinations and consequently a failure to observe and record that follicles may grow and then regress during this period. The largest follicle observed a few days previously is not necessarily the same large follicle found at a later examination.

  7. Using a Cyclical Diagram to Visualize the Events of the Ovulatory Menstrual Cycle

    Ho, Ivan Shun; Parmar, Navneet K.

    2014-01-01

    Over the past 10 years, college textbooks in human anatomy and physiology have typically presented the events of the ovulatory menstrual cycle in a linear format, with time in days shown on the x-axis, and hormone levels, follicular development, and uterine lining on the y-axis. In addition, the various events are often shown over a 28-day cycle,…

  8. Ovulatory disorders are an independent risk factor for pregnancy complications in women receiving assisted reproduction treatments.

    Barua, Sumita; Hng, Tien-Ming; Smith, Howard; Bradford, Jennifer; McLean, Mark

    2017-06-01

    Conception using assisted reproduction treatments (ART) has been associated with an increased risk of pregnancy complications. It is uncertain if this is caused by ART directly, or is an association of the underlying factors causing infertility. We assessed the relationship between assisted conception (AC) and maternal or fetal complications in a large retrospective cohort study. In a nested cohort of women receiving infertility treatment, we determined if such risk rests predominantly with certain causes of infertility. Retrospective database analysis of 50 381 women delivering a singleton pregnancy in four public hospital obstetric units in western Sydney, and a nested cohort of 508 women receiving ART at a single fertility centre, in whom the cause of infertility was known. A total of 1727 pregnancies followed AC; 48 654 were spontaneous conceptions. Adjusted for age, body mass index and smoking, AC was associated with increased risk of preterm delivery (OR 1.73, 95% CI 1.50-2.02), hypertension (OR 1.55, 95% CI 1.34-1.82) and diabetes (OR 1.51, 95% CI 1.30-1.75). In the nested cohort, ovulatory dysfunction was present in 145 women and 336 had infertility despite normal ovulatory function. Ovulatory dysfunction was associated with increased risk of diabetes (OR 2.94, 95% CI 1.72-5.02) and hypertension (OR 2.40, 95% CI 1.15-5.00) compared to women with normal ovulatory function. Assisted conception is associated with increased risk of pregnancy complications. This risk appears greatest for women whose underlying infertility involves ovulatory dysfunction. Such disorders probably predispose towards diabetes and hypertension, which is then exacerbated by pregnancy. © 2016 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.

  9. (3) Melatonin Protects Oocytes and Granulosa Cells from Reactive Oxygen Species during the Ovulatory Process

    田村, 博史; Hiroshi, TAMURA; 山口大学大学院医学系研究科産科婦人科学; Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine

    2009-01-01

    Reactive oxygen species (ROS) are produced within the follicle especially during the ovulatory process. ROS play a physiological role in the process of ovulation, e.g. follicle rapture. However, excessive amount of ROS causes oxidative stress and damages oocytes and luteinized granulosa cells. On the other hand, antioxidant defense systems including superoxide dismutase (SOD) or glutathione (GSH) are present in follicles. The balance between ROS and antioxidants within the follicle seems to b...

  10. Kidney-differentiated cells derived from Lowe Syndrome patient's iPSCs show ciliogenesis defects and Six2 retention at the Golgi complex.

    Wen-Chieh Hsieh

    Full Text Available Lowe syndrome is an X-linked condition characterized by congenital cataracts, neurological abnormalities and kidney malfunction. This lethal disease is caused by mutations in the OCRL1 gene, which encodes for the phosphatidylinositol 5-phosphatase Ocrl1. While in the past decade we witnessed substantial progress in the identification and characterization of LS patient cellular phenotypes, many of these studies have been performed in knocked-down cell lines or patient's cells from accessible cell types such as skin fibroblasts, and not from the organs affected. This is partially due to the limited accessibility of patient cells from eyes, brain and kidneys. Here we report the preparation of induced pluripotent stem cells (iPSCs from patient skin fibroblasts and their reprogramming into kidney cells. These reprogrammed kidney cells displayed primary cilia assembly defects similar to those described previously in cell lines. Additionally, the transcription factor and cap mesenchyme marker Six2 was substantially retained in the Golgi complex and the functional nuclear-localized fraction was reduced. These results were confirmed using different batches of differentiated cells from different iPSC colonies and by the use of the human proximal tubule kidney cell line HK2. Indeed, OCRL1 KO led to both ciliogenesis defects and Six2 retention in the Golgi complex. In agreement with Six2's role in the suppression of ductal kidney lineages, cells from this pedigree were over-represented among patient kidney-reprogrammed cells. We speculate that this diminished efficacy to produce cap mesenchyme cells would cause LS patients to have difficulties in replenishing senescent or damaged cells derived from this lineage, particularly proximal tubule cells, leading to pathological scenarios such as tubular atrophy.

  11. Factors affecting the size of ovulatory follicles and conception rate in high-yielding dairy cows.

    Mokhtari, A; Kafi, M; Zamiri, M J; Akbari, R

    2016-03-01

    Two studies were designed to determine (1) the effects of Heatsynch and Ovsynch protocols versus spontaneous ovulation and (2) the effects of calving problems, clinical uterine infections, and clinical mastitis on the size of the ovulatory follicle, conception rate, and embryonic/fetal (E/F) death in high-yielding dairy cows. In study 1, cows without the history of calving problems, clinical uterine infections, and clinical mastitis were randomly allocated to either an Ovsynch (n = 45) or Heatsynch (n = 39) ovulation synchronization protocol or spontaneous ovulation (n = 43) groups. Blood samples were collected on the day of artificial insemination (AI) to measure progesterone (P4), estradiol-17β, and insulin-like growth factor 1 (IGF-1) and 7 days later to measure P4. Study 2 consisted of cows (n = 351) with or without the history of calving problems, clinical uterine infections, and clinical mastitis which were artificially inseminated after a 55-day voluntary waiting period. Transrectal ultrasonography was performed at the time of AI to measure the ovulatory follicle size and on Days 30 and 68 after AI to diagnose pregnancy in both studies. In study 1, the mean (±standard error of the mean) diameter of the ovulatory follicle was greater (P = 0.0005) and E/F mortality was lower (P = 0.007) for the spontaneous ovulation group compared with Ovsynch and Heatsynch groups. Serum concentration of P4 on Day 7 after AI was correlated with the size of the ovulatory follicle (P = 0.007). Conception rate at Days 30 and 68 was not significantly different between the three experimental groups in study 1. Cows with serum IGF-1 concentrations greater than 55 ng/mL at AI had significantly higher Day 68 conception rate (50% vs. 24%) and lower E/F death (16.6% vs. 40%) compared to cows with serum IGF-1 concentrations lower than 56 ng/mL at AI. The conception rate on Days 30 and 68 for follicles of 10 to 14 mm in diameter (34% and 21.8%) was significantly lower than follicles of

  12. The influence of sporadic anovulation on hormone levels in ovulatory cycles

    Hambridge, H.L.; Mumford, S.L.; Mattison, D.R.; Ye, A.; Pollack, A.Z.; Bloom, M.S.; Mendola, P.; Lynch, K.L.; Wactawski-Wende, J.; Schisterman, E.F.

    2013-01-01

    STUDY QUESTION Do ovulatory hormone profiles among healthy premenopausal women differ between women with and without sporadic anovulation? SUMMARY ANSWER Women with one anovulatory cycle tended to have lower estradiol, progesterone and LH peak levels during their ovulatory cycle. WHAT IS KNOWN ALREADY Anovulation occurs sporadically in healthy premenopausal women, but the influence of hormones in a preceding cycle and the impact on a subsequent cycle's hormone levels is unknown. STUDY DESIGN, SIZE, DURATION The BioCycle Study was a prospective cohort including 250 healthy regularly menstruating women, 18–44 years of age, from Western New York with no history of menstrual or ovulation disorders. The women were followed with up to eight study visits per cycle for two cycles, most of which were consecutive. PARTICIPANTS/MATERIALS, SETTING AND METHODS All study visits were timed to menstrual cycle phase using fertility monitors and located at the University at Buffalo women's health research center from 2005 to 2007. The main outcomes measured were estradiol, progesterone, LH and follicle-stimulating hormone levels in serum at up to 16 visits over two cycles. Anovulation was defined as peak serum progesterone concentrations ≤5 ng/ml and no serum LH peak detected during the mid- or late-luteal phase visit. MAIN RESULTS AND THE ROLE OF CHANCE Reproductive hormone concentrations were lower during anovulatory cycles, but significant reductions were also observed in estradiol (−25%, P = 0.003) and progesterone (−22%, P = 0.001) during the ovulatory cycles of women with one anovulatory cycle compared with women with two ovulatory cycles. LH peak concentrations were decreased in the ovulatory cycle of women with an anovulatory cycle (significant amplitude effect, P = 0.004; geometric mean levels 38% lower, P cycles, and no ultrasound assessment of ovulation was available. Data were missing for a total of 168 of a possible 4072 cycle visits (4.1%), though all women had

  13. Body condition and stage of seasonal anestrus interact to determine the ovulatory response after male biostimulation in anovulatory Criollo × Nubian goats.

    Vera-Avila, Hector R; Urrutia-Morales, Jorge; Espinosa-Martinez, Mario A; Gamez-Vazquez, Hector G; Jimenez-Severiano, Hector; Villagomez-Amezcua, Eugenio

    2017-06-01

    The effect of goat nutritional condition on the response to biostimulation with sexually active males during different stages of anestrus was determined. Fifty-eight Criollo × Nubian females on high and low body mass index (BMI) diets were used. Each BMI group was divided into two for biostimulation with sexually active males during May (mid-anestrus) or July (transition period). Ovulatory responses to biostimulation were characterized from serum progesterone, as well as the delay for response (first and second ovulations followed by a normal length luteal phase, O-WNLP). The percentage of goats showing one O-WNLP was greater in the high BMI group than in the low BMI group and greater during the transition period than in the mid-anestrus. However, the interaction between factors revealed that the difference between BMI groups was only significant in the transition period and the difference between stages was only significant in goats with high BMI. Occurrence of a second O-WNLP tended to be greater in the high BMI group than in the low BMI group. Response delay was shorter in the transition period than in mid-anestrus. In conclusion, female nutritional status interacting with the stage of anestrus determined the ovulatory response to male biostimulation in crossbred Criollo goats. © 2016 Japanese Society of Animal Science.

  14. [Features of Professor Ma Kun's medication in treating ovulatory infertility].

    Tong, Ya-Jing; Zhang, Hui-Xian; Chen, Yan-Xia; Dong, Mei-Ling; Ma, Kun

    2017-12-01

    In order to analyze Professor Ma Kun's medication in treating anovulatory infertility, her prescriptions for treating anovulatory infertility in 2012-2015 were collected. The medication features and the regularity of prescriptions were mined by using traditional Chinese medicine inheritance support system, association rules, complex system entropy clustering and other mining methods. Finally, a total of 684 prescriptions and 300 kinds of herbs were screened out, with a total frequency of 11 156 times; And 68 core combinations and 8 new prescriptions were mined. The top three frequently used herbs by effect were respectively tonic herb, blood circulation promoting herb, and Qi-circulation promoting herb. The top three tastes were sweetness, bitterness and pungent flavor. The results showed 28 herbs with a high frequency of ≥100.The top 10 frequently used herbs were respectively Angelica Sinensis Radix, Cyperi Rhizoma, Chuanxiong Rhizome, Paeoniae Radix Rubra, Cyathulae Radix, Taxilli Herba, Cuscutae Semen, Codonopsis Radix, Ligustri Lucidi Fructus, Paeoniae Albaand Paeoniae Radix Alba. The association rules analysis showed commonly used herbal pairs, including Rehmanniae Radix Preparata-Chuanxiong Rhizome, Rehmanniae Radix Preparata-Angelica Sinensis Radix, Cuscutae Semen-Dipsaci Radix. In conclusion, Professor Ma has treated anovulatory infertility by nourishing the kidney and activating blood throughout the treatment course, and attached the importance to the relationship between Qi and blood and there gulation of liver, spleen and kidney in treating anovulatory infertility. Copyright© by the Chinese Pharmaceutical Association.

  15. Coordinated Regulation Among Progesterone, Prostaglandins, and EGF-Like Factors in Human Ovulatory Follicles.

    Choi, Yohan; Wilson, Kalin; Hannon, Patrick R; Rosewell, Katherine L; Brännström, Mats; Akin, James W; Curry, Thomas E; Jo, Misung

    2017-06-01

    In animal models, the luteinizing hormone surge increases progesterone (P4) and progesterone receptor (PGR), prostaglandins (PTGs), and epidermal growth factor (EGF)-like factors that play essential roles in ovulation. However, little is known about the expression, regulation, and function of these key ovulatory mediators in humans. To determine when and how these key ovulatory mediators are induced after the luteinizing hormone surge in human ovaries. Timed periovulatory follicles were obtained from cycling women. Granulosa/lutein cells were collected from in vitro fertilization patients. The in vivo and in vitro expression of PGR, PTG synthases and transporters, and EGF-like factors were examined at the level of messenger RNA and protein. PGR binding to specific genes was assessed. P4 and PTGs in conditioned media were measured. PGR, PTGS2, and AREG expressions dramatically increased in ovulatory follicles at 12 to 18 hours after human chorionic gonadotropin (hCG). In human granulosa/lutein cell cultures, hCG increased P4 and PTG production and the expression of PGR, specific PTG synthases and transporters, and EGF-like factors, mimicking in vivo expression patterns. Inhibitors for P4/PGR and EGF-signaling pathways reduced hCG-induced increases in PTG production and the expression of EGF-like factors. PGR bound to the PTGS2, PTGES, and SLCO2A1 genes. This report demonstrated the time-dependent induction of PGR, AREG, and PTGS2 in human periovulatory follicles. In vitro studies indicated that collaborative actions of P4/PGR and EGF signaling are required for hCG-induced increases in PTG production and potentiation of EGF signaling in human periovulatory granulosa cells. Copyright © 2017 Endocrine Society

  16. Multiparameter Investigation of a 46,XX/46,XY Tetragametic Chimeric Phenotypical Male Patient with Bilateral Scrotal Ovotestes and Ovulatory Activity.

    van Bever, Yolande; Wolffenbuttel, Katja P; Brüggenwirth, Hennie T; Blom, Eric; de Klein, Annelies; Eussen, Bert H J; van der Windt, Florijn; Hannema, Sabine E; Dessens, Arianne B; Dorssers, Lambert C J; Biermann, Katharina; Hersmus, Remko; de Rijke, Yolanda B; Looijenga, Leendert H J

    2018-01-01

    We report on an adult male initially presenting with gynecomastia and a painless scrotal mass without additional genital anomalies. Hyperpigmentation of the skin following the Blaschko's lines was identified. He underwent gonadectomy because of suspected cancer. Histological analyses revealed an ovotestis with ovulatory activity confirmed by immunohistochemistry with multiple markers. Karyotyping of cultured peripheral blood lymphocytes and a buccal smear revealed a 46,XX/46,XY chimeric constitution with different percentages. Multiple molecular analyses as well as blood typing implied a tetragametic origin. After the unilateral gonadectomy, the patient developed recurrent painful cystic swellings of the remaining gonad. Because of the wish to preserve hormonal activity as well as future fertility, the patient underwent surgical resection of a cystic gonadal area. The removed tissue showed ovulation-related features in addition to both testicular and ovarian tissue, diagnosed as an ovotestis. Testosterone therapy was initiated to suppress the persistently elevated gonadotropins and thereby suppress ovarian activity. During treatment, the recurrent pain complaints and cystic swellings ceased, although gonadotropin levels were not fully suppressed. Based on these observations, the importance of a detailed genetic and pathological diagnosis and the clinical dilemmas including the pros and cons of personalized treatment with gonadal preservative surgery are discussed. © 2017 S. Karger AG, Basel.

  17. Surface plasmon resonance analysis shows an IgG-isotype-specific defect in ABO blood group antibody formation in patients with common variable immunodeficiency

    Michael Bernhard Fischer

    2015-05-01

    Full Text Available Background: Common variable immunodeficiency (CVID is the most common clinically severe primary immunodeficiency and comprises a heterogeneous group of patients with recurrent severe bacterial infections due to the failure to produce IgG antibodies after exposure to infectious agents and immunization. Diagnostic recommendations for antibody failure include assessment of isoagglutinins. We have readdressed this four decades old but still accepted recommendation with up to date methodology.Methods: Anti-A/B IgM- and IgG-antibodies were measured by Diamed-ID Micro Typing, surface plasmon resonance (SPR using the Biacore® device and flow cytometry.Results: When Diamed-ID Micro Typing was used, CVID patients (n=34 showed IgG- and IgM-isoagglutinins that were comparable to healthy volunteers (n=28, while all XLA patients (n=8 had none. Anti-A/B IgM-antibodies were present in more than 2/3 of the CVID patients and showed binding kinetics comparable to anti-A/B IgM-antibodies from healthy individuals. A correlation could be found in CVID patients between levels of anti-A/B IgM-antibodies and levels of serum IgM and PnP-IgM-antibodies. In contrast in CVID patients as a group ABO antibodies were significantly decreased when assessed by SPR, which correlated with levels of switched memory, non-switched memory and naïve B cells, but all CVID patients had low/undetectable anti-A/B IgG-antibodies.Conclusion: These results indicate that conventional isoagglutinin assessment and assessment of anti-A/B IgM antibodies are not suited for the diagnosis of impaired antibody production in CVID. Examination of anti-A/B IgG antibodies by SPR provides a useful method for the diagnosis of IgG antibody failure in all CVID patients studied, thus indicating an important additional rationale to start immunoglobulin replacement therapy early in these patients, before post-infectious sequelae develop.

  18. A Drosophila model of dominant inclusion body myopathy type 3 shows diminished myosin kinetics that reduce muscle power and yield myofibrillar defects.

    Suggs, Jennifer A; Melkani, Girish C; Glasheen, Bernadette M; Detor, Mia M; Melkani, Anju; Marsan, Nathan P; Swank, Douglas M; Bernstein, Sanford I

    2017-06-01

    Individuals with inclusion body myopathy type 3 (IBM3) display congenital joint contractures with early-onset muscle weakness that becomes more severe in adulthood. The disease arises from an autosomal dominant point mutation causing an E706K substitution in myosin heavy chain type IIa. We have previously expressed the corresponding myosin mutation (E701K) in homozygous Drosophila indirect flight muscles and recapitulated the myofibrillar degeneration and inclusion bodies observed in the human disease. We have also found that purified E701K myosin has dramatically reduced actin-sliding velocity and ATPase levels. Since IBM3 is a dominant condition, we now examine the disease state in heterozygote Drosophila in order to gain a mechanistic understanding of E701K pathogenicity. Myosin ATPase activities in heterozygotes suggest that approximately equimolar levels of myosin accumulate from each allele. In vitro actin sliding velocity rates for myosin isolated from the heterozygotes were lower than the control, but higher than for the pure mutant isoform. Although sarcomeric ultrastructure was nearly wild type in young adults, mechanical analysis of skinned indirect flight muscle fibers revealed a 59% decrease in maximum oscillatory power generation and an approximately 20% reduction in the frequency at which maximum power was produced. Rate constant analyses suggest a decrease in the rate of myosin attachment to actin, with myosin spending decreased time in the strongly bound state. These mechanical alterations result in a one-third decrease in wing beat frequency and marginal flight ability. With aging, muscle ultrastructure and function progressively declined. Aged myofibrils showed Z-line streaming, consistent with the human heterozygote phenotype. Based upon the mechanical studies, we hypothesize that the mutation decreases the probability of the power stroke occurring and/or alters the degree of movement of the myosin lever arm, resulting in decreased in vitro

  19. A Drosophila model of dominant inclusion body myopathy type 3 shows diminished myosin kinetics that reduce muscle power and yield myofibrillar defects

    Jennifer A. Suggs

    2017-06-01

    Full Text Available Individuals with inclusion body myopathy type 3 (IBM3 display congenital joint contractures with early-onset muscle weakness that becomes more severe in adulthood. The disease arises from an autosomal dominant point mutation causing an E706K substitution in myosin heavy chain type IIa. We have previously expressed the corresponding myosin mutation (E701K in homozygous Drosophila indirect flight muscles and recapitulated the myofibrillar degeneration and inclusion bodies observed in the human disease. We have also found that purified E701K myosin has dramatically reduced actin-sliding velocity and ATPase levels. Since IBM3 is a dominant condition, we now examine the disease state in heterozygote Drosophila in order to gain a mechanistic understanding of E701K pathogenicity. Myosin ATPase activities in heterozygotes suggest that approximately equimolar levels of myosin accumulate from each allele. In vitro actin sliding velocity rates for myosin isolated from the heterozygotes were lower than the control, but higher than for the pure mutant isoform. Although sarcomeric ultrastructure was nearly wild type in young adults, mechanical analysis of skinned indirect flight muscle fibers revealed a 59% decrease in maximum oscillatory power generation and an approximately 20% reduction in the frequency at which maximum power was produced. Rate constant analyses suggest a decrease in the rate of myosin attachment to actin, with myosin spending decreased time in the strongly bound state. These mechanical alterations result in a one-third decrease in wing beat frequency and marginal flight ability. With aging, muscle ultrastructure and function progressively declined. Aged myofibrils showed Z-line streaming, consistent with the human heterozygote phenotype. Based upon the mechanical studies, we hypothesize that the mutation decreases the probability of the power stroke occurring and/or alters the degree of movement of the myosin lever arm, resulting in

  20. A phase plane graph based model of the ovulatory cycle lacking the "positive feedback" phenomenon

    Kurbel Sven

    2012-08-01

    Full Text Available Abstract When hormones during the ovulatory cycle are shown in phase plane graphs, reported FSH and estrogen values form a specific pattern that resembles the leaning “&" symbol, while LH and progesterone (Pg values form a "boomerang" shape. Graphs in this paper were made using data reported by Stricker et al. [Clin Chem Lab Med 2006;44:883–887]. These patterns were used to construct a simplistic model of the ovulatory cycle without the conventional "positive feedback" phenomenon. The model is based on few well-established relations: hypothalamic GnRH secretion is increased under estrogen exposure during two weeks that start before the ovulatory surge and lasts till lutheolysis. the pituitary GnRH receptors are so prone to downregulation through ligand binding that this must be important for their function. in several estrogen target tissue progesterone receptor (PgR expression depends on previous estrogen binding to functional estrogen receptors (ER, while Pg binding to the expressed PgRs reduces both ER and PgR expression. Some key features of the presented model are here listed: High GnRH secretion induced by the recovered estrogen exposure starts in the late follicular phase and lasts till lutheolysis. The LH and FSH surges start due to combination of accumulated pituitary GnRH receptors and increased GnRH secretion. The surges quickly end due to partial downregulation of the pituitary GnRH receptors (64% reduction of the follicular phase pituitary GnRH receptors is needed to explain the reported LH drop after the surge. A strong increase in the lutheal Pg blood level, despite modest decline in LH levels, is explained as delayed expression of pituitary PgRs. Postponed pituitary PgRs expression enforces a negative feedback loop between Pg levels and LH secretions not before the mid lutheal phase. Lutheolysis is explained as a consequence of Pg binding to hypothalamic and pituitary PgRs that reduces local ER expression. When hypothalamic

  1. Effect of ovulatory follicle size and estradiol supplementation during the preovulatory period on pregnancy rates in postpartum beef cows

    In postpartum beef cows, GnRH-induced ovulation of small dominant follicles decreased pregnancy rates and increased late embryonic/fetal mortality; however, ovulatory follicle size had no apparent effect on the establishment or maintenance of pregnancy when ovulation occurred spontaneously. Further...

  2. Cows Milk-Dependent Exercise- Induced Anaphylaxis under the Condition of a Premenstrual or Ovulatory Phase Following Skin Sensitization

    Toshinori Bito

    2008-01-01

    Discussion: The symptoms against cows milk began when she took baths with bath salts containing cows milk as its main ingredient for one year at the age 15 years. Sensitization to cows milk through eczematous skin is indicated from this history. Hormonal change during a premenstrual or ovulatory phase is also an important factor for the development of FDEIA in this case.

  3. An homologous radioimmunoassay for chicken follicle-stimulating hormone: observations on the ovulatory cycle

    Scanes, C.G.; Godden, P.M.M.; Sharp, P.J.

    1977-01-01

    A highly purified FSH preparation has been used to develop a specific homologous radio-immunoassay for chicken FSH which is sufficiently sensitive and precise to measure the hormone in small samples (10-100 μl) of plasma. The assay was used to measure plasma FSH in the chicken and turkey. The FSH concentration was higher in sexually mature chickens than in juvenile birds and further elevated after castration or ovariectomy. In turkeys, it was lower in birds held on a short daily photoperiod than in birds held on a long daily photoperiod. FSH rose in sexually quiescent female turkeys after injection of synthetic L-H releasing hormone and was increased in laying hens after injection of progesterone. No major changes were observed in FSH concentration during the chicken ovulatory cycle, although there was a small increase between 15 and 14 h before ovulation. (author)

  4. Lean muscle mass in classic or ovulatory PCOS: association with central obesity and insulin resistance.

    Mario, F M; do Amarante, F; Toscani, M K; Spritzer, P M

    2012-10-01

    This age-matched case-control study assessed total and segmental lean muscle mass in classic or ovulatory polycystic ovary syndrome (PCOS) patients and investigated whether lean mass is associated with hormone and metabolic features. Participants underwent anthropometric and clinical evaluation. Habitual physical activity was assessed with a digital pedometer, and body composition by dual-energy X-ray absorptiometry. Laboratory measurements included total cholesterol, cholesterol fractions, triglycerides, glucose, total serum testosterone, serum insulin, estradiol, luteinizing hormone, and SHBG. Energy intake was calculated using a food frequency questionnaire. Classic PCOS patients had higher body mass index (BMI), waist circumference, testosterone and lipid accumulation product values than ovulatory PCOS and controls. Energy consumption, homeostasis model assessment index, SHBG, free androgen index and triglycerides, total and trunk lean mass were higher only in classic PCOS women vs. controls. Arm, leg, trunk, total or limb lean masses were not correlated with hormone levels in any of the groups. However, in PCOS women lipid accumulation product was positively correlated with total (r=0.56, p=0.001), trunk (r=0.59, p=0.001), arm (r=0.54, p=0.001), leg (r=0.44, p=0.03) and limb (r=0.48, p=0.001) lean masses. BMI was positively correlated with all lean mass segments and independently associated with total lean mass. Lipid accumulation product and BMI were independently associated with trunk lean mass variation. The increase in lean mass in classic PCOS appears to be associated with insulin resistance and central obesity rather than with energy intake, physical activity or androgens. © J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart · New York.

  5. New radioimmunoassay for follicle-stimulating hormone in macaques: ovulatory menstrual cycles. [/sup 125/I tracer technique

    Hodgen, G.D.; Wilks, J.W.; Vaitukaitis, J.L.; Chen, H.C.; Papkoff, H.; Ross, G.

    1976-07-01

    A sensitive and specific radioimmunoassay system for macaque follicle-stimulating hormone (mFSH) was developed utilizing an antiserum (H-31) prepared in a rabbit against purified ovine FSH as the immunogen. Sera from castrated female, adult male, and juvenile rhesus monkeys, as well as urinary extracts from castrated rhesus and bonnet monkeys, were used to demonstrate parallelism with a standard of partially purified monkey pituitary gonadotropins (LER-M-907-D). An extract of baboon pituitary tissue also showed parallelism with the reference standard. A highly purified pituitary extract (WP-X-105-28), containing approximately 75 percent macaque luteinizing hormone (mLH) and 1 percent mFSH, was used to demonstrate the specificity of this mFSH assay system. Sera and urinary extracts obtained from hypophysectomized monkeys did not show cross-reactivity in the assay. Macaque chorionic gonadotropin (mCG) did not produce an inhibition curve in the assay, as determined from serum samples and urinary extracts collected from pregnant monkeys at the time of peak mCG secretion. Serum concentrations of mFSH were suppressed in ovariectomized monkeys by the administration of ethinyl estradiol for 3 days, but returned to near pretreatment values by 96 h after the last estradiol administration. The determination of serum mFSH concentrations in daily blood samples obtained from 20 rhesus monkeys throughout ovulatory menstrual cycles revealed a pattern similar to that previously reported for the rhesus monkey and the woman. The peak value of serum mFSH during the menstrual cycle coincided with the midcycle surge of mLH in each case. The gonadotropin peaks were preceded by increasing serum concentrations of estradiol and followed by rises in the serum concentrations of progesterone.

  6. Radioimmunoassay method for measurement of plasma androstenedione. Its validation in ovulatory women and in patients with polycystic ovarian syndrome; Metodo de radioimunoensaio para medida da androstenediona plasmatica. Validacao em mulheres ovulatorias e com sindrome dos ovarios policisticos

    Vilanova Socorro Veras, Maria do; Silva e Rosa, Alzira Amelia; Moura, Marcos Dias de; Ferriano, Rui Alberto; Sa, Marcos Felipe Silva de [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Medicina

    1995-01-01

    The present paper has as objective the standardization of a radioimmunoassay method for measurement of androstenedione. Ethyl ether was used for plasma extraction. The sensitivity of the method was 6,8 pg/tube; the reproducibility (inter assay error) was 15,6%; the precision (intrassay error) was 5,2%. As biological control, 20 ovulatory women showed median plasma values of 1250 pg/ml and 24 women with polycystic ovary syndrome presented median plasma values of 2.037 pg/ml. (author). 6 refs., 2 figs., 1 tab.

  7. Effects of leptin administration on development, vascularization and function of Corpus luteum in alpacas submitted to pre-ovulatory fasting.

    Norambuena, María Cecilia; Hernández, Francisca; Maureira, Jonathan; Rubilar, Carolina; Alfaro, Jorge; Silva, Gonzalo; Silva, Mauricio; Ulloa-Leal, César

    2017-07-01

    The objective of this study was to determine the effect of leptin administration on the development, vascularization and function of Corpus luteum (CL) in alpacas submitted to pre-ovulatory fasting. Fourteen alpacas were kept in fasting conditions for 72h and received five doses of o-leptin (2μg/kg e.v.; Leptin group) or saline (Control group) every 12h. Ovulation was induced with a GnRH dose (Day 0). The ovaries were examined every other day by trans-rectal ultrasonography (7.5MHz; mode B and power Doppler) from Day 0 to 13 to determine the pre-ovulatory follicle diameter and ovulation, and then to monitor CL diameter and vascularization until the regression phase. Serial blood samples were taken after GnRH treatment to determine plasma LH concentration; and every other day from Days 1 to 13 to determine plasma progesterone and leptin concentrations. The pre-ovulatory follicle and CL diameter, LH, progesterone and leptin plasma concentrations were not affected by treatment (P>0.05). The vascularization area of the CL was, nevertheless, affected by the treatment (P<0.01) with significant differences between groups at Days 3, 7 and 9 (P<0.05). The Leptin group had a larger maximum vascularization area (0.67±0.1 compared with 0.35±0.1cm 2 ; P<0.05). In addition, there was a positive correlation between CL vascularization, CL diameter and plasma progesterone. The exogenous administration of leptin during pre-ovulatory fasting increased the vascularization of the CL in alpacas in vivo. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. The effect of repeated administrations of llama ovulation-inducing factor (OIF/NGF) during the peri-ovulatory period on corpus luteum development and function in llamas.

    Fernández, A; Ulloa-Leal, C; Silva, M; Norambuena, C; Adams, G P; Guerra, M; Ratto, M H

    2014-10-01

    The objective of the study was to test the hypothesis that repeated administrations of OIF/NGF during the peri-ovulatory period (pre-ovulatory, ovulatory, early post-ovulatory), will enhance the luteotrophic effect in llamas. Female llamas were examined daily by transrectal ultrasonography in B- and Doppler-mode using a scanner equipped with a 7.5-MHz linear-array transducer to monitor ovarian follicle and luteal dynamics. When a growing follicle ≥7mm was detected, llamas were assigned randomly to one of the three groups and given 1mg of purified OIF/NGF im (intramuscular) (a) pre-ovulation (single dose; n=12), (b) pre-ovulation and at the time of ovulation (2 doses, n=10), or (c) pre-ovulation, at the time of ovulation, and 24h after ovulation (3 doses, n=10). The pre-ovulatory follicle diameter at the time of treatment, ovulation rate and the first day of CL detection did not differ (P=0.3) among groups. However, maximum CL diameter was greatest (P=0.003) in llamas in the 2-dose group, and smallest in the 3-dose group. Accordingly, the 2 dose-group had the largest day-to-day profile for CL diameter (Pllama seminal plasma is luteotrophic and the effect on CL size and function is affected by the number and timing of treatments during the peri-ovulatory period. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Size of ovulatory follicles in cattle expressing multiple ovulations naturally and its influence on corpus luteum development and fertility.

    Echternkamp, S E; Cushman, R A; Allan, M F

    2009-11-01

    Long-term genetic selection of cattle for fraternal twins has increased the frequency of twin and triplet ovulations. In contrast, the ratio of fetal numbers to ovulation sites in pregnant females with twin (0.83) or triplet (0.73) ovulations is conception in cyclic cattle expressing multiple ovulations naturally, including the effect of ovulation rate on follicle or corpus luteum (CL) size, and their relationship to conception. Diameter of the individual ovulatory follicles was measured by transrectal ultrasonography at AI and ranged from 8 to 30 mm, with a trend for diameter of the individual follicles, and associated CL, to decrease with increasing ovulation rate. Independent of ovulation rate, ovulatory follicles were smaller (P or =2.5 yr). Pregnancy and fetal status were diagnosed by transrectal ultrasonography between 42 and 72 d after AI. Fertility was reduced (P or =22 vs. 14 to 17.9 mm). Plasma progesterone concentrations increased with ovulation rate and were correlated positively with total CL or ovulatory follicle volume per female, indicating that CL size and function were influenced by the size of the follicle of origin. Progesterone was greater (P uterine crowding, especially when 2 or more fetuses were contained within 1 uterine horn.

  10. Birth Defects

    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 ...

  11. Embedded defects

    Barriola, M.; Vachaspati, T.; Bucher, M.

    1994-01-01

    We give a prescription for embedding classical solutions and, in particular, topological defects in field theories which are invariant under symmetry groups that are not necessarily simple. After providing examples of embedded defects in field theories based on simple groups, we consider the electroweak model and show that it contains the Z string and a one-parameter family of strings called the W(α) string. It is argued that although the members of this family are gauge equivalent when considered in isolation, each member becomes physically distinct when multistring configurations are considered. We then turn to the issue of stability of embedded defects and demonstrate the instability of a large class of such solutions in the absence of bound states or condensates. The Z string is shown to be unstable for all values of the Higgs boson mass when θ W =π/4. W strings are also shown to be unstable for a large range of parameters. Embedded monopoles suffer from the Brandt-Neri-Coleman instability. Finally, we connect the electroweak string solutions to the sphaleron

  12. Synthetic Defects for Vibrothermography

    Renshaw, Jeremy; Holland, Stephen D.; Thompson, R. Bruce; Eisenmann, David J.

    2010-02-01

    Synthetic defects are an important tool used for characterizing the performance of nondestructive evaluation techniques. Viscous material-filled synthetic defects were developed for use in vibrothermography (also known as sonic IR) as a tool to improve inspection accuracy and reliability. This paper describes how the heat-generation response of these VMF synthetic defects is similar to the response of real defects. It also shows how VMF defects can be applied to improve inspection accuracy for complex industrial parts and presents a study of their application in an aircraft engine stator vane.

  13. Family of defect-dicubane Ni4Ln2 (Ln = Gd, Tb, Dy, Ho) and Ni4Y2 complexes: rare Tb(III) and Ho(III) examples showing SMM behavior.

    Zhao, Lang; Wu, Jianfeng; Ke, Hongshan; Tang, Jinkui

    2014-04-07

    Reactions of Ln(III) perchlorate (Ln = Gd, Tb, Dy, and Ho), NiCl2·6H2O, and a polydentate Schiff base resulted in the assembly of novel isostructural hexanuclear Ni4Ln2 complexes [Ln = Gd (1), Tb (2), Dy (3), Ho (4)] with an unprecedented 3d-4f metal topology consisting of two defect-dicubane units. The corresponding Ni4Y2 (5) complex containing diamagnetic Y(III) atoms was also isolated to assist the magnetic studies. Interestingly, complexes 2 and 3 exhibit SMM characteristics and 4 shows slow relaxation of the magnetization. The absence of frequency-dependent in-phase and out-of-phase signals for the Ni-Y species suggests that the Ln ions' contribution to the slow relaxation must be effectual as previously observed in other Ni-Dy samples. However, the observation of χ″ signals with zero dc field for the Ni-Tb and Ni-Ho derivatives is notable. Indeed, this is the first time that such a behavior is observed in the Ni-Tb and Ni-Ho complexes.

  14. Intake of vinegar beverage is associated with restoration of ovulatory function in women with polycystic ovary syndrome.

    Wu, Di; Kimura, Fuminori; Takashima, Akiko; Shimizu, Yoshihiko; Takebayashi, Akie; Kita, Nobuyuki; Zhang, Guangmei; Murakami, Takashi

    2013-05-01

    Polycystic ovary syndrome (PCOS) is one of major causes of irregular menstruation. It is defined as a condition involving the combination of hyperandrogenism and chronic oligomenorrhea or anovulation, and is thought to have a variety of etiologies. Insulin resistance (impaired insulin sensitivity) has been suggested to be one of the etiologies of PCOS. PCOS patients often need to take medication to treat anovulation and infertility. Therefore, it would be beneficial to patients if simple non-pharmacological treatments can be developed. Recently the efficacy of vinegar to improve insulin resistance has been reported. To study the effect of vinegar on metabolic and hormonal indices and ovulatory function in PCOS, seven patients seeking a non-pharmacological treatment for PCOS took a beverage containing 15 g of apple vinegar daily for 90 to 110 days. Ovulation, the menstrual interval, fasting serum glucose level, fasting serum insulin level, luteinizing hormone (LH), follicle stimulating hormone (FSH), and testosterone were compared before and after intake of the vinegar beverage. Intake of the vinegar beverage resulted in a decrease of the homeostasis model assessment insulin resistance index (HOMA-R) in six patients, as well as a decrease of the LH/FSH ratio in five of seven patients. Ovulatory menstruation was observed within 40 day in four of seven patients. These findings suggest the possibility of vinegar to restore ovulatory function through improving insulin sensitivity in PCOS patients, thus, avoiding pharmacological treatment. Intake of vinegar might reduce medical cost and treatment time for insulin resistance, anovulation, and infertility in patients with PCOS.

  15. Sources of variation and genetic profile of spontaneous, out-of-season ovulatory activity in the Chios sheep

    Kouttos Athanasios

    2003-01-01

    Full Text Available Abstract Organising the breeding plan of a seasonally breeding species, such as sheep, presents a challenge to farmers and the industry as a whole, since both economical and biological considerations need to be carefully balanced. Understanding the breeding activity of individual animals becomes a prerequisite for a successful breeding program. This study set out to investigate the sources of variation and the genetic profile of the spontaneous, out-of-season ovulatory activity of ewes of the Chios dairy sheep breed in Greece. The definition of the trait was based on blood progesterone levels, measured before exposing the ewes to rams, which marks the onset of the usual breeding season. Data were 707 records, taken over two consecutive years, of 435 ewes kept at the Agricultural Research Station of Chalkidiki in northern Greece. When all available pedigree was included, the total number of animals involved was 1068. On average, 29% of all ewes exhibited spontaneous, out-of-season ovulatory activity, with no substantial variation between the years. Significant sources of systematic variation were the ewe age and live weight, and the month of previous lambing. Older, heavier ewes, that had lambed early the previous autumn, exhibited more frequent activity. Heritability estimates were 0.216 (± 0.084 with a linear and 0.291 with a threshold model. The latter better accounts for the categorical nature of the trait. The linear model repeatability was 0.230 (± 0.095. The results obtained in this study support the notion that spontaneous out-of-season ovulatory activity can be considered in the development of a breeding plan for the Chios sheep breed.

  16. The Woman in Red: Examining the Effect of Ovulatory Cycle on Women's Perceptions of and Behaviors Toward Other Women.

    Netchaeva, Ekaterina; Kouchaki, Maryam

    2018-04-01

    Previous research has shown that during her monthly peak fertile window, a woman competes with other women for a suitable mate. Drawing upon research on ovulation and socially constructed meanings of the color red, we examine how a woman's fertility status and red clothing worn by a target woman change perceptions of the target, as well as behaviors toward the target. Following previous research on the ovulatory status and color red effects, we rely on both hormonal and self-reported fertility data. Across six studies, our research fails to provide support for the prediction that an ovulating woman is less likely to trust another woman wearing red compared with a nonovulating woman.

  17. Defect modelling

    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)

  18. Omega-3 polyunsaturated fatty acid docosahexaenoic acid and its role in exhaustive-exercise-induced changes in female rat ovulatory cycle.

    Mostafa, Abeer F; Samir, Shereen M; Nagib, R M

    2018-04-01

    Exhaustive exercises can cause delayed menarche or menstrual cycle irregularities in females. Omega-3 polyunsaturated fatty acids (ω-3 PUFAs) are incorporated into a wide range of benefits in many physiological systems. Our work aimed to assess the role of ω-3 PUFA docosahexaenoic acid (DHA) on the deleterious effects of exhaustive exercise on the female reproductive system in rats. Virgin female rats were randomly divided into 4 groups (12 rats in each): control group, omega-3 group treated with DHA, exhaustive exercise group, and exhaustive exercised rats treated with DHA. Omega-3 was given orally to the rats once daily for 4 estrous cycles. Exhaustive exercises revealed lower levels in progesterone and gonadotropins together with histopathological decrease in number of growing follicles and corpora lutea. Moreover, the exercised rats showed low levels of ovarian antioxidants with high level of caspase-3 and plasma cortisol level that lead to disruption of hypothalamic-pituitary-gonadal axis. ω-3 PUFA DHA has beneficial effects on the number of newly growing follicles in both sedentary and exercised rats with decreasing the level of caspase-3 and increasing the antioxidant activity in ovaries. Exhaustive exercises can cause ovulatory problems in female rats that can be improved by ω-3 supplementation.

  19. SEASONAL VARIATION IN OVULATORY ACTIVITY OF NUBIAN, ALPINE AND NUBIAN X CREOLE DOES UNDER TROPICAL PHOTOPERIOD (22° N

    Jorge Urrutia Morales

    2011-09-01

    Full Text Available In the present study, seasonal variation in ovulatory activity of Nubian, Alpine and Criollox Nubian goats in the semiarid region of central-northern Mexico (22° 14’ N was examined. The study was conducted under natural photoperiod and climate conditions during a whole year. Eight female goats per breed were grouped separately and exposed to visual, olfactory and audible signals of bucks. Blood samples were obtained twice per week and serum progesterone concentrations were determined. All goats presented a clear pattern of seasonal ovulatory activity based on serum progesterone profiles. Length of the ovulatory activity period did not differ between genotypes (P >0.10, and had an average duration of 4.3 months. Nevertheless Criollo x Nubian goats presented greater individual variation in dates of onset and end as well as length of this period (P <0.05. Results indicate that female goats of genotypes which differ in latitude of origin, express a similar restricted pattern of seasonal ovulatory activity when subjected to small annual changes in phtoperiod, adequate nutrition and incomplete socio-sexual stimulus.

  20. MicroRNA expression profiles from eggs of different qualities associated with post-ovulatory ageing in rainbow trout (Oncorhynchus mykiss)

    Background: Egg quality is an important aspect in rainbow trout farming. Post-ovulatory aging is one of the most important factors affecting egg quality. MicroRNAs (miRNAs) are the major regulators in various biological processes and their expression profiles could serve as reliable biomarkers for v...

  1. Changes in sleep time and sleep quality across the ovulatory cycle as a function of fertility and partner attractiveness.

    Brooke N Gentle

    Full Text Available Research suggests that near ovulation women tend to consume fewer calories and engage in more physical activity; they are judged to be more attractive, express greater preferences for masculine and symmetrical men, and experience increases in sexual desire for men other than their primary partners. Some of these cycle phase shifts are moderated by partner attractiveness and interpreted as strategic responses to women's current reproductive context. The present study investigated changes in sleep across the ovulatory cycle, based on the hypothesis that changes in sleep may reflect ancestral strategic shifts of time and energy toward reproductive activities. Participants completed a 32-day daily diary in which they recorded their sleep time and quality for each day, yielding over 1,000 observations of sleep time and quality. Results indicated that, when the probability of conception was high, women partnered with less attractive men slept more, while women with more attractive partners slept less.

  2. Defects and defect processes in nonmetallic solids

    Hayes, W

    2004-01-01

    This extensive survey covers defects in nonmetals, emphasizing point defects and point-defect processes. It encompasses electronic, vibrational, and optical properties of defective solids, plus dislocations and grain boundaries. 1985 edition.

  3. Non-reproductive Effects of Anovulation: Bone Metabolism in the Luteal Phase of Premenopausal Women Differs between Ovulatory and Anovulatory Cycles.

    Niethammer, B; Körner, C; Schmidmayr, M; Luppa, P B; Seifert-Klauss, V R

    2015-12-01

    Introduction: Several authors have linked subclinical ovulatory disturbances in normal length menstrual cycles to premenopausal fracture risk and bone changes. This study systematically examined the influence of ovulation and anovulation on the bone metabolism of premenopausal women. Participants and Methods: In 176 cycles in healthy premenopausal women, FSH, 17β-estradiol (E2) and progesterone (P4) as well as bone alkalic phosphatase (BAP), pyridinoline (PYD) and C-terminal crosslinks (CTX) were measured during the follicular and during the luteal phase. The probability and timing of ovulation was self-assessed by a monitoring device. In addition, bone density of the lumbar spine was measured by quantitative computed tomography (QCT) at baseline and at the end of the study. Analysis was restricted to blood samples taken more than three days before the following menstruation. Results: 118 cycles out of the 176 collected cycles were complete with blood samples taken within the correct time interval. Of these, 56.8 % were ovulatory by two criteria (ovulation symbol shown on the monitor display and LP progesterone > 6 ng/ml), 33.1 % were possibly ovulatory by one criterion (ovulation symbol shown on the monitor display or LP progesterone > 6 ng/ml), and 10.2 % were anovulatory by both criteria). Ovulation in the previous cycle and in the same cycle did not significantly influence the mean absolute concentrations of the bone markers. However, bone formation (BAP) was higher in the luteal phase of ovulatory cycles than in anovulatory cycles (n. s.) and the relative changes within one cycle were significantly different for bone resorption (CTX) during ovulatory vs. anovulatory cycles (p cycles following each other directly, both ovulation in the previous cycle and ovulation in the present cycle influenced CTX, but not the differences of other bone markers. Conclusion: Ovulatory cycles reduce bone resorption in their luteal phase and that of the

  4. Birth after human chorionic gonadotropin-primed oocyte in vitro maturation and fertilization with testicular sperm in a normo-ovulatory patient

    Claudia González-Ortega

    2016-01-01

    Full Text Available In this report, we present a case of in vitro maturation (IVM with surgical retrieved testicular sperm in a normo-ovulatory female. Human chorionic gonadotropin-primed IVM, testicular biopsy for sperm retrieval and intracytoplasmic sperm injection with fresh sperm were performed. Fourteen cumulus-oocyte complexes were obtained in germinal vesicle or metaphase I stage, eight oocytes reached metaphase II, seven presumptive zygotes were obtained, and three cleavage stages embryos in day 2 were transferred producing a singleton pregnancy. A single healthy newborn was obtained. Our results suggest that IVM may be an alternative for in vitro fertilization in normo-ovulatory women even if surgical retrieval of sperm is needed. Further research is required to depict contributing factors to the success of IVM in indications different from polycystic ovaries syndrome and the role of male gamete.

  5. Human chorionic gonadotropin-administered natural cycle versus spontaneous ovulatory cycle in patients undergoing two pronuclear zygote frozen-thawed embryo transfer.

    Lee, You-Jung; Kim, Chung-Hoon; Kim, Do-Young; Ahn, Jun-Woo; Kim, Sung-Hoon; Chae, Hee-Dong; Kang, Byung-Moon

    2018-03-01

    To compare human chorionic gonadotropin (HCG)-administered natural cycle with spontaneous ovulatory cycle in patients undergoing frozen-thawed embryo transfer (FTET) in natural cycles. In this retrospective cohort study, we analyzed the clinical outcome of a total of 166 consecutive FTET cycles that were performed in either natural cycle controlled by HCG for ovulation triggering (HCG group, n=110) or natural cycle with spontaneous ovulation (control group, n=56) in 166 infertile patients between January 2009 and November 2013. There were no differences in patients' characteristics between the 2 groups. The numbers of oocytes retrieved, mature oocytes, fertilized oocytes, grade I or II embryos and frozen embryos in the previous in vitro fertilization (IVF) cycle in which embryos were frozen were comparable between the HCG and control groups. Significant differences were not also observed between the 2 groups in clinical pregnancy rate (CPR), embryo implantation rate, miscarriage rate, live birth rate and multiple CPR. However, the number of hospital visits for follicular monitoring was significantly fewer in the HCG group than in the control group ( P cycle reduces the number of hospital visits for follicular monitoring without any detrimental effect on FTET outcome when compared with spontaneous ovulatory cycles in infertile patients undergoing FTET in natural ovulatory cycles.

  6. Intra-uterine insemination: pregnancy rate in relation to number, size of pre-ovulatory follicles and day of insemination.

    Karuppaswamy, J; Smedley, Mamin; Carter, Lindsay

    2009-03-01

    The objective of the study was to analyse the pregnancy rate in intra-uterine insemination (IUI) in relation to pre-ovulatory follicular number, size and day of insemination. A retrospective analysis of 216 completed IUI cycles was used in an attempt to identify significant variables predictive of treatment success. Couples with unexplained infertility and male factor infertility underwent IUI with or without ovarian stimulation. The mean number of IUI cycles per patient was 4.1, the overall pregnancy rate was 27.3% per patient, and the pregnancy rate per cycle was 6.9%. The pregnancy rate was 4.4% when one follicle was produced, whereas with more than two follicles, the rate increased to 21.2%. Hormonal stimulation using clomiphene citrate and/or human menopausal gonadotrophin/follicle stimulating hormone yielded a significant higher pregnancy rate compared to IUI in natural cycles (10.3% versus 3.3%). Although not statistically significant, the pregnancy rate decreased with advancing age of woman. The results suggest that IUI is a useful method of assisted conception in unexplained infertility and higher pregnancy rates can be achieved with good patient selection and ovarian stimulation.

  7. Muscles in a mouse model of spinal muscular atrophy show profound defects in neuromuscular development even in the absence of failure in neuromuscular transmission or loss of motor neurons

    Lee, Young il; Mikesh, Michelle; Smith, Ian; Rimer, Mendell; Thompson, Wesley

    2011-01-01

    A mouse model of the devastating human disease "spinal muscular atrophy" (SMA) was used to investigate the severe muscle weakness and spasticity that precedes the death of these animals near the end of the 2nd postnatal week. Counts of motor units to the soleus muscle as well as of axons in the soleus muscle nerve showed no loss of motor neurons. Similarly, neither immunostaining of neuromuscular junctions nor the measurement of the tension generated by nerve stimulation gave evidence of any ...

  8. Plasma lipid peroxidation, blood GSH concentration and erythrocyte antioxidant enzymes in menstruating females with ovulatory and anovulatory cycles compared with males

    G Lutosławska

    2003-12-01

    Full Text Available This study was undertaken to evaluate plasma TBARS and blood GSH concentration and erythrocyte antioxidant enzymes (glutathione peroxidase, catalase and superoxide dismutase in active, regularly menstruating female physical education students with ovulatory and anovulatory menstrual cycles and in their male counterparts. A total of 27 subjects (12 males and 15 females volunteered to participate in the study. All females were regularly menstruating with cycle length between 26-31 days. Plasma progesterone and 17-β-estradiol concentrations were assayed during the 7th-9th and 22nd-25th day of the menstrual cycle. Women with plasma progesterone concentration exceeding 19 nmol•l-1 during the 22nd-25th day were referred to as ovulatory (Group OV; n=7. Women without a peak plasma progesterone concentration were referred to as anovulatory (Group AN; n=8. Blood from male subjects was withdrawn twice - two weeks apart, at their convenience. It was found that the menstrual cycle phases did not affect plasma TBARS and blood glutathione concentration and erythrocyte GPX, CAT and SOD activity. However, erythrocyte GPX activity either in ovulatory or anovulatory women was by about 30% higher than in male subjects. Erythrocyte SOD activity in ovulatory women both in follicular and luteal phase of the menstrual cycle (1557 U/g Hb and 1394.6 U/g Hb, respectively was markedly lower than in men (1951.8 and 1937.7 U/g Hb for blood sampling I and II, respectively. In contrast, erythrocyte SOD activity in anovulatory women (1855.5 U/g Hb and 1745.7 U/g Hb in the follicular and luteal phases, respectively was similar to that found in men. The above data indicated that erythrocyte GPX and SOD activities are sensitive to plasma ovarian hormone concentration. In addition, they suggested that due to higher erythrocyte GPX activity females even with anovulatory menstrual cycles are protected better than males against hydrogen peroxide action. However, lower superoxide

  9. Muscles in a mouse model of spinal muscular atrophy show profound defects in neuromuscular development even in the absence of failure in neuromuscular transmission or loss of motor neurons.

    Lee, Young Il; Mikesh, Michelle; Smith, Ian; Rimer, Mendell; Thompson, Wesley

    2011-08-15

    A mouse model of the devastating human disease "spinal muscular atrophy" (SMA) was used to investigate the severe muscle weakness and spasticity that precede the death of these animals near the end of the 2nd postnatal week. Counts of motor units to the soleus muscle as well as of axons in the soleus muscle nerve showed no loss of motor neurons. Similarly, neither immunostaining of neuromuscular junctions nor the measurement of the tension generated by nerve stimulation gave evidence of any significant impairment in neuromuscular transmission, even when animals were maintained up to 5days longer via a supplementary diet. However, the muscles were clearly weaker, generating less than half their normal tension. Weakness in 3 muscles examined in the study appears due to a severe but uniform reduction in muscle fiber size. The size reduction results from a failure of muscle fibers to grow during early postnatal development and, in soleus, to a reduction in number of fibers generated. Neuromuscular development is severely delayed in these mutant animals: expression of myosin heavy chain isoforms, the elimination of polyneuronal innervation, the maturation in the shape of the AChR plaque, the arrival of SCs at the junctions and their coverage of the nerve terminal, the development of junctional folds. Thus, if SMA in this particular mouse is a disease of motor neurons, it can act in a manner that does not result in their death or disconnection from their targets but nonetheless alters many aspects of neuromuscular development. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Effects of supervised aerobic training on the levels of anti-Mullerian hormone and adiposity measures in women with normo-ovulatory and polycystic ovary syndrome.

    Al-Eisa, Einas; Gabr, Sami Ali; Alghadir, Ahmad Hieder

    2017-04-01

    To evaluate the change in the levels of anti-Mullerian hormone, adiponectin, weight loss and fertility parameters in obese women with or without polycystic ovary syndrome, following 12 weeks of supervised aerobic exercise. This study was conducted from August 2013 to October 2014 among obese women with or without polycystic ovary syndrome referred to Obstetrics and Gynecology clinic, Mansoura University Hospital, Faculty of Medicine, Mansoura, Egypt. Patients were classified into three age-matched groups; group A had controls, group B had patients with polycystic ovary syndrome and group C had obese women. Anti-Mullerian hormone, adiponectin, follicle-stimulating hormone, oestrogen, fasting insulin, fasting glucose, homeostasis model of assessment of insulin resistance, antral follicle count, hirsutism score, weight, menstrual cyclicity and ovulatory function were assessed at baseline and following 12 weeks of supervised aerobic exercise. Statistical analysis was performed using SPSS 17. Of the 90 patients, there were 30(33.3%) in each group. The mean age was 28.7±3.84 years in group A, 27.9±4.1 years in group B and 27.6±5.7 in group C. The 30(33.3%) participants who responded to aerobic exercise interventions showed significant improvements in reproductive function), with lower baseline anti-Mullerian hormone levels, greater weight loss and higher adiponectin level compared to the the 30(33.3%) participants who did not respond to the exercise programme. Weight loss, fertility hormones, follicle-stimulating hormone, prolactin, oestrogen, antral follicle count, baseline anti-Mullerian hormone, and adiponectin were significantly correlated to the improvement in reproductive function (psyndromes, there were significant improvements in ovarian process with an ovulation rate of 13(43.3%) and a restoration of menstrual cycle with a rate of 17(56.7 %) following 12 weeks of supervised aerobic exercise. Moderate aerobic training for 12 weeks had a positive significant

  11. Defect detection using transient thermography

    Mohd Zaki Umar; Ibrahim Ahmad; Ab Razak Hamzah; Wan Saffiey Wan Abdullah

    2008-08-01

    An experimental research had been carried out to study the potential of transient thermography in detecting sub-surface defect of non-metal material. In this research, eight pieces of bakelite material were used as samples. Each samples had a sub-surface defect in the circular shape with different diameters and depths. Experiment was conducted using one-sided Pulsed Thermal technique. Heating of samples were done using 30 kWatt adjustable quartz lamp while infra red (IR) images of samples were recorded using THV 550 IR camera. These IR images were then analysed with ThermofitTMPro software to obtain the Maximum Absolute Differential Temperature Signal value, ΔΤ m ax and the time of its appearance, τ m ax (ΔΤ). Result showed that all defects were able to be detected even for the smallest and deepest defect (diameter = 5 mm and depth = 4 mm). However the highest value of Differential Temperature Signal (ΔΤ m ax), were obtained at defect with the largest diameter, 20 mm and at the shallowest depth, 1 mm. As a conclusion, the sensitivity of the pulsed thermography technique to detect sub-surface defects of bakelite material is proportionately related with the size of defect diameter if the defects are at the same depth. On the contrary, the sensitivity of the pulsed thermography technique inversely related with the depth of defect if the defects have similar diameter size. (Author)

  12. Defect detection module

    Ernwein, R.; Westermann, G.

    1986-01-01

    The ''defect detector'' module is aimed at exceptional event or state recording. Foreseen for voltage presence monitoring on high supply voltage module of drift chambers, its characteristics can also show up the vanishing of supply voltage and take in account transitory fast signals [fr

  13. Norwegian Pitched Roof Defects

    Lars Gullbrekken

    2016-06-01

    Full Text Available The building constructions investigated in this work are pitched wooden roofs with exterior vertical drainpipes and wooden load-bearing system. The aim of this research is to further investigate the building defects of pitched wooden roofs and obtain an overview of typical roof defects. The work involves an analysis of the building defect archive from the research institute SINTEF Building and Infrastructure. The findings from the SINTEF archive show that moisture is a dominant exposure factor, especially in roof constructions. In pitched wooden roofs, more than half of the defects are caused by deficiencies in design, materials, or workmanship, where these deficiencies allow moisture from precipitation or indoor moisture into the structure. Hence, it is important to increase the focus on robust and durable solutions to avoid defects both from exterior and interior moisture sources in pitched wooden roofs. Proper design of interior ventilation and vapour retarders seem to be the main ways to control entry from interior moisture sources into attic and roof spaces.

  14. Photographic guide of selected external defect indicators and associated internal defects in sugar maple

    Everette D. Rast; John A. Beaton; David L. Sonderman

    1991-01-01

    To properly classify or grade logs or trees, one must be able to correctly identify defect indicators and assess the effect of the underlying defect on possible end products. This guide assists the individual in identifying the surface defect indicator and shows the progressive stages of the defect throughout its development for sugar maple. Eleven types of external...

  15. Photographic guide of selected external defect indicators and associated internal defects in yellow-poplar

    Everette D. Rast; John A. Beaton; David L. Sonderman

    1991-01-01

    To properly classify or grade logs or trees, one must be able to correctly identify defect indicators and assess the effect of the underlying defect on possible end products. This guide assists the individual in identifying the surface defect indicator and shows the progressive stages of the defect throughout its development for yellow-poplar. Twelve types of external...

  16. Photographic guide of selected external defect indicators and associated internal defects in yellow birch

    Everette D. Rast; John A. Beaton; David L. Sonderman

    1991-01-01

    To properly classify or grade logs or trees, one must be able to correctly identify defect indicators and assess the effect of the underlying defect on possible end products. This guide assists the individual in identifying the surface defect indicator and shows the progressive stages of the defect throughout its development for yellow birch. Eleven types of external...

  17. Women's preferences for men's beards show no relation to their ovarian cycle phase and sex hormone levels.

    Dixson, Barnaby J W; Lee, Anthony J; Blake, Khandis R; Jasienska, Grazyna; Marcinkowska, Urszula M

    2018-01-01

    According to the ovulatory shift hypothesis, women's mate preferences for male morphology indicative of competitive ability, social dominance, and/or underlying health are strongest at the peri-ovulatory phase of the menstrual cycle. However, recent meta-analyses are divided on the robustness of such effects and the validity of the often-used indirect estimates of fertility and ovulation has been called into question in methodological studies. In the current study, we test whether women's preferences for men's beardedness, a cue of male sexual maturity, androgenic development and social dominance, are stronger at the peri-ovulatory phase of the menstrual cycle compared to during the early follicular or the luteal phase. We also tested whether levels of estradiol, progesterone, and the estradiol to progesterone ratio at each phase were associated with facial hair preferences. Fifty-two heterosexual women completed a two-alternative forced choice preference test for clean-shaven and bearded male faces during the follicular, peri-ovulatory (validated by the surge in luteinizing hormone or the drop in estradiol levels) and luteal phases. Participants also provided for one entire menstrual cycle daily saliva samples for subsequent assaying of estradiol and progesterone. Results showed an overall preference for bearded over clean-shaven faces at each phase of the menstrual cycle. However, preferences for facial hair were not significantly different over the phases of menstrual cycle and were not significantly associated with levels of reproductive hormones. We conclude that women's preferences for men's beardedness may not be related to changes in their likelihood of conception. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. The majority of irregular menstrual cycles in adolescence are ovulatory: results of a prospective study.

    Peña, Alexia S; Doherty, Dorota A; Atkinson, Helen C; Hickey, Martha; Norman, Robert J; Hart, Roger

    2018-03-01

    While ovulation is most likely to occur in adolescent girls with regular menstrual cycles, there are limited data on the incidence of ovulation in girls with irregular menstrual cycles in early postmenarcheal years. The aim of the study was to evaluate the presence of ovulation in healthy postmenarcheal girls with irregular menstrual cycles. Prospective cohort study over 12 weeks including 40 healthy postmenarcheal girls recruited from the population-based cohort of adolescents from Western Australian Pregnancy Cohort (Raine) Study with irregular menstrual cycles defined by either menstrual cycles 35 days in duration or cycle length that varied from month to month by >4 days according to menstrual diaries. Ovulation defined by urinary pregnanediol-3α-glucuronide/creatinine measurements higher than three times above minimum value obtained from 12 samples (1 per week). Forty girls (37 Caucasians) with irregular menstrual cycles aged 15.1 (median (IQR) 14.9-15.4) years who were 2.3 (1.9-3.3) years postmenarche were assessed. Urinary pregnanediol-3α-glucuronide/creatinine values identified that 33 girls (82.5%) ovulated during the 3 months of observation and 7 girls had anovulatory cycles. Menstrual diaries collected for a median (IQR) of 159 (137.5-188.2) days showed median minimal and maximum menstrual cycle duration of 24 (11.5-29) and 38.5 (35-48) days, respectively. A large proportion of healthy adolescent girls with irregular menstrual cycles are still ovulating despite irregular and infrequent menses. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  19. Post-ovulatory contraception.

    Glasier, A; Baird, D T

    1990-06-01

    It is possible to prevent pregnancy after unprotected intercourse by suppressing ovulation, inhibiting fertilization or interfering with tubal transport and/or implantation of the early embryo. IUCDs probably prevent implantation by stimulating the release of prostaglandins from the endometrium but are not acceptable to many women. Post-coital contraceptive steroids, e.g. high-dose oestrogens, are associated with a relatively high incidence of side-effects and must be taken within 72 hours of coitus. As these agents are effective by creating a uterine environment unfavourable for implantation, it may be possible to use antigestagens or antioestrogens in this way. It is already known that an antigestagen in combination with a prostaglandin is a highly effective method of inducing abortion in very early pregnancy. The corpus luteum is essential for the maintenance of pregnancy and its destruction by a luteolytic agent should dislodge the implanting embryo. If an effective method of preventing implantation could be developed which was relatively free from side-effects, it should be possible to use it as a regular form of contraception to be taken only when the risk of pregnancy had occurred.

  20. Defect grating modes as superimposed grating states

    van Groesen, Embrecht W.C.; Sopaheluwakan, A.; Andonowati, A.; de Ridder, R.M; de Ridder, R.M.; Altena, G; Altena, G.; Geuzebroek, D.H.; Geuzenboek, D.; Dekker, R.; Dekker, R

    2003-01-01

    For a symmetric grating structure with a defect, we show that a fully transmitted defect mode in the band gap can be obtained as a superposition of two steady states: an amplified and an attenuated defect state. Without scanning the whole band gap by transmission calculations, this simplifies the

  1. Topological defects in open string field theory

    Kojita, Toshiko; Maccaferri, Carlo; Masuda, Toru; Schnabl, Martin

    2018-04-01

    We show how conformal field theory topological defects can relate solutions of open string field theory for different boundary conditions. To this end we generalize the results of Graham and Watts to include the action of defects on boundary condition changing fields. Special care is devoted to the general case when nontrivial multiplicities arise upon defect action. Surprisingly the fusion algebra of defects is realized on open string fields only up to a (star algebra) isomorphism.

  2. Facts about Birth Defects

    ... label> Information For… Media Policy Makers Facts about Birth Defects Language: English (US) Español (Spanish) Recommend on ... having a baby born without a birth defect. Birth Defects Are Common Every 4 ½ minutes, a ...

  3. Neural Tube Defects

    Neural tube defects are birth defects of the brain, spine, or spinal cord. They happen in the ... that she is pregnant. The two most common neural tube defects are spina bifida and anencephaly. In ...

  4. Gene expression profiling of upregulated mRNAs in granulosa cells of bovine ovulatory follicles following stimulation with hCG

    Jacques G. Lussier

    2017-11-01

    Full Text Available Abstract Background Ovulation and luteinization of follicles are complex biological processes initiated by the preovulatory luteinizing hormone surge. The objective of this study was to identify genes that are differentially expressed in bovine granulosa cells (GC of ovulatory follicles. Methods Granulosa cells were collected during the first follicular wave of the bovine estrous cycle from dominant follicles (DF and from ovulatory follicles (OF obtained 24 h following injection of human chorionic gonadotropin (hCG. A granulosa cell subtracted cDNA library (OF-DF was generated using suppression subtractive hybridization and screened. Results Detection of genes known to be upregulated in bovine GC during ovulation, such as ADAMTS1, CAV1, EGR1, MMP1, PLAT, PLA2G4A, PTGES, PTGS2, RGS2, TIMP1, TNFAIP6 and VNN2 validated the physiological model and analytical techniques used. For a subset of genes that were identified for the first time, gene expression profiles were further compared by semiquantitative RT-PCR in follicles obtained at different developmental stages. Results confirmed an induction or upregulation of the respective mRNAs in GC of OF 24 h after hCG-injection compared with those of DF for the following genes: ADAMTS9, ARAF, CAPN2, CRISPLD2, FKBP5, GFPT2, KIT, KITLG, L3MBLT3, MRO, NUDT10, NUDT11, P4HA3, POSTN, PSAP, RBP1, SAT1, SDC4, TIMP2, TNC and USP53. In bovine GC, CRISPLD2 and POSTN mRNA were found as full-length transcript whereas L3MBLT3 mRNA was alternatively spliced resulting in a truncated protein missing the carboxy-terminal end amino acids, 774KNSHNEL780. Conversely, L3MBLT3 is expressed as a full-length mRNA in a bovine endometrial cell line. The 774KNSHNEL780 sequence is well conserved in all mammalian species and follows a SAM domain known to confer protein/protein interactions, which suggest a key function for these amino acids in the epigenetic control of gene expression. Conclusions We conclude that we have identified

  5. Benign gastric filling defect

    Oh, K. K.; Lee, Y. H.; Cho, O. K.; Park, C. Y.

    1979-01-01

    The gastric lesion is a common source of complaints to Orientals, however, evaluation of gastric symptoms and laboratory examination offer little specific aid in the diagnosis of gastric diseases. Thus roentgenography of gastrointestinal tract is one of the most reliable method for detail diagnosis. On double contract study of stomach, gastric filling defect is mostly caused by malignant gastric cancer, however, other benign lesions can cause similar pictures which can be successfully treated by surgery. 66 cases of benign causes of gastric filling defect were analyzed at this point of view, which was verified pathologically by endoscope or surgery during recent 7 years in Yensei University College of Medicine, Severance Hospital. The characteristic radiological picture of each disease was discussed for precise radiologic diagnosis. 1. Of total 66 cases, there were 52 cases of benign gastric tumor 10 cases of gastric varices, 5 cases of gastric bezoar, 5 cases of corrosive gastritis, 3 cases of granulomatous disease and one case of gastric hematoma. 2. The most frequent causes of benign tumors were adenomatous polyp (35/42) and the next was leiomyoma (4/42). Others were one of case of carcinoid, neurofibroma and cyst. 3. Characteristic of benign adenomatous polyp were relatively small in size, smooth surface and were observed that large size, benign polyp was frequently type IV lesion with a stalk. 4. Submucosal tumors such as leiomyoma needed differential diagnosis with polypoid malignant cancer. However, the characteristic points of differentiation was well circumscribed smooth margined filling defect without definite mucosal destruction on surface. 5. Gastric varices showed multiple lobulated filling defected especially on gastric fundus that changed its size and shape by respiration and posture of patients. Same varices lesions on esophagus and history of liver disease were helpful for easier diagnosis. 6. Gastric bezoar showed well defined movable mass

  6. Benign gastric filling defect

    Oh, K. K.; Lee, Y. H.; Cho, O. K.; Park, C. Y. [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    1979-06-15

    The gastric lesion is a common source of complaints to Orientals, however, evaluation of gastric symptoms and laboratory examination offer little specific aid in the diagnosis of gastric diseases. Thus roentgenography of gastrointestinal tract is one of the most reliable method for detail diagnosis. On double contract study of stomach, gastric filling defect is mostly caused by malignant gastric cancer, however, other benign lesions can cause similar pictures which can be successfully treated by surgery. 66 cases of benign causes of gastric filling defect were analyzed at this point of view, which was verified pathologically by endoscope or surgery during recent 7 years in Yensei University College of Medicine, Severance Hospital. The characteristic radiological picture of each disease was discussed for precise radiologic diagnosis. 1. Of total 66 cases, there were 52 cases of benign gastric tumor 10 cases of gastric varices, 5 cases of gastric bezoar, 5 cases of corrosive gastritis, 3 cases of granulomatous disease and one case of gastric hematoma. 2. The most frequent causes of benign tumors were adenomatous polyp (35/42) and the next was leiomyoma (4/42). Others were one of case of carcinoid, neurofibroma and cyst. 3. Characteristic of benign adenomatous polyp were relatively small in size, smooth surface and were observed that large size, benign polyp was frequently type IV lesion with a stalk. 4. Submucosal tumors such as leiomyoma needed differential diagnosis with polypoid malignant cancer. However, the characteristic points of differentiation was well circumscribed smooth margined filling defect without definite mucosal destruction on surface. 5. Gastric varices showed multiple lobulated filling defected especially on gastric fundus that changed its size and shape by respiration and posture of patients. Same varices lesions on esophagus and history of liver disease were helpful for easier diagnosis. 6. Gastric bezoar showed well defined movable mass

  7. Benign gastric filling defect

    Oh, K K; Lee, Y H; Cho, O K; Park, C Y [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    1979-06-15

    The gastric lesion is a common source of complaints to Orientals, however, evaluation of gastric symptoms and laboratory examination offer little specific aid in the diagnosis of gastric diseases. Thus roentgenography of gastrointestinal tract is one of the most reliable method for detail diagnosis. On double contract study of stomach, gastric filling defect is mostly caused by malignant gastric cancer, however, other benign lesions can cause similar pictures which can be successfully treated by surgery. 66 cases of benign causes of gastric filling defect were analyzed at this point of view, which was verified pathologically by endoscope or surgery during recent 7 years in Yensei University College of Medicine, Severance Hospital. The characteristic radiological picture of each disease was discussed for precise radiologic diagnosis. 1. Of total 66 cases, there were 52 cases of benign gastric tumor 10 cases of gastric varices, 5 cases of gastric bezoar, 5 cases of corrosive gastritis, 3 cases of granulomatous disease and one case of gastric hematoma. 2. The most frequent causes of benign tumors were adenomatous polyp (35/42) and the next was leiomyoma (4/42). Others were one of case of carcinoid, neurofibroma and cyst. 3. Characteristic of benign adenomatous polyp were relatively small in size, smooth surface and were observed that large size, benign polyp was frequently type IV lesion with a stalk. 4. Submucosal tumors such as leiomyoma needed differential diagnosis with polypoid malignant cancer. However, the characteristic points of differentiation was well circumscribed smooth margined filling defect without definite mucosal destruction on surface. 5. Gastric varices showed multiple lobulated filling defected especially on gastric fundus that changed its size and shape by respiration and posture of patients. Same varices lesions on esophagus and history of liver disease were helpful for easier diagnosis. 6. Gastric bezoar showed well defined movable mass

  8. Electrical fingerprint of pipeline defects

    Mica, Isabella; Polignano, Maria Luisa; Marco, Cinzia De

    2004-01-01

    Pipeline defects are dislocations that connect the source region of the transistor with the drain region. They were widely reported to occur in CMOS, BiCMOS devices and recently in SOI technologies. They can reduce device yield either by affecting the devices functionality or by increasing the current consumption under stand-by conditions. In this work the electrical fingerprint of these dislocations is studied, its purpose is to enable us to identify these defects as the ones responsible for device failure. It is shown that the pipeline defects are responsible for a leakage current from source to drain in the transistors. This leakage has a resistive characteristic and it is lightly modulated by the body bias. It is not sensitive to temperature; vice versa the off-current of a good transistor exhibits the well-known exponential dependence on 1/T. The emission spectrum of these defects was studied and compared with the spectrum of a good transistor. The paper aims to show that the spectrum of a defective transistor is quite peculiar; it shows well defined peaks, whereas the spectrum of a good transistor under saturation conditions is characterized by a broad spectral light emission distribution. Finally the deep-level transient spectroscopy (DLTS) is tried on defective diodes

  9. Defect detection based on extreme edge of defective region histogram

    Zouhir Wakaf

    2018-01-01

    Full Text Available Automatic thresholding has been used by many applications in image processing and pattern recognition systems. Specific attention was given during inspection for quality control purposes in various industries like steel processing and textile manufacturing. Automatic thresholding problem has been addressed well by the commonly used Otsu method, which provides suitable results for thresholding images based on a histogram of bimodal distribution. However, the Otsu method fails when the histogram is unimodal or close to unimodal. Defects have different shapes and sizes, ranging from very small to large. The gray-level distributions of the image histogram can vary between unimodal and multimodal. Furthermore, Otsu-revised methods, like the valley-emphasis method and the background histogram mode extents, which overcome the drawbacks of the Otsu method, require preprocessing steps and fail to use the general threshold for multimodal defects. This study proposes a new automatic thresholding algorithm based on the acquisition of the defective region histogram and the selection of its extreme edge as the threshold value to segment all defective objects in the foreground from the image background. To evaluate the proposed defect-detection method, common standard images for experimentation were used. Experimental results of the proposed method show that the proposed method outperforms the current methods in terms of defect detection.

  10. Craniotomy Frontal Bone Defect

    2018-03-01

    Mar 1, 2018 ... Defect reconstruction and fixation of the graft: The defect of ... where all loose fragments of fractured frontal bone was removed via the ... Mandible. • Ilium. • Allograft ... pediatric patients owing to skull growth. Thus, autologous ...

  11. Congenital platelet function defects

    ... pool disorder; Glanzmann's thrombasthenia; Bernard-Soulier syndrome; Platelet function defects - congenital ... Congenital platelet function defects are bleeding disorders that cause reduced platelet function. Most of the time, people with these disorders have ...

  12. Defect of the Eyelids.

    Lu, Guanning Nina; Pelton, Ron W; Humphrey, Clinton D; Kriet, John David

    2017-08-01

    Eyelid defects disrupt the complex natural form and function of the eyelids and present a surgical challenge. Detailed knowledge of eyelid anatomy is essential in evaluating a defect and composing a reconstructive plan. Numerous reconstructive techniques have been described, including primary closure, grafting, and a variety of local flaps. This article describes an updated reconstructive ladder for eyelid defects that can be used in various permutations to solve most eyelid defects. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Point defects in solids

    Anon.

    1978-01-01

    The principal properties of point defects are studied: thermodynamics, electronic structure, interactions with etended defects, production by irradiation. Some measuring methods are presented: atomic diffusion, spectroscopic methods, diffuse scattering of neutron and X rays, positron annihilation, molecular dynamics. Then points defects in various materials are investigated: ionic crystals, oxides, semiconductor materials, metals, intermetallic compounds, carbides, nitrides [fr

  14. Fibrous metaphyseal defects

    Ritschl, P.; Hajek, P.C.; Pechmann, U.

    1989-01-01

    Sixteen patients with fibrous metaphyseal defects were examined with both plain radiography and magnetic resonance (MR) imaging. Depending on the age of the fibrous metaphyseal defects, characteristic radiomorphologic changes were found which correlated well with MR images. Following intravenous Gadolinium-DTPA injection, fibrous metaphyseal defects invariably exhibited a hyperintense border and signal enhancement. (orig./GDG)

  15. Birth Defects (For Parents)

    ... Staying Safe Videos for Educators Search English Español Birth Defects KidsHealth / For Parents / Birth Defects What's in ... Prevented? Print en español Anomalías congénitas What Are Birth Defects? While still in the womb, some babies ...

  16. Effects of mass defect in atomic clocks

    Taichenachev, A. V.; Yudin, V. I.

    2018-01-01

    We consider some implications of the mass defect on the frequency of atomic transitions. We have found that some well-known frequency shifts (such as gravitational and quadratic Doppler shifts) can be interpreted as consequences of the mass defect, i.e., without the need for the concept of time dilation used in special and general relativity theories. Moreover, we show that the inclusion of the mass defect leads to previously unknown shifts for clocks based on trapped ions..

  17. Effect of bovine somatotropin (500 mg) administered at ten-day intervals on ovulatory responses, expression of estrus, and fertility in dairy cows.

    Rivera, F; Narciso, C; Oliveira, R; Cerri, R L A; Correa-Calderón, A; Chebel, R C; Santos, J E P

    2010-04-01

    The objectives of this study were to evaluate the effect of administering 500 mg of recombinant bovine somatotropin (bST) every 10 d on ovulatory responses, estrous behavior, and fertility of lactating Holstein cows. Lactating dairy cows were assigned to 1 of 2 treatments: a control with no administration of bST (73 primiparous and 120 multiparous cows) or 6 consecutive administrations of 500 mg of bST (83 primiparous and 123 multiparous cows) given subcutaneously at 10-d intervals starting 61+/-3 d postpartum (study d 0), concurrent with the initiation of the timed artificial insemination (AI). Blood samples were collected thrice weekly from 61+/-3 to 124+/-3 d in milk (DIM), and plasma samples were analyzed for concentrations of estradiol, glucose, insulin, insulin-like growth factor 1, and progesterone. The estrous cycle of cows was presynchronized with 2 injections of PGF(2alpha) at 37+/-3 and 51+/-3 DIM, and the Ovsynch timed AI protocol was initiated at 61+/-3 DIM. Ovaries were scanned to determine ovulatory responses during the Ovsynch protocol. Pregnancy was diagnosed at 33 and 66 d after AI. Body condition was scored on study d 0, 10, 42, and 76. Sixty-four cows were fitted with a pressure mounting sensor with radiotelemetric transmitters to monitor estrous behavior. Treatment of lactating dairy cows with 500 mg of bST at 10-d intervals increased yields of milk and milk components in the first 2 mo after treatment. Body condition of bST-treated cows remained unaltered, whereas control cows gained BCS. Treatment with bST increased concentrations of insulin-like growth factor 1 chronically, but concentrations of insulin and glucose increased only transiently in the first 7 d after the first injection of bST. Concentrations of progesterone during and after the Ovsynch protocol remained unaltered after treatment with bST; likewise, ovulatory responses during the Ovsynch protocol were mostly unaltered by treatment. Concentration of estradiol tended to be

  18. Dirichlet topological defects

    Carroll, S.M.; Trodden, M.

    1998-01-01

    We propose a class of field theories featuring solitonic solutions in which topological defects can end when they intersect other defects of equal or higher dimensionality. Such configurations may be termed open-quotes Dirichlet topological defects,close quotes in analogy with the D-branes of string theory. Our discussion focuses on defects in scalar field theories with either gauge or global symmetries, in 3+1 dimensions; the types of defects considered include walls ending on walls, strings on walls, and strings on strings. copyright 1998 The American Physical Society

  19. Defect production in ceramics

    Zinkle, S.J. [Oak Ridge National Lab., TN (United States); Kinoshita, C. [Kyushu Univ. (Japan)

    1997-08-01

    A review is given of several important defect production and accumulation parameters for irradiated ceramics. Materials covered in this review include alumina, magnesia, spinel silicon carbide, silicon nitride, aluminum nitride and diamond. Whereas threshold displacement energies for many ceramics are known within a reasonable level of uncertainty (with notable exceptions being AIN and Si{sub 3}N{sub 4}), relatively little information exists on the equally important parameters of surviving defect fraction (defect production efficiency) and point defect migration energies for most ceramics. Very little fundamental displacement damage information is available for nitride ceramics. The role of subthreshold irradiation on defect migration and microstructural evolution is also briefly discussed.

  20. A proposed defect tracking model for classifying the inserted defect reports to enhance software quality control.

    Sultan, Torky; Khedr, Ayman E; Sayed, Mostafa

    2013-01-01

    NONE DECLARED Defect tracking systems play an important role in the software development organizations as they can store historical information about defects. There are many research in defect tracking models and systems to enhance their capabilities to be more specifically tracking, and were adopted with new technology. Furthermore, there are different studies in classifying bugs in a step by step method to have clear perception and applicable method in detecting such bugs. This paper shows a new proposed defect tracking model for the purpose of classifying the inserted defects reports in a step by step method for more enhancement of the software quality.

  1. Replacing single frozen-thawed euploid embryos in a natural cycle in ovulatory women may increase live birth rates compared to medicated cycles in anovulatory women.

    Melnick, Alexis P; Setton, Robert; Stone, Logan D; Pereira, Nigel; Xu, Kangpu; Rosenwaks, Zev; Spandorfer, Steven D

    2017-10-01

    The goal of this study was to compare pregnancy outcomes between natural frozen embryo transfer (FET) cycles in ovulatory women and programmed FET cycles in anovulatory women after undergoing in vitro fertilization with preimplantation genetic screening (IVF-PGS). This was a retrospective cohort study performed at an academic medical center. Patients undergoing single FET IVF-PGS cycles between October 2011 and December 2014 were included. Patients were stratified by type of endometrial replacement: programmed cycles with estrogen/progesterone replacement and natural cycles. IVF-PGS with 24-chromosome screening was performed on all included patients. Those patients with euploid embryos had single embryo transfer in a subsequent FET. The primary study outcome was live birth/ongoing pregnancy rate. Secondary outcomes included implantation, biochemical pregnancy, and miscarriage rates. One hundred thirteen cycles met inclusion criteria: 65 natural cycles and 48 programmed cycles. The programmed FET group was younger (35.9 ± 4.5 vs. 37.5 ± 3.7, P = 0.03) and had a higher AMH (3.95 ± 4.2 vs. 2.37 ± 2.4, P = 0.045). The groups were similar for BMI, gravidity, parity, history of uterine surgery, and incidence of Asherman's syndrome. There was also no difference in embryo grade at biopsy or transfer, and proportion of day 5 and day 6 transfers. Implantation rates were higher in the natural FET group (0.66 ± 0.48 vs. 0.44 ± 0.50, P = 0.02). There was no difference in the rates of biochemical pregnancy or miscarriage. After controlling for age, live birth/ongoing pregnancy rate was higher in natural FETs with an adjusted odds ratio of 2.68 (95% CI 1.22-5.87). Natural FET in ovulatory women after IVF-PGS is associated with increased implantation and live birth rates compared to programmed FET in anovulatory women. Further investigation is needed to determine whether these findings hold true in other patient cohorts.

  2. On holographic defect entropy

    Estes, John; Jensen, Kristan; O’Bannon, Andy; Tsatis, Efstratios; Wrase, Timm

    2014-01-01

    We study a number of (3+1)- and (2+1)-dimensional defect and boundary conformal field theories holographically dual to supergravity theories. In all cases the defects or boundaries are planar, and the defects are codimension-one. Using holography, we compute the entanglement entropy of a (hemi-)spherical region centered on the defect (boundary). We define defect and boundary entropies from the entanglement entropy by an appropriate background subtraction. For some (3+1)-dimensional theories we find evidence that the defect/boundary entropy changes monotonically under certain renormalization group flows triggered by operators localized at the defect or boundary. This provides evidence that the g-theorem of (1+1)-dimensional field theories generalizes to higher dimensions

  3. Dual approaches for defects condensation

    Rougemont, Romulo; Grigorio, Leonardo de Souza; Wotzasek, Clovis [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Guimaraes, Marcelo Santos [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil)

    2009-07-01

    Full text. Due to the fact that the QCD running coupling constant becomes larger as we go into the low energy (or large distance) limit of the theory, a perturbative treatment of its infrared (IR) region is impossible. In particular, a formal mathematical demonstration of color confinement and a complete physical understanding of the exact mechanism that confines quarks and gluons are two missing points in our current knowledge of the IR-QCD. It was known that due to the Meissner effect of expulsion of magnetic fields in a electric condensate that usual superconductors should confine magnetic monopoles. That point led to the conjecture that the QCD vacuum could be a condensate of chromomagnetic monopoles, a dual superconductor (DSC). Such a chromomagnetic condensate should be responsible for the dual Meissner effect which is expected to lead to the confinement of color charges immersed in this medium. In dual superconductor models of color confinement, magnetic monopoles appear as topological defects in points of the space where the abelian projection becomes singular. Also, condensation of other kinds of defects such as vortices in superfluids and line-like defects in solids are responsible for a great variety of phase transitions, which once more proves the relevance of the subject. In the present work we review two methods that allow us to approach the condensation of defects: the Kleinert Mechanism (KM) and the Julia-Toulouse Mechanism (JTM). We show that in the limit where the vortex gauge field goes to zero, which we identify as the signature of the condensation of defects in the dual picture, these are two equivalent dual prescriptions for obtaining an effective theory for a phase where defects are condensed, starting from the fundamental theory defined in the normal phase where defects are diluted. (author)

  4. Genital and Urinary Tract Defects

    ... conditions > Genital and urinary tract defects Genital and urinary tract defects E-mail to a friend Please fill ... and extra fluids. What problems can genital and urinary tract defects cause? Genital and urinary tract defects affect ...

  5. Automatic classification of defects in weld pipe

    Anuar Mikdad Muad; Mohd Ashhar Hj Khalid; Abdul Aziz Mohamad; Abu Bakar Mhd Ghazali; Abdul Razak Hamzah

    2000-01-01

    With the advancement of computer imaging technology, the image on hard radiographic film can be digitized and stored in a computer and the manual process of defect recognition and classification may be replace by the computer. In this paper a computerized method for automatic detection and classification of common defects in film radiography of weld pipe is described. The detection and classification processes consist of automatic selection of interest area on the image and then classify common defects using image processing and special algorithms. Analysis of the attributes of each defect such as area, size, shape and orientation are carried out by the feature analysis process. These attributes reveal the type of each defect. These methods of defect classification result in high success rate. Our experience showed that sharp film images produced better results

  6. Altering graphene line defect properties using chemistry

    Vasudevan, Smitha; White, Carter; Gunlycke, Daniel

    2012-02-01

    First-principles calculations are presented of a fundamental topological line defect in graphene that was observed and reported in Nature Nanotech. 5, 326 (2010). These calculations show that atoms and smaller molecules can bind covalently to the surface in the vicinity of the graphene line defect. It is also shown that the chemistry at the line defect has a strong effect on its electronic and magnetic properties, e.g. the ferromagnetically aligned moments along the line defect can be quenched by some adsorbates. The strong effect of the adsorbates on the line defect properties can be understood by examining how these adsorbates affect the boundary-localized states in the vicinity of the Fermi level. We also expect that the line defect chemistry will significantly affect the scattering properties of incident low-energy particles approaching it from graphene.

  7. Automatic classification of defects in weld pipe

    Anuar Mikdad Muad; Mohd Ashhar Khalid; Abdul Aziz Mohamad; Abu Bakar Mhd Ghazali; Abdul Razak Hamzah

    2001-01-01

    With the advancement of computer imaging technology, the image on hard radiographic film can be digitized and stored in a computer and the manual process of defect recognition and classification may be replaced by the computer. In this paper, a computerized method for automatic detection and classification of common defects in film radiography of weld pipe is described. The detection and classification processes consist of automatic selection of interest area on the image and then classify common defects using image processing and special algorithms. Analysis of the attributes of each defect such area, size, shape and orientation are carried out by the feature analysis process. These attributes reveal the type of each defect. These methods of defect classification result in high success rate. Our experience showed that sharp film images produced better results. (Author)

  8. Detection of paint polishing defects

    Rebeggiani, S.; Wagner, M.; Mazal, J.; Rosén, B.-G.; Dahlén, M.

    2018-06-01

    Surface finish plays a major role on perceived product quality, and is the first thing a potential buyer sees. Today end-of-line repairs of the body of cars and trucks are inevitably to secure required surface quality. Defects that occur in the paint shop, like dust particles, are eliminated by manual sanding/polishing which lead to other types of defects when the last polishing step is not performed correctly or not fully completed. One of those defects is known as ‘polishing roses’ or holograms, which are incredibly hard to detect in artificial light but are clearly visible in sunlight. This paper will present the first tests with a measurement set-up newly developed to measure and analyse polishing roses. The results showed good correlations to human visual evaluations where repaired panels were estimated based on the defects’ intensity, severity and viewing angle.

  9. Show-Bix &

    2014-01-01

    The anti-reenactment 'Show-Bix &' consists of 5 dias projectors, a dial phone, quintophonic sound, and interactive elements. A responsive interface will enable the Dias projectors to show copies of original dias slides from the Show-Bix piece ”March på Stedet”, 265 images in total. The copies are...

  10. The effect of dietary protein on reproduction in the mare. III. Ovarian and uterine changes during the anovulatory, transitional and ovulatory periods in the non-pregnant mare

    F.E. Van Niekerk

    1997-07-01

    Full Text Available In the main experiment the total daily protein intake and quality (essential amino-acids was varied in 4 groups of mares. The incidence of oestrus in mares during the transitional period was unaffected by protein nutrition. Ovarian activity, as evaluated by follicular development and size of the ovaries, was affected. Mares that received low-quality protein (Groups 1 and 2 had a higher number of smaller follicles (<10 mm that developed during the transitional period compared to mares on a high-quality protein intake (Groups 3 and 4. The mares that received the high quality protein ovulated 2-3 weeks earlier in the breeding season in a synchronised period of 4-5 weeks compared to a period of 6-8 weeks in Groups 1 and 2. The duration of the subsequent oestrous cycles was not affected. There was no difference in the diameter of the largest follicle of mares between groups on the day before ovulation. In a separate experiment, 5 maiden Anglo-Arab mares, 4-5 years of age, were slaughtered at different stages during the anovulatory, transitional and ovulatory periods of the breeding cycle. The morphology of the ovaries and uteri of these mares was described and photographed for use as guidelines when comparing ovarian changes and follicular activity of mares.

  11. Frozen-thawed embryo transfer in a natural or mildly hormonally stimulated cycle in women with regular ovulatory cycles: a RCT.

    Peeraer, Karen; Couck, Isabelle; Debrock, Sophie; De Neubourg, Diane; De Loecker, Peter; Tomassetti, Carla; Laenen, Annouschka; Welkenhuysen, Myriam; Meeuwis, Luc; Pelckmans, Sofie; Meuleman, Christel; D'Hooghe, Thomas

    2015-11-01

    Can ovarian stimulation with low dose hMG improve the implantation rate (IR) per frozen-thawed embryo transferred (FET) when compared with natural cycle in an FET programme in women with a regular ovulatory cycle? Both IR and live birth rate (LBR) per FET were similar in the group with mild ovarian stimulation and the natural cycle group. Different cycle regimens for endometrial preparation are used prior to FET: spontaneous ovulatory cycles, cycles with artificial endometrial preparation using estrogen and progesterone hormones, and cycles stimulated with gonadotrophins or clomiphene citrate. At present, it is not clear which regimen results in the highest IR or LBR. More specifically, there are no RCTs in ovulatory women comparing reproductive outcome after FET during a natural cycle and during a hormonally stimulated cycle. A total of 410 women scheduled for FET during 579 cycles (December 2003-September 2013) were enrolled in an open-label RCT to natural cycle (NC FET group, n = 291) or to a cycle hormonally stimulated with s.c. gonadotrophins (hMG FET group, 37.5-75 IU per day, n = 288). A total of 672 embryos were transferred during 434 cycles (332 embryos and 213 cycles in the NC FET group; 340 embryos and 221 cycles in the hMG FET group). Assuming a = 0.05 and 80% power, it was calculated that 219 frozen-thawed embryos were required for transfer in each group to demonstrate a difference of 10% in IR. Women were eligible according to the following inclusion criteria: regular ovulatory cycle, female age ≥21 years and ≤45 years, informed consent. FET cycles with preimplantation genetic screening were excluded. The primary outcome was IR per embryo transferred. Secondary outcomes included IR with fetal heart beat (FHB), LBR per embryo transferred and endometrial thickness on the day of hCG administration. Statistical analysis was by intention to treat and controlled for the presence of multiple measures, as eligible women could be randomized in more than

  12. Defect structure of electrodeposited chromium layers

    Marek, T.; Suevegh, K.; Vertes, A.; El-Sharif, M.; McDougall, J.; Chisolm, C.U.

    2000-01-01

    Positron annihilation spectroscopy was applied to study the effects of pre-treatment and composition of substrates on the quality and defect structure of electrodeposited thick chromium coatings. The results show that both parameters are important, and a scenario is proposed why the mechanically polished substrate gives more defective film than the electro polished one.

  13. Defect structure of electrodeposited chromium layers

    Marek, T. E-mail: marek@para.chem.elte.hu; Suevegh, K.; Vertes, A.; El-Sharif, M.; McDougall, J.; Chisolm, C.U

    2000-06-01

    Positron annihilation spectroscopy was applied to study the effects of pre-treatment and composition of substrates on the quality and defect structure of electrodeposited thick chromium coatings. The results show that both parameters are important, and a scenario is proposed why the mechanically polished substrate gives more defective film than the electro polished one.

  14. Defects in semiconductors

    Romano, Lucia; Jagadish, Chennupati

    2015-01-01

    This volume, number 91 in the Semiconductor and Semimetals series, focuses on defects in semiconductors. Defects in semiconductors help to explain several phenomena, from diffusion to getter, and to draw theories on materials' behavior in response to electrical or mechanical fields. The volume includes chapters focusing specifically on electron and proton irradiation of silicon, point defects in zinc oxide and gallium nitride, ion implantation defects and shallow junctions in silicon and germanium, and much more. It will help support students and scientists in their experimental and theoret

  15. Defect spectroscopy of single ZnO microwires

    Villafuerte, M.; Ferreyra, J. M.; Zapata, C.; Barzola-Quiquia, J.; Iikawa, F.; Esquinazi, P.; Heluani, S. P.; de Lima, M. M.; Cantarero, A.

    2014-04-01

    The point defects of single ZnO microwires grown by carbothermal reduction were studied by microphotoluminescence, photoresistance excitation spectra, and resistance as a function of the temperature. We found the deep level defect density profile along the microwire showing that the concentration of defects decreases from the base to the tip of the microwires and this effect correlates with a band gap narrowing. The results show a characteristic deep defect levels inside the gap at 0.88 eV from the top of the VB. The resistance as a function of the temperature shows defect levels next to the bottom of the CB at 110 meV and a mean defect concentration of 4 × 1018 cm-3. This combination of techniques allows us to study the band gap values and defects states inside the gap in single ZnO microwires and opens the possibility to be used as a defect spectroscopy method.

  16. Metallography of defects

    Borisova, E.A.; Bochvar, G.A.; Brun, M.Ya.

    1980-01-01

    Different types of defects of metallurgical, technological and exploitation origin in intermediate and final products of titanium alloys, are considered. The examples of metallic and nonmetallic inclusions, chemical homogeneity, different grains, bands, cracks, places of searing, porosity are given; methods of detecting the above defects are described. The methods of metallography, X-ray spectral analysis, measuring microhardness are used

  17. Beating Birth Defects

    Each year in the U.S., one in 33 babies is affected by a major birth defect. Women can greatly improve their chances of giving birth to a healthy baby by avoiding some of the risk factors for birth defects before and during pregnancy. In this podcast, Dr. Stuart Shapira discusses ways to improve the chances of giving birth to a healthy baby.

  18. Talking with TV shows

    Sandvik, Kjetil; Laursen, Ditte

    2014-01-01

    User interaction with radio and television programmes is not a new thing. However, with new cross-media production concepts such as X Factor and Voice, this is changing dramatically. The second-screen logic of these productions encourages viewers, along with TV’s traditional one-way communication...... mode, to communicate on interactive (dialogue-enabling) devices such as laptops, smartphones and tablets. Using the TV show Voice as our example, this article shows how the technological and situational set-up of the production invites viewers to engage in new ways of interaction and communication...

  19. Defects at oxide surfaces

    Thornton, Geoff

    2015-01-01

    This book presents the basics and characterization of defects at oxide surfaces. It provides a state-of-the-art review of the field, containing information to the various types of surface defects, describes analytical methods to study defects, their chemical activity and the catalytic reactivity of oxides. Numerical simulations of defective structures complete the picture developed. Defects on planar surfaces form the focus of much of the book, although the investigation of powder samples also form an important part. The experimental study of planar surfaces opens the possibility of applying the large armoury of techniques that have been developed over the last half-century to study surfaces in ultra-high vacuum. This enables the acquisition of atomic level data under well-controlled conditions, providing a stringent test of theoretical methods. The latter can then be more reliably applied to systems such as nanoparticles for which accurate methods of characterization of structure and electronic properties ha...

  20. Defects in dilute nitrides

    Chen, W.M.; Buyanova, I.A.; Tu, C.W.; Yonezu, H.

    2005-01-01

    We provide a brief review our recent results from optically detected magnetic resonance studies of grown-in non-radiative defects in dilute nitrides, i.e. Ga(In)NAs and Ga(Al,In)NP. Defect complexes involving intrinsic defects such as As Ga antisites and Ga i self interstitials were positively identified.Effects of growth conditions, chemical compositions and post-growth treatments on formation of the defects are closely examined. These grown-in defects are shown to play an important role in non-radiative carrier recombination and thus in degrading optical quality of the alloys, harmful to performance of potential optoelectronic and photonic devices based on these dilute nitrides. (author)

  1. Talk Show Science.

    Moore, Mitzi Ruth

    1992-01-01

    Proposes having students perform skits in which they play the roles of the science concepts they are trying to understand. Provides the dialog for a skit in which hot and cold gas molecules are interviewed on a talk show to study how these properties affect wind, rain, and other weather phenomena. (MDH)

  2. Obesity in show cats.

    Corbee, R J

    2014-12-01

    Obesity is an important disease with a high prevalence in cats. Because obesity is related to several other diseases, it is important to identify the population at risk. Several risk factors for obesity have been described in the literature. A higher incidence of obesity in certain cat breeds has been suggested. The aim of this study was to determine whether obesity occurs more often in certain breeds. The second aim was to relate the increased prevalence of obesity in certain breeds to the official standards of that breed. To this end, 268 cats of 22 different breeds investigated by determining their body condition score (BCS) on a nine-point scale by inspection and palpation, at two different cat shows. Overall, 45.5% of the show cats had a BCS > 5, and 4.5% of the show cats had a BCS > 7. There were significant differences between breeds, which could be related to the breed standards. Most overweight and obese cats were in the neutered group. It warrants firm discussions with breeders and cat show judges to come to different interpretations of the standards in order to prevent overweight conditions in certain breeds from being the standard of beauty. Neutering predisposes for obesity and requires early nutritional intervention to prevent obese conditions. Journal of Animal Physiology and Animal Nutrition © 2014 Blackwell Verlag GmbH.

  3. Honored Teacher Shows Commitment.

    Ratte, Kathy

    1987-01-01

    Part of the acceptance speech of the 1985 National Council for the Social Studies Teacher of the Year, this article describes the censorship experience of this honored social studies teacher. The incident involved the showing of a videotape version of the feature film entitled "The Seduction of Joe Tynan." (JDH)

  4. Defect branes as Alice strings

    Okada, Takashi; Sakatani, Yuho

    2015-01-01

    There exist various defect-brane backgrounds in supergravity theories which arise as the low energy limit of string theories. These backgrounds typically have non-trivial monodromies, and if we move a charged probe around the center of a defect, its charge will be changed by the action of the monodromy. During the process, the charge conservation law seems to be violated. In this paper, to resolve this puzzle, we examine a dynamics of the charge changing process and show that the missing charge of the probe is transferred to the background. We then explicitly construct the resultant background after the charge transfer process by utilizing dualities. This background has the same monodromy as the original defect brane, but has an additional charge which does not have any localized source. In the literature, such a charge without localized source is known to appear in the presence of Alice strings. We argue that defect branes can in fact be regarded as a realization of Alice strings in string theory and examine the charge transfer process from that perspective.

  5. Defect branes as Alice strings

    Okada, Takashi [Theoretical Biology Laboratory, RIKEN,Wako 351-0198 (Japan); Sakatani, Yuho [Department of Physics and Astronomy,Seoul National University, Seoul 151-747 (Korea, Republic of)

    2015-03-25

    There exist various defect-brane backgrounds in supergravity theories which arise as the low energy limit of string theories. These backgrounds typically have non-trivial monodromies, and if we move a charged probe around the center of a defect, its charge will be changed by the action of the monodromy. During the process, the charge conservation law seems to be violated. In this paper, to resolve this puzzle, we examine a dynamics of the charge changing process and show that the missing charge of the probe is transferred to the background. We then explicitly construct the resultant background after the charge transfer process by utilizing dualities. This background has the same monodromy as the original defect brane, but has an additional charge which does not have any localized source. In the literature, such a charge without localized source is known to appear in the presence of Alice strings. We argue that defect branes can in fact be regarded as a realization of Alice strings in string theory and examine the charge transfer process from that perspective.

  6. Molecular-dynamics simulation of defect formation energy in boron nitride nanotubes

    Moon, W.H.; Hwang, H.J.

    2004-01-01

    We investigate the defect formation energy of boron nitride nanotubes (BNNTs) using molecular dynamics simulation. Although the defect with tetragon-octagon pairs (TOP) is favored in the flat BNNTs cap, BN clusters, and the growth of BNNTs, the formation energy of the TOP defect is significantly higher than that of the pentagon-heptagon pairs (PHP) defect in BNNTs. The PHP defect reduces the effect of the structural distortion caused by the TOP defect, in spite of homoelemental bonds. The instability of the TOP defect generates the structural transformation into BNNTs with no defect at about 1500 K. This mechanism shows that the TOP defect is less favored in case of BNNTs

  7. The energy show

    1988-01-01

    The Energy Show is a new look at the problems of world energy, where our supplies come from, now and in the future. The programme looks at how we need energy to maintain our standards of living. Energy supply is shown as the complicated set of problems it is - that Fossil Fuels are both raw materials and energy sources, that some 'alternatives' so readily suggested as practical options are in reality a long way from being effective. (author)

  8. Defective Reduction in Frozen Pie Manufacturing Process

    Nooted, Oranuch; Tangjitsitcharoen, Somkiat

    2017-06-01

    The frozen pie production has a lot of defects resulting in high production cost. Failure mode and effect analysis (FMEA) technique has been applied to improve the frozen pie process. Pareto chart is also used to determine the major defects of frozen pie. There are 3 main processes that cause the defects which are the 1st freezing to glazing process, the forming process, and the folding process. The Risk Priority Number (RPN) obtained from FMEA is analyzed to reduce the defects. If RPN of each cause exceeds 45, the process will be considered to be improved and selected for the corrective and preventive actions. The results showed that RPN values decreased after the correction. Therefore, the implementation of FMEA technique can help to improve the performance of frozen pie process and reduce the defects approximately 51.9%.

  9. Full transmission modes and steady states in defect gratings,

    van Groesen, Embrecht W.C.; Sopaheluwakan, A.; Andonowati, A.; de Ridder, R.M; Altena, G; Geuzebroek, D.H.; Dekker, R

    2003-01-01

    For a symmetric grating structure with a defect, we show that a fully transmitted defect mode in the band gap can be obtained as a superposition of two steady states: an amplified and an attenuated defect state. Without scanning the whole band gap by transmission calculations, this simplifies the

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

    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

  11. Formation of topological defects

    Vachaspati, T.

    1991-01-01

    We consider the formation of point and line topological defects (monopoles and strings) from a general point of view by allowing the probability of formation of a defect to vary. To investigate the statistical properties of the defects at formation we give qualitative arguments that are independent of any particular model in which such defects occur. These arguments are substantiated by numerical results in the case of strings and for monopoles in two dimensions. We find that the network of strings at formation undergoes a transition at a certain critical density below which there are no infinite strings and the closed-string (loop) distribution is exponentially suppressed at large lengths. The results are contrasted with the results of statistical arguments applied to a box of strings in dynamical equilibrium. We argue that if point defects were to form with smaller probability, the distance between monopoles and antimonopoles would decrease while the monopole-to-monopole distance would increase. We find that monopoles are always paired with antimonopoles but the pairing becomes clean only when the number density of defects is small. A similar reasoning would also apply to other defects

  12. Showing Value (Editorial

    Denise Koufogiannakis

    2009-06-01

    Full Text Available When Su Cleyle and I first decided to start Evidence Based Library and Information Practice, one of the things we agreed upon immediately was that the journal be open access. We knew that a major obstacle to librarians using the research literature was that they did not have access to the research literature. Although Su and I are both academic librarians who can access a wide variety of library and information literature from our institutions, we belong to a profession where not everyone has equal access to the research in our field. Without such access to our own body of literature, how can we ever hope for practitioners to use research evidence in their decision making? It would have been contradictory to the principles of evidence based library and information practice to do otherwise.One of the specific groups we thought could use such an open access venue for discovering research literature was school librarians. School librarians are often isolated and lacking access to the research literature that may help them prove to stakeholders the importance of their libraries and their role within schools. Certainly, school libraries have been in decline and the use of evidence to show value is needed. As Ken Haycock noted in his 2003 report, The Crisis in Canada’s School Libraries: The Case for Reform and Reinvestment, “Across the country, teacher-librarians are losing their jobs or being reassigned. Collections are becoming depleted owing to budget cuts. Some principals believe that in the age of the Internet and the classroom workstation, the school library is an artifact” (9. Within this context, school librarians are looking to our research literature for evidence of the impact that school library programs have on learning outcomes and student success. They are integrating that evidence into their practice, and reflecting upon what can be improved locally. They are focusing on students and showing the impact of school libraries and

  13. Fibrous metaphyseal defect (fibrous cortical defect, non-ossifying fibroma)

    Freyschmidt, J.; Saure, D.; Dammenhain, S.

    1981-01-01

    Fibrous cortical defect and nonossifying fibromas can be classified together as fibrous metaphyseal defects (FMD) since they have the same pahtological substrate, with a tendency to the same localisation around the knee, and occuring at the same age. They have a tendency to spontaneous healing, are clinically silent and are usually discovered accidentally during radiological examination. A radiological survey fo 5.674 metaphyseal regions in the upper and lower extremities of 2.065 unselected patients aged one to 20 years revealed an incidence of 1.8%; exlcusive examination of the distal femur showed an incidence of 2.7%. 96% of all lesions were in the lower extremities and only 4% in the upper. The marked discrepancy in the incidence rate between American and German publications is discussed. (orig.) [de

  14. Ventricular Septal Defect (VSD)

    ... Call your doctor if your baby or child: Tires easily when eating or playing Is not gaining ... heart procedures. Risk factors Ventricular septal defects may run in families and sometimes may occur with other ...

  15. Birth Defects: Cerebral Palsy

    ... Loss > Birth defects & other health conditions > Cerebral palsy Cerebral palsy E-mail to a friend Please fill in ... this page It's been added to your dashboard . Cerebral palsy (also called CP) is a group of conditions ...

  16. Endocardial cushion defect

    ... Philadelphia, PA: Elsevier; 2016:chap 426. Kouchoukos NT, Blackstone EH, Hanley FL, Kirklin JK. Atrioventricular septal defect. In: Kouchoukos NT, Blackstone EH, Hanley FL, Kirklin JK, eds. Kirklin/Barratt- ...

  17. Repairing Nanoparticle Surface Defects

    Marino, Emanuele; Kodger, Thomas E.; Crisp, R.W.; Timmerman, Dolf; MacArthur, Katherine E.; Heggen, Marc; Schall, Peter

    2017-01-01

    Solar devices based on semiconductor nanoparticles require the use of conductive ligands; however, replacing the native, insulating ligands with conductive metal chalcogenide complexes introduces structural defects within the crystalline nanostructure that act as traps for charge carriers. We

  18. Point defects in platinum

    Piercy, G.R.

    1960-01-01

    An investigation was made of the mobility and types of point defect introduced in platinum by deformation in liquid nitrogen, quenching into water from 1600 o C, or reactor irradiation at 50 o C. In all cases the activation energy for motion of the defect was determined from measurements of electrical resistivity. Measurements of density, hardness, and x-ray line broadening were also made there applicable. These experiments indicated that the principal defects remaining in platinum after irradiation were single vacant lattice sites and after quenching were pairs of vacant lattice sites. Those present after deformation In liquid nitrogen were single vacant lattice sites and another type of defect, perhaps interstitial atoms. (author)

  19. Defect assessment benchmark studies

    Hooton, D.G.; Sharples, J.K.

    1995-01-01

    Assessments of the resistance to fast fracture of the beltline region of a PWR vessel subjected to a pressurized thermal shock (PTS) transient have been carried out using the procedures of French (RCC-M) and German (KTA) design codes, and comparisons made with results obtained using the R6 procedure as applied for Sizewell B. The example chosen for these comparisons is of a generic nature, and is taken as the PTS identified by the Hirsch addendum to the Second Marshall report (1987) as the most severe transient with regard to vessel integrity. All assessment methods show the beltline region of the vessel to be safe from the risk of fast fracture, but by varying factors of safety. These factors are discussed in terms of margins between limiting and reference defect sizes, fracture toughness and stress intensity factor, and material temperature and temperature at the onset of upper-shelf materials behaviour. Based on these studies, consideration is given to issues involved in the harmonization of those sections of the design codes which are concerned with methods for the demonstration of the avoidance of the risk of failure by fast fracture. (author)

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

    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.)

  1. Mass defect effects in atomic clocks

    Yudin, Valeriy; Taichenachev, Alexey

    2018-03-01

    We consider some implications of the mass defect on the frequency of atomic transitions. We have found that some well-known frequency shifts (the gravitational shift and motion-induced shifts such as quadratic Doppler and micromotion shifts) can be interpreted as consequences of the mass defect in quantum atomic physics, i.e. without the need for the concept of time dilation used in special and general relativity theories. Moreover, we show that the inclusion of the mass defect leads to previously unknown shifts for clocks based on trapped ions.

  2. Study of irradiation induced defects in silicon

    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. Ab initio study of point defects in magnesium oxide

    Gilbert, C. A.; Kenny, S. D.; Smith, R.; Sanville, E.

    2007-01-01

    Energetics of a variety of point defects in MgO have been considered from an ab initio perspective using density functional theory. The considered defects are isolated Schottky and Frenkel defects and interstitial pairs, along with a number of Schottky defects and di-interstitials. Comparisons were made between the density functional theory results and results obtained from empirical potential simulations and these generally showed good agreement. Both methodologies predicted the first nearest neighbor Schottky defects to be the most energetically favorable of the considered Schottky defects and that the first, second, and fifth nearest neighbor di-interstitials were of similar energy and were favored over the other di-interstitial configurations. Relaxed structures of the defects were analyzed, which showed that empirical potential simulations were accurately predicting the displacements of atoms surrounding di-interstitials, but were overestimating O atom displacement for Schottky defects. Transition barriers were computed for the defects using the nudged elastic band method. Vacancies and Schottky defects were found to have relatively high energy barriers, the majority of which were over 2 eV, in agreement with conclusions reached using empirical potentials. The lowest barriers for di-interstitial transitions were found to be for migration into a first nearest neighbor configuration. Charges were calculated using a Bader analysis and this found negligible charge transfer during the defect transitions and only small changes in the charges on atoms surrounding defects, indicating why fixed charge models work as well as they do

  4. Curvature-Controlled Topological Defects

    Luka Mesarec

    2017-05-01

    Full Text Available Effectively, two-dimensional (2D closed films exhibiting in-plane orientational ordering (ordered shells might be instrumental for the realization of scaled crystals. In them, ordered shells are expected to play the role of atoms. Furthermore, topological defects (TDs within them would determine their valence. Namely, bonding among shells within an isotropic liquid matrix could be established via appropriate nano-binders (i.e., linkers which tend to be attached to the cores of TDs exploiting the defect core replacement mechanism. Consequently, by varying configurations of TDs one could nucleate growth of scaled crystals displaying different symmetries. For this purpose, it is of interest to develop a simple and robust mechanism via which one could control the position and number of TDs in such atoms. In this paper, we use a minimal mesoscopic model, where variational parameters are the 2D curvature tensor and the 2D orientational tensor order parameter. We demonstrate numerically the efficiency of the effective topological defect cancellation mechanism to predict positional assembling of TDs in ordered films characterized by spatially nonhomogeneous Gaussian curvature. Furthermore, we show how one could efficiently switch among qualitatively different structures by using a relative volume v of ordered shells, which represents a relatively simple naturally accessible control parameter.

  5. Electronic transport of bilayer graphene with asymmetry line defects

    Zhao Xiao-Ming; Chen Chan; Liang Ying; Kou Su-Peng; Wu Ya-Jie

    2016-01-01

    In this paper, we study the quantum properties of a bilayer graphene with (asymmetry) line defects. The localized states are found around the line defects. Thus, the line defects on one certain layer of the bilayer graphene can lead to an electric transport channel. By adding a bias potential along the direction of the line defects, we calculate the electric conductivity of bilayer graphene with line defects using the Landauer–Büttiker theory, and show that the channel affects the electric conductivity remarkably by comparing the results with those in a perfect bilayer graphene. This one-dimensional line electric channel has the potential to be applied in nanotechnology engineering. (paper)

  6. PAT challenges routine techniques on defect spectroscopy in material science

    Badawi, E.A.

    2005-01-01

    Atomic or Point Defects are the most simple defects in solids. Due to the small size their direct observation by the routine techniques is not possible. A single type of defects (thermal defect) was observed in the quenching process. Using the Arrhenius method and threshold method we recommended the accurate both method of treatments. The calculated values for formation enthalpies and self-diffusion using positron lifetime and Doppler broadening in a good agreement in (A356.0) and (A413.1). Specifically it is show how PAT detect defect concentrations, (formation- migration) enthalpies and grain size for the material under investigation. Most of the these data are reported

  7. Repairing Nanoparticle Surface Defects.

    Marino, Emanuele; Kodger, Thomas E; Crisp, Ryan W; Timmerman, Dolf; MacArthur, Katherine E; Heggen, Marc; Schall, Peter

    2017-10-23

    Solar devices based on semiconductor nanoparticles require the use of conductive ligands; however, replacing the native, insulating ligands with conductive metal chalcogenide complexes introduces structural defects within the crystalline nanostructure that act as traps for charge carriers. We utilized atomically thin semiconductor nanoplatelets as a convenient platform for studying, both microscopically and spectroscopically, the development of defects during ligand exchange with the conductive ligands Na 4 SnS 4 and (NH 4 ) 4 Sn 2 S 6 . These defects can be repaired via mild chemical or thermal routes, through the addition of L-type ligands or wet annealing, respectively. This results in a higher-quality, conductive, colloidally stable nanomaterial that may be used as the active film in optoelectronic devices. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  8. Defect identification using positrons

    Beling, C.D.; Fung, S.

    2001-01-01

    The current use of the lifetime and Doppler broadening techniques in defect identification is demonstrated with two studies, the first being the identification of carbon vacancy in n-6H SiC through lifetime spectroscopy, and the second the production of de-hydrogenated voids in α-Si:H through light soaking. Some less conventional ideas are presented for more specific defect identification, namely (i) the amalgamation of lifetime and Doppler techniques with conventional deep level transient spectroscopy in what may be called ''positron-deep level transient spectroscopy'', and (ii) the extraction of more spatial information on vacancy defects by means of what may be called ''Fourier transform Doppler broadening of annihilation radiation spectroscopy'' (orig.)

  9. Quantum computing with defects

    Varley, Joel

    2011-03-01

    The development of a quantum computer is contingent upon the identification and design of systems for use as qubits, the basic units of quantum information. One of the most promising candidates consists of a defect in diamond known as the nitrogen-vacancy (NV-1) center, since it is an individually-addressable quantum system that can be initialized, manipulated, and measured with high fidelity at room temperature. While the success of the NV-1 stems from its nature as a localized ``deep-center'' point defect, no systematic effort has been made to identify other defects that might behave in a similar way. We provide guidelines for identifying other defect centers with similar properties. We present a list of physical criteria that these centers and their hosts should meet and explain how these requirements can be used in conjunction with electronic structure theory to intelligently sort through candidate systems. To elucidate these points, we compare electronic structure calculations of the NV-1 center in diamond with those of several deep centers in 4H silicon carbide (SiC). Using hybrid functionals, we report formation energies, configuration-coordinate diagrams, and defect-level diagrams to compare and contrast the properties of these defects. We find that the NC VSi - 1 center in SiC, a structural analog of the NV-1 center in diamond, may be a suitable center with very different optical transition energies. We also discuss how the proposed criteria can be translated into guidelines to discover NV analogs in other tetrahedrally coordinated materials. This work was performed in collaboration with J. R. Weber, W. F. Koehl, B. B. Buckley, A. Janotti, C. G. Van de Walle, and D. D. Awschalom. This work was supported by ARO, AFOSR, and NSF.

  10. Defects in semiconductors

    Pimentel, C.A.F.

    1983-01-01

    Some problems openned in the study of defects in semiconductors are presented. In particular, a review is made of the more important problems in Si monocrystals of basic and technological interest: microdefects and the presence of oxigen and carbon. The techniques usually utilized in the semiconductor material characterization are emphatized according its potentialities. Some applications of x-ray techniques in the epitaxial shell characterization in heterostructures, importants in electronic optics, are shown. The increase in the efficiency of these defect analysis methods in semiconductor materials with the use of synchrotron x-ray sources is shown. (L.C.) [pt

  11. Residual Defect Density in Random Disks Deposits.

    Topic, Nikola; Pöschel, Thorsten; Gallas, Jason A C

    2015-08-03

    We investigate the residual distribution of structural defects in very tall packings of disks deposited randomly in large channels. By performing simulations involving the sedimentation of up to 50 × 10(9) particles we find all deposits to consistently show a non-zero residual density of defects obeying a characteristic power-law as a function of the channel width. This remarkable finding corrects the widespread belief that the density of defects should vanish algebraically with growing height. A non-zero residual density of defects implies a type of long-range spatial order in the packing, as opposed to only local ordering. In addition, we find deposits of particles to involve considerably less randomness than generally presumed.

  12. Entanglement entropy in integrable field theories with line defects II. Non-topological defect

    Jiang, Yunfeng

    2017-08-01

    This is the second part of two papers where we study the effect of integrable line defects on bipartite entanglement entropy in integrable field theories. In this paper, we consider non-topological line defects in Ising field theory. We derive an infinite series expression for the entanglement entropy and show that both the UV and IR limits of the bulk entanglement entropy are modified by the line defect. In the UV limit, we give an infinite series expression for the coefficient in front of the logarithmic divergence and the exact defect g-function. By tuning the defect to be purely transmissive and reflective, we recover correctly the entanglement entropy of the bulk and with integrable boundary respectively.

  13. Quantum computing with defects.

    Weber, J R; Koehl, W F; Varley, J B; Janotti, A; Buckley, B B; Van de Walle, C G; Awschalom, D D

    2010-05-11

    Identifying and designing physical systems for use as qubits, the basic units of quantum information, are critical steps in the development of a quantum computer. Among the possibilities in the solid state, a defect in diamond known as the nitrogen-vacancy (NV(-1)) center stands out for its robustness--its quantum state can be initialized, manipulated, and measured with high fidelity at room temperature. Here we describe how to systematically identify other deep center defects with similar quantum-mechanical properties. We present a list of physical criteria that these centers and their hosts should meet and explain how these requirements can be used in conjunction with electronic structure theory to intelligently sort through candidate defect systems. To illustrate these points in detail, we compare electronic structure calculations of the NV(-1) center in diamond with those of several deep centers in 4H silicon carbide (SiC). We then discuss the proposed criteria for similar defects in other tetrahedrally coordinated semiconductors.

  14. A novel inspection system for cosmetic defects

    Hazra, S.; Roy, R.; Williams, D.; Aylmore, R.; Hollingdale, D.

    2013-12-01

    The appearance of automotive skin panels creates desirability for a product and differentiates it from the competition. Because of the importance of skin panels, considerable care is taken in minimizing defects such as the 'hollow' defect that occur around door-handle depressions. However, the inspection process is manual, subjective and time-consuming. This paper describes the development of an objective and inspection scheme for the 'hollow' defect. In this inspection process, the geometry of a panel is captured using a structured lighting system. The geometry data is subsequently analyzed by a purpose-built wavelet-based algorithm to identify the location of any defects that may be present and to estimate the perceived severity of the defects without user intervention. This paper describes and critically evaluates the behavior of this physically-based algorithm on an ideal and real geometry and compares its result to an actual audit. The results show that the algorithm is capable of objectively locating and classifying 'hollow' defects in actual panels.

  15. Experimental study of defect power reactor fuel. Final report

    Forsyth, R.S.; Jonsson, T.

    1982-01-01

    Two BWR fuel rods, one intact and one defect, with the same manufacturing and irradiation data have been examined in a comparative study. The defect rod has been irradiated in a defect condition during approximately one reactor cycle and has consequently some secondary defects. The defect rod has two penetrating defects at a distance of about 1.5 meters from each other. Comparison with the intact rod shows a large Cs loss from the defect rod, especially between the cladding defects, where the loss is measured to about 30 %. The leachibility in deionized water is higher for Cs, U and Cm for fuel from the defect rod. The leaching results are more complex for Sr-90, Pu and Am. The fuel in the defect rod has undergone a change of structure with gain growth and formation of oriented fuel structure. The cladding of the defect rod is hydrided locally in some parts of the lower part of the rod and furthermore over a more extended region near the end of the rod. (Authors)

  16. Polydispersity-driven topological defects as order-restoring excitations.

    Yao, Zhenwei; Olvera de la Cruz, Monica

    2014-04-08

    The engineering of defects in crystalline matter has been extensively exploited to modify the mechanical and electrical properties of many materials. Recent experiments on manipulating extended defects in graphene, for example, show that defects direct the flow of electric charges. The fascinating possibilities offered by defects in two dimensions, known as topological defects, to control material properties provide great motivation to perform fundamental investigations to uncover their role in various systems. Previous studies mostly focus on topological defects in 2D crystals on curved surfaces. On flat geometries, topological defects can be introduced via density inhomogeneities. We investigate here topological defects due to size polydispersity on flat surfaces. Size polydispersity is usually an inevitable feature of a large variety of systems. In this work, simulations show well-organized induced topological defects around an impurity particle of a wrong size. These patterns are not found in systems of identical particles. Our work demonstrates that in polydispersed systems topological defects play the role of restoring order. The simulations show a perfect hexagonal lattice beyond a small defective region around the impurity particle. Elasticity theory has demonstrated an analogy between the elementary topological defects named disclinations to electric charges by associating a charge to a disclination, whose sign depends on the number of its nearest neighbors. Size polydispersity is shown numerically here to be an essential ingredient to understand short-range attractions between like-charge disclinations. Our study suggests that size polydispersity has a promising potential to engineer defects in various systems including nanoparticles and colloidal crystals.

  17. Congenital Heart Defects (For Parents)

    ... 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 ...

  18. Antigravity from a spacetime defect

    Klinkhamer, F. R.; Queiruga, J. M.

    2018-01-01

    We argue that there may exist spacetime defects embedded in Minkowski spacetime, which have negative active gravitational mass. One such spacetime defect then repels a test particle, corresponding to what may be called "antigravity."

  19. Studies of defects and defect agglomerates by positron annihilation spectroscopy

    Eldrup, Morten Mostgaard; Singh, B.N.

    1997-01-01

    A brief introduction to positron annihilation spectroscopy (PAS), and in particular lo its use for defect studies in metals is given. Positrons injected into a metal may become trapped in defects such as vacancies, vacancy clusters, voids, bubbles and dislocations and subsequently annihilate from...... the trapped state iri the defect. The annihilation characteristics (e.g., the lifetime of the positron) can be measured and provide information about the nature of the defect (e.g., size, density, morphology). The technique is sensitive to both defect size (in the range from monovacancies up to cavities...

  20. Congenital Heart Defects and CCHD

    ... and more. Stony Point, NY 10980 Close X Home > Complications & Loss > Birth defects & other health conditions > Congenital heart defects and ... in congenital heart defects. You have a family history of congenital heart ... syndrome or VCF. After birth Your baby may be tested for CCHD as ...

  1. Immobile defects in ferroelastic walls: Wall nucleation at defect sites

    He, X.; Salje, E. K. H.; Ding, X.; Sun, J.

    2018-02-01

    Randomly distributed, static defects are enriched in ferroelastic domain walls. The relative concentration of defects in walls, Nd, follows a power law distribution as a function of the total defect concentration C: N d ˜ C α with α = 0.4 . The enrichment Nd/C ranges from ˜50 times when C = 10 ppm to ˜3 times when C = 1000 ppm. The resulting enrichment is due to nucleation at defect sites as observed in large scale MD simulations. The dynamics of domain nucleation and switching is dependent on the defect concentration. Their energy distribution follows the power law with exponents during yield between ɛ ˜ 1.82 and 2.0 when the defect concentration increases. The power law exponent is ɛ ≈ 2.7 in the plastic regime, independent of the defect concentration.

  2. Breakdown, fractoemission, diffusion: role of defects in dielectrics

    Vigouroux, J.P.; Serruys, Y.

    1987-01-01

    During the surface analysis of dielectric materials, the impinging ionising particles induce point defects localised in the band gap and build an electrical charge. The electric field created by the charged defects modifies the physico-chemical properties of surface and bulk. We show that the fundamental study of defects allows a better understanding of technological phenomena such as dielectric breakdown, fracture and diffusion [fr

  3. The effect of dietary protein on reproduction in the mare. IV. Serum progestagen, FSH, LH and melatonin concentrations during the anovulatory, transitional and ovulatory periods in the non-pregnant mare

    F.E. Van Niekerk

    1997-07-01

    Full Text Available The effect of total protein intake and protein quality on the serum concentrations of certain reproductive hormones during the anovulatory, transitional and ovulatory periods were studied in 36 Anglo-Arab mares. High-quality protein stimulated FSH and LH production during the late transitional period. Serum progestagen and melatonin concentrations were unaffected by the quality of protein nutrition during the anovulatory period. Mares receiving high-quality protein exhibited a 10-14-day cyclical pattern of FSH release approximately 4-6 weeks earlier than the mares fed the lower-quality protein diet, and also ovulated 3-4 weeks earlier than the mares on the lower-quality protein diet. Progesterone concentrations during the 1st oestrous cycle after the anovulatory period were unaffected by protein quality in the diet.

  4. Surface defects and chiral algebras

    Córdova, Clay [School of Natural Sciences, Institute for Advanced Study,1 Einstein Dr, Princeton, NJ 08540 (United States); Gaiotto, Davide [Perimeter Institute for Theoretical Physics,31 Caroline St N, Waterloo, ON N2L 2Y5 (Canada); Shao, Shu-Heng [School of Natural Sciences, Institute for Advanced Study,1 Einstein Dr, Princeton, NJ 08540 (United States)

    2017-05-26

    We investigate superconformal surface defects in four-dimensional N=2 superconformal theories. Each such defect gives rise to a module of the associated chiral algebra and the surface defect Schur index is the character of this module. Various natural chiral algebra operations such as Drinfeld-Sokolov reduction and spectral flow can be interpreted as constructions involving four-dimensional surface defects. We compute the index of these defects in the free hypermultiplet theory and Argyres-Douglas theories, using both infrared techniques involving BPS states, as well as renormalization group flows onto Higgs branches. In each case we find perfect agreement with the predicted characters.

  5. Poor embryo development in post-ovulatory in vivo-aged mouse oocytes is associated with mitochondrial dysfunction, but mitochondrial transfer from somatic cells is not sufficient for rejuvenation.

    Igarashi, Hideki; Takahashi, Toshifumi; Abe, Hiroyuki; Nakano, Hiroshi; Nakajima, Osamu; Nagase, Satoru

    2016-10-01

    Does in vivo aging of mouse oocytes affect mitochondrial function? Mitochondrial function was impaired in post-ovulatory in vivo-aged mouse oocytes and microinjection of somatic cell mitochondria did not rescue poor fertilization and embryonic development rates. The mechanisms underlying the decline in oocyte quality associated with oocyte aging remain unknown, although studies have suggested that the decline is regulated by mitochondrial dysfunction. However, only a limited number of studies have provided direct evidence implicating mitochondrial dysfunction in oocyte quality during the aging of oocytes. We used post-ovulatory, in vivo-aged mouse oocytes as a model for studying low-quality oocytes in oocyte aging. Superovulated oocytes released from the oviduct at 14 h and 20-24 h post-hCG injection were designated as 'fresh' and 'aged' oocytes, respectively. Membrane potentials and oxygen consumption in single oocytes were evaluated as measures of mitochondrial function in fresh and aged oocytes. Mitochondrial transcriptional factor A (TFAM) expression levels were examined by western blotting, and colocalization of mitochondria and TFAM was analyzed by measuring immunofluorescence in fresh and aged oocytes. IVF and blastocyst formation rates were calculated after oocyte microinjection with mitochondria derived from liver cells. The average mitochondrial membrane potential in fresh oocytes was significantly higher than that in aged oocytes (P transfer of cytosolic factors or cellular organelles, such as the endoplasmic reticulum or mitochondria, from specific cell types. This study was supported by Grants-in-Aid for General Science Research to Toshifumi Takahashi (No. 25462550) and Hideki Igarashi (No. 26462474). The funding source played no role in study design in the collection, analysis, and interpretation of data; in the writing of the report; and in the decision to submit the article for publication. The authors have no conflict of interest to disclose.

  6. [Progress of Masquelet technique to repair bone defect].

    Yin, Qudong; Sun, Zhenzhong; Gu, Sanjun

    2013-10-01

    To summarize the progress of Masquelet technique to repair bone defect. The recent literature concerning the application of Masquelet technique to repair bone defect was extensively reviewed and summarized. Masquelet technique involves a two-step procedure. First, bone cement is used to fill the bone defect after a thorough debridement, and an induced membrane structure surrounding the spacer formed; then the bone cement is removed after 6-8 weeks, and rich cancellous bone is implanted into the induced membrane. Massive cortical bone defect is repaired by new bone forming and consolidation. Experiments show that the induced membrane has vascular system and is also rich in vascular endothelial growth factor, transforming growth factor beta1, bone morphogenetic protein 2, and bone progenitor cells, so it has osteoinductive property; satisfactory results have been achieved in clinical application of almost all parts of defects, various types of bone defect and massive defect up to 25 cm long. Compared with other repair methods, Masquelet technique has the advantages of reliable effect, easy to operate, few complications, low requirements for recipient site, and wide application. Masquelet technique is an effective method to repair bone defect and is suitable for various types of bone defect, especially for bone defects caused by infection and tumor resection.

  7. Sub-surface defect detection using transient thermography

    Mohd Zaki Umar; Huda Abdullah; Abdul Razak Hamzah; Wan Saffiey Wan Abdullah; Ibrahim Ahmad; Vavilov, Vladimir

    2009-04-01

    An experimental research had been carried out to study the potential of transient thermography in detecting sub-surface defect of non-metal material. In this research, eight pieces of bakelite material were used as samples. Each samples had a sub-surface defect in the circular shape with different diameters and depths. Experiment was conducted using one-sided Pulsed Thermal technique. Heating of samples were done using 30 k Watt adjustable quartz lamp while infra red (IR) images of samples were recorded using THV 550 IR camera. These IR images were then analysed with thermo fit TM Pro software to obtain the Maximum Absolute Differential Temperature Signal value, ΔT max and the time of its appearance, τ max (ΔT). Result showed that all defects were able to be detected even for the smallest and deepest defect (diameter = 5 mm and depth = 4 mm). However the highest value of Differential Temperature Signal (ΔT max ), were obtained at defect with the largest diameter, 20 mm and at the shallowest depth, 1 mm. As a conclusion, the sensitivity of the pulsed thermography technique to detect sub-surface defects of bakelite material is proportionately related with the size of defect diameter if the defect area at the same depth. On the contrary, the sensitivity of the pulsed thermography technique inversely related with the depth of defect if the defects have similar diameter size. (author)

  8. Observation of defects evolution in electronic materials

    Jang, Jung Hun

    Advanced characterization techniques have been used to obtain a better understanding of the microstructure of electronic materials. The structural evolution, especially defects, has been investigated during the film growth and post-growth processes. Obtaining the relation between the defect evolution and growth/post-growth parameters is very important to obtain highly crystalline films. In this work, the growth and post-growth related defects in GaN, ZnO, strained-Si/SiGe films have been studied using several advanced characterization techniques. First of all, the growth of related defects in GaN and p-type ZnO films have been studied. The effect of growth parameters, such as growth temperature, gas flow rate, dopants used during the deposition, on the crystalline quality of the GaN and ZnO layers was investigated by high resolution X-ray diffraction (HRXRD) and transmission electron microscopy (TEM). In GaN films, it was found that the edge and mixed type threading dislocations were the dominant defects so that the only relevant figure of merit (FOM) for the crystalline quality should be the FWHM value of o-RC of the surface perpendicular plane which could be determined by a grazing incidence x-ray diffraction (GIXD) technique as shown in this work. The understanding of the relationship between the defect evolution and growth parameters allowed for the growth of high crystalline GaN films. For ZnO films, it was found that the degree of texture and crystalline quality of P-doped ZnO films decreased with increasing the phosphorus atomic percent. In addition, the result from the x-ray diffraction line profile analysis showed that the 0.5 at % P-doped ZnO film showed much higher microstrain than the 1.0 at % P-doped ZnO film, which indicated that the phosphorus atoms were segregated with increasing P atomic percentage. Finally, post-growth related defects in strained-Si/SiGe films were investigated. Postgrowth processes used in this work included high temperature N2

  9. Point defects in nickel

    Peretto, P.

    1969-01-01

    The defects in electron irradiated nickel (20 deg. K) or neutron irradiated nickel (28 deg. K) are studied by simultaneous analysis using the magnetic after-effect, electron microscopy and electrical resistivity recovery. We use zone refined nickel (99.999 per cent) which, for some experiments, is alloyed with a small amount of iron (for example 0.1 per cent Fe). The temperature dependant electrical recovery may be divided in four stages. The sub-stages I B (31 deg. K), I C (42 deg. K), I D (from to 57 deg. K) and I E (62 deg. K) of stage I are due to the disappearance of single interstitials into vacancies. The interstitial defect has a split configuration with a migration energy of about 0.15 eV. In the close pair which disappears in stage I B the interstitial is found to be in a 3. neighbour position whilst in stage I D it is near the direction from the vacancy. In stage I E there is no longer any interaction between the interstitial and the vacancy. The stage II is due to more complicated interstitial defects: di-interstitials for stage II B (84 deg. K) and larger and larger interstitial loops for the following sub-stages. The loops may be seen by electron microscopy. Impurities can play the role of nucleation centers for the loops. Stages III A (370 deg. K) and III B (376 deg. K) are due to two types of di-vacancies. During stage IV (410 deg. K) the single vacancies migrate. Vacancy type loops and interstitial type loops grow concurrently and disappear at about 800 deg. K as observed by electron microscopy. (author) [fr

  10. Single ventricle cardiac defect

    Eren, B.; Turkmen, N.; Fedakar, R.; Cetin, V.

    2010-01-01

    Single ventricle heart is defined as a rare cardiac abnormality with a single ventricle chamber involving diverse functional and physiological defects. Our case is of a ten month-old baby boy who died shortly after admission to the hospital due to vomiting and diarrhoea. Autopsy findings revealed cyanosis of finger nails and ears. Internal examination revealed; large heart, weighing 60 grams, single ventricle, without a septum and upper membranous part. Single ventricle is a rare pathology, hence, this paper aims to discuss this case from a medico-legal point of view. (author)

  11. Eddy current inspection of weld defects in tubing

    Katragadda, G.; Lord, W.

    1992-01-01

    An approach using differential probes for the inspection of weld defects in tubing is studied. Finite element analysis is used to model the weld regions and defects. Impedance plane signals are predicted for different weld defect types and compared wherever possible with signals from actual welds in tubing. Results show that detection and sizing of defects in tubing is possible using differential eddy current techniques. The phase angle of the impedance plane trajectory gives a good indication of the sizing of the crack. Data on the type of defect can be obtained from the shape of the impedance plane trajectory and the phase. Depending on the skin depth, detection of outer wall, inner wall, and subsurface defects is possible.

  12. A defect-driven diagnostic method for machine tool spindles.

    Vogl, Gregory W; Donmez, M Alkan

    2015-01-01

    Simple vibration-based metrics are, in many cases, insufficient to diagnose machine tool spindle condition. These metrics couple defect-based motion with spindle dynamics; diagnostics should be defect-driven. A new method and spindle condition estimation device (SCED) were developed to acquire data and to separate system dynamics from defect geometry. Based on this method, a spindle condition metric relying only on defect geometry is proposed. Application of the SCED on various milling and turning spindles shows that the new approach is robust for diagnosing the machine tool spindle condition.

  13. Electron transport in ethanol & methanol absorbed defected graphene

    Dandeliya, Sushmita; Srivastava, Anurag

    2018-05-01

    In the present paper, the sensitivity of ethanol and methanol molecules on surface of single vacancy defected graphene has been investigated using density functional theory (DFT). The changes in structural and electronic properties before and after adsorption of ethanol and methanol were analyzed and the obtained results show high adsorption energy and charge transfer. High adsorption happens at the active site with monovacancy defect on graphene surface. Present work confirms that the defected graphene increases the surface reactivity towards ethanol and methanol molecules. The presence of molecules near the active site affects the electronic and transport properties of defected graphene which makes it a promising choice for designing methanol and ethanol sensor.

  14. Anosognosia for obvious visual field defects in stroke patients.

    Baier, Bernhard; Geber, Christian; Müller-Forell, Wiebke; Müller, Notger; Dieterich, Marianne; Karnath, Hans-Otto

    2015-01-01

    Patients with anosognosia for visual field defect (AVFD) fail to recognize consciously their visual field defect. There is still unclarity whether specific neural correlates are associated with AVFD. We studied AVFD in 54 patients with acute stroke and a visual field defect. Nineteen percent of this unselected sample showed AVFD. By using modern voxelwise lesion-behaviour mapping techniques we found an association between AVFD and parts of the lingual gyrus, the cuneus as well as the posterior cingulate and corpus callosum. Damage to these regions appears to induce unawareness of visual field defects and thus may play a significant role for conscious visual perception.

  15. CT appearance of congenital defect resembling the Hangman's fracture

    Williams, J.P. III; Baker, D.H.; Miller, W.A.

    1999-01-01

    Purpose. Congenital defects of C2 are rare and can be confused with Hangman's fractures. CT has been advocated as aiding in differentiation between an acute fracture and congenital defects. Methods. We present a case of a 2-year-old recent accident victim, who was erroneously diagnosed by plain film and CT as having a Hangman's fracture. Results. The CT demonstrated an atypical appearance of a congenital defect. Conclusion. This case shows that the radiographic differentiation between a Hangman's fracture and a congenital defect is more difficult than previously described. (orig.)

  16. Dipole defects in beryl

    Holanda, B A; Cordeiro, R C; Blak, A R

    2010-01-01

    Dipole defects in gamma irradiated and thermally treated beryl (Be 3 Al 2 Si 6 O 18 ) samples have been studied using the Thermally Stimulated Depolarization Currents (TSDC) technique. TSDC experiments were performed in pink (morganite), green (emerald), blue (aquamarine) and colourless (goshenite) natural beryl. TSDC spectra present dipole peaks at 190K, 220K, 280K and 310K that change after gamma irradiation and thermal treatments. In morganite samples, for thermal treatments between 700K and 1100K, the 280K peak increase in intensity and the band at 220K disappears. An increase of the 280K peak and a decrease of the 190K peak were observed in the TSDC spectra of morganite after a gamma irradiation of 25kGy performed after the thermal treatments. In the case of emerald samples, thermal treatments enhanced the 280K peak and gamma irradiation partially destroyed this band. The goshenite TSDC spectra present only one band at 280K that is not affected either by thermal treatments or by gamma irradiation. All the observed peaks are of dipolar origin because the intensity of the bands is linearly dependent on the polarization field, behaviour of dipole defects. The systematic study, by means of TSDC measurements, of ionizing irradiation effects and thermal treatments in these crystals makes possible a better understanding of the role played by the impurities in beryl crystals.

  17. Dental enamel defects in children with coeliac disease

    Werink, Claar D.; van Diermen, Denise E.; Aartman, Irene H. A.; Heymans, Hugo S. A.

    2007-01-01

    OBJECTIVE: The aim of this study was to investigate whether Dutch children with proven coeliac disease show specific dental enamel defects, and to asses whether children with the same gastrointestinal complaints, but proved no-coeliac disease, lack these specific dental enamel defects. MATERIALS AND

  18. 49 CFR 215.115 - Defective roller bearing.

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Defective roller bearing. 215.115 Section 215.115... § 215.115 Defective roller bearing. (a) A railroad may not place or continue in service a car, if the car has— (1) A roller bearing that shows signs of having been overheated as evidenced by— (i...

  19. Inflaton fluctuations in the presence of cosmological defects

    Cho, Hing-Tong; Ng, Kin-Wang; Wang, I.-Chin

    2014-11-01

    We study quantum fluctuations of a free massless scalar field during inflation in the presence of a point, line, or plane defect such as a black hole, cosmic string, or domain wall, using a perturbative expansion in powers of small defect parameters. We provide results for the scalar two-point correlation functions that show explicitly a small violation of translational invariance during inflation.

  20. Computer simulation of defect cluster

    Kuramoto, Eiichi [Kyushu Univ., Kasuga, Fukuoka (Japan). Research Inst. for Applied Mechanics

    1996-04-01

    In order to elucidate individual element process of various defects and defect clusters of used materials under irradiation environments, interatomic potential with reliability was investigated. And for comparison with experimental results, it is often required to adopt the temperature effect and to investigate in details mechanism of one dimensional motion of micro conversion loop and so forth using the molecular dynamic (MD) method. Furthermore, temperature effect is also supposed for stable structure of defects and defect clusters, and many problems relating to alloy element are also remained. And, simulation on photon life at the defects and defect clusters thought to be important under comparison with equipment can also be supposed an improvement of effectiveness due to relation to theses products. In this paper, some topics in such flow was extracted to explain them. In particular, future important problems will be potential preparation of alloy, structure, dynamic behavior and limited temperature of intralattice atomic cluster. (G.K.)

  1. Topological defects in extended inflation

    Copeland, E.J.; Kolb, E.W.; Chicago Univ., IL; Liddle, A.R.

    1990-04-01

    We consider the production of topological defects, especially cosmic strings, in extended inflation models. In extended inflation, the Universe passes through a first-order phase transition via bubble percolation, which naturally allows defects to form at the end of inflation. The correlation length, which determines the number density of the defects, is related to the mean size of bubbles when they collide. This mechanism allows a natural combination of inflation and large-scale structure via cosmic strings. 18 refs

  2. Defects in new protective aprons

    Glaze, S.; LeBlanc, A.D.; Bushong, S.C.

    1984-01-01

    Upon careful examination, several defects have been detected in new protective aprons. The nature of the defects is identified and described. Although the occurrence of such defects has not exceeded 5%, they are significant enough to warrant return of the lead apron to the supplier. It is recommended that the integrity of all new protective aprons be verified upon receipt as well as at yearly intervals

  3. Topological defects in extended inflation

    Copeland, E.J.; Kolb, E.W.; Liddle, A.R.

    1990-01-01

    We consider the production of topological defects, especially cosmic strings, in extended-inflation models. In extended inflation, the Universe passes through a first-order phase transition via bubble percolation, which naturally allows defects to form at the end of inflation. The correlation length, which determines the number density of the defects, is related to the mean size of the bubbles when they collide. This mechanism allows a natural combination of inflation and large-scale structure via cosmic strings

  4. Metastable gravity on classical defects

    Ringeval, Christophe; Rombouts, Jan-Willem

    2005-01-01

    We discuss the realization of metastable gravity on classical defects in infinite-volume extra dimensions. In dilatonic Einstein gravity, it is found that the existence of metastable gravity on the defect core requires violation of the dominant energy condition for codimension N c =2 defects. This is illustrated with a detailed analysis of a six-dimensional hyperstring minimally coupled to dilaton gravity. We present the general conditions under which a codimension N c >2 defect admits metastable modes, and find that they differ from lower codimensional models in that, under certain conditions, they do not require violation of energy conditions to support quasilocalized gravity

  5. Defect Characterization of Pyroelectric Materials

    Keeble, David

    2002-01-01

    Two methods for identify point defects applicable to the study of technologically relevant pyroelectric oxide materials have been investigated, namely Positron Annihilation Lifetime Spectroscopy (PALS...

  6. Who named the quantum defect?

    Rau, A.R.P.; Inokuti, M.

    1997-01-01

    The notion of the quantum defect is important in atomic and molecular spectroscopy and also in unifying spectroscopy with collision theory. In the latter context, the quantum defect may be viewed as an ancestor of the phase shift. However, the origin of the term quantum defect does not seem to be explained in standard textbooks. It occurred in a 1921 paper by Schroedinger, preceding quantum mechanics, yet giving the correct meaning as an index of the short-range interactions with the core of an atom. The authors present the early history of the quantum-defect idea, and sketch its recent developments

  7. Fibrous metaphyseal defects

    Hajek, P.C.; Ritschi, P.; Kramer, J.; Imhof, H.; Karnel, F.

    1988-01-01

    Eighty-two patients (107 fibrous metaphyseal defects [FMDs]) were investigated with standard radiography and MR imaging (N = 15). Twenty-two of these were followed up sequentially up to 10 years (mean, 7.3 years). Histologic studies proved that FMDs originate at the site of insertion of a tendon in the perichondrium of the epiphyseal cartilage. After normal bone growth is regained, all FMDs were found to move diaphysically, following a straight line parallel to the long axis of the FMDs. This line pointed to the insertion of the tendon originally involved, a fact that was proved with MR imaging. Four characteristic stages were found to define a typical radiomorphologic course of an FMD

  8. Cariogenic properties of Streptococcus mutans clinical isolates with sortase defects.

    Lapirattanakul, Jinthana; Takashima, Yukiko; Tantivitayakul, Pornpen; Maudcheingka, Thaniya; Leelataweewud, Pattarawadee; Nakano, Kazuhiko; Matsumoto-Nakano, Michiyo

    2017-09-01

    In Streptococcus mutans, a Gram-positive pathogen of dental caries, several surface proteins are anchored by the activity of sortase enzyme. Although various reports have shown that constructed S. mutans mutants deficient of sortase as well as laboratory reference strains with a sortase gene mutation have low cariogenic potential, no known studies have investigated clinical isolates with sortase defects. Here, we examined the cariogenic properties of S. mutans clinical isolates with sortase defects as well as caries status in humans harboring such defective isolates. Sortase-defective clinical isolates were evaluated for biofilm formation, sucrose-dependent adhesion, stress-induced dextran-dependent aggregation, acid production, and acid tolerance. Additionally, caries indices of subjects possessing such defective isolates were determined. Our in vitro results indicated that biofilm with a lower quantity was formed by sortase-defective as compared to non-defective isolates. Moreover, impairments of sucrose-dependent adhesion and stress-induced dextran-dependent aggregation were found among the isolates with defects, whereas no alterations were seen in regard to acid production or tolerance. Furthermore, glucan-binding protein C, a surface protein anchored by sortase activity, was predominantly detected in culture supernatants of all sortase-defective S. mutans isolates. Although the sortase-defective isolates showed lower cariogenic potential because of a reduction in some cariogenic properties, deft/DMFT indices revealed that all subjects harboring those isolates had caries experience. Our findings suggest the impairment of cariogenic properties in S. mutans clinical isolates with sortase defects, though the detection of these defective isolates seemed not to imply low caries risk in the subjects harboring them. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Inspection of surface defects for cladding tube with laser

    Senoo, Shigeo; Igarashi, Miyuki; Satoh, Masakazu; Miura, Makoto

    1978-01-01

    This paper presents the results of experiment on mechanizing the visual inspection of surface defects of cladding tubes and improving the reliability of surface defect inspection. Laser spot inspection method was adopted for this purpose. Since laser speckle pattern includes many informations about surface aspects, the method can be utilized as an effective means for detection or classification of the surface defects. Laser beam is focussed on cladding tube surfaces, and the reflected laser beam forms typical stellar speckle patterns on a screen. Sample cladding tubes are driven in longitudinal direction, and a photo-detector is placed at a position where secondary reflection will fall on the detector. Reflected laser beam from defect-free surfaces shows uniform distribution on the detector. When the incident focussed laser beam is directed to defects, the intensity of the reflected light is reduced. In the second method, laser beam is scanned by a rotating cube mirror. As the results of experiment, the typical patterns caused by defects were observed. It is clear that reflection patterns change with the kinds of defects. The sensitivity of defect detection decreases with the increase in laser beam diameter. Surface defect detection by intensity change was also tested. (Kato, T.)

  10. Defect tolerance in resistor-logic demultiplexers for nanoelectronics.

    Kuekes, Philip J; Robinett, Warren; Williams, R Stanley

    2006-05-28

    Since defect rates are expected to be high in nanocircuitry, we analyse the performance of resistor-based demultiplexers in the presence of defects. The defects observed to occur in fabricated nanoscale crossbars are stuck-open, stuck-closed, stuck-short, broken-wire, and adjacent-wire-short defects. We analyse the distribution of voltages on the nanowire output lines of a resistor-logic demultiplexer, based on an arbitrary constant-weight code, when defects occur. These analyses show that resistor-logic demultiplexers can tolerate small numbers of stuck-closed, stuck-open, and broken-wire defects on individual nanowires, at the cost of some degradation in the circuit's worst-case voltage margin. For stuck-short and adjacent-wire-short defects, and for nanowires with too many defects of the other types, the demultiplexer can still achieve error-free performance, but with a smaller set of output lines. This design thus has two layers of defect tolerance: the coding layer improves the yield of usable output lines, and an avoidance layer guarantees that error-free performance is achieved.

  11. Strip defect recognition in electrical tests of silicon microstrip sensors

    Valentan, Manfred, E-mail: valentan@mpp.mpg.de

    2017-02-11

    This contribution describes the measurement procedure and data analysis of AC-coupled double-sided silicon microstrip sensors with polysilicon resistor biasing. The most thorough test of a strip sensor is an electrical measurement of all strips of the sensor; the measured observables include e.g. the strip's current and the coupling capacitance. These measurements are performed to find defective strips, e.g. broken capacitors (pinholes) or implant shorts between two adjacent strips. When a strip has a defect, its observables will show a deviation from the “typical value”. To recognize and quantify certain defects, it is necessary to determine these typical values, i.e. the values the observables would have without the defect. As a novel approach, local least-median-of-squares linear fits are applied to determine these “would-be” values of the observables. A least-median-of-squares fit is robust against outliers, i.e. it ignores the observable values of defective strips. Knowing the typical values allows to recognize, distinguish and quantify a whole range of strip defects. This contribution explains how the various defects appear in the data and in which order the defects can be recognized. The method has been used to find strip defects on 30 double-sided trapezoidal microstrip sensors for the Belle II Silicon Vertex Detector, which have been measured at the Institute of High Energy Physics, Vienna (Austria).

  12. Coherent defects in superconducting circuits

    Mueller, Clemens

    2011-01-01

    The interaction of superconducting circuits with additional quantum systems is a topic that has found extensive study in the recent past. In the limit where the added system are incoherent, this is the standard field of decoherence and the system dynamics can be described by a simple master equation. In the other limit however, when the additional parts are coherent, the resulting time-evolution can become more complicated. In this thesis we have investigated the interaction of superconducting circuits with coherent and incoherent two-level defects. We have shown theoretical calculations characterizing this interaction for all relevant parameter regimes. In the weak coupling limit, the interaction can be described in an effective bath picture, where the TLS act as parts of a large, decohering environment. For strong coupling, however, the coherent dynamics of the full coupled system has to be considered. We show the calculations of the coupled time-evolution and again characterize the interaction by an effective decoherence rate. We also used experimental data to characterize the microscopic origin of the defects and the details of their interaction with the circuits. The results obtained by analyzing spectroscopic data allow us to place strong constraint on several microscopic models for the observed TLS. However, these calculations are not yet fully conclusive as to the physical nature of the TLS. We propose additional experiments to fully characterize the interaction part of the Hamiltonian, thus providing the answer to the question of the physical origin of the coupling. Additionally we have developed a method to directly drive individual defect states via virtual excitation of the qubit. This method allows one to directly probe the properties of single TLS and possibly make use of their superior coherence times for quantum information purposes. The last part of this thesis provided a way for a possible implementation of geometric quantum computation in

  13. Varying stiffness and load distributions in defective ball bearings: Analytical formulation and application to defect size estimation

    Petersen, Dick; Howard, Carl; Prime, Zebb

    2015-02-01

    This paper presents an analytical formulation of the load distribution and varying effective stiffness of a ball bearing assembly with a raceway defect of varying size, subjected to static loading in the radial, axial and rotational degrees of freedom. The analytical formulation is used to study the effect of the size of the defect on the load distribution and varying stiffness of the bearing assembly. The study considers a square-shaped outer raceway defect centered in the load zone and the bearing is loaded in the radial and axial directions while the moment loads are zero. Analysis of the load distributions shows that as the defect size increases, defect-free raceway sections are subjected to increased static loading when one or more balls completely or partly destress when positioned in the defect zone. The stiffness variations that occur when balls pass through the defect zone are significantly larger and change more rapidly at the defect entrance and exit than the stiffness variations that occur for the defect-free bearing case. These larger, more rapid stiffness variations generate parametric excitations which produce the low frequency defect entrance and exit events typically observed in the vibration response of a bearing with a square-shaped raceway defect. Analysis of the stiffness variations further shows that as the defect size increases, the mean radial stiffness decreases in the loaded radial and axial directions and increases in the unloaded radial direction. The effects of such stiffness changes on the low frequency entrance and exit events in the vibration response are simulated with a multi-body nonlinear dynamic model. Previous work used the time difference between the low frequency entrance event and the high frequency exit event to estimate the size of the defect. However, these previous defect size estimation techniques cannot distinguish between defects that differ in size by an integer number of the ball angular spacing, and a third feature

  14. Mice lacking desmocollin 1 show epidermal fragility accompanied by barrier defects and abnormal differentiation

    Chidgey, M; Brakebusch, C; Gustafsson, E

    2001-01-01

    epidermis because environmental insults are more stringent and wound healing is less rapid than in neonatal mice. This dermatitis is accompanied by localized hair loss associated with formation of utriculi and dermal cysts, denoting hair follicle degeneration. Possible resemblance of the lesions to human...

  15. Bone compositional study during healing of subcritical calvarial defects in rats by Raman spectroscopy

    Ahmed, Rafay; Wing Lun Law, Alan; Cheung, Tsz Wing; Lau, Condon

    2017-07-01

    Subcritical calvarial defects are important to study bone regeneration during healing. In this study 1mm calvarial defects were created using trephine in the parietal bones of Sprague-Dawley rats (n=7) that served as in vivo defects. Subjects were sacrificed after 7 days and the additional defects were created on the harvested skull with the same method to serve as control defects. Raman spectroscopy is established to investigate mineral/matrix ratio, carbonate/phosphate ratio and crystallinity of three different surfaces; in vivo defects, control defects and normal surface. Results show 21% and 23% decrease in mineral/matrix after 7 days of healing from surface to in vivo and control to in vivo defects, respectively. Carbonate to phosphate ratio was found to be increased by 39% while crystallinity decreased by 26% in both surface to in vivo and control to in vivo defects. This model allows to study the regenerated bone without mechanically perturbing healing surface.

  16. Thermal buckling behavior of defective CNTs under pre-load: A molecular dynamics study.

    Mehralian, Fahimeh; Tadi Beni, Yaghoub; Kiani, Yaser

    2017-05-01

    Current study is concentrated on the extraordinary properties of defective carbon nanotubes (CNTs). The role of vacancy defects in thermal buckling response of precompressed CNTs is explored via molecular dynamics (MD) simulations. Defective CNTs are initially compressed at a certain ratio of their critical buckling strain and then undergo a uniform temperature rise. Comprehensive study is implemented on both armchair and zigzag CNTs with different vacancy defects including monovacancy, symmetric bivacancy and asymmetric bivacancy. The results reveal that defects have a pronounced impact on the buckling behavior of CNTs; interestingly, defective CNTs under compressive pre-load show higher resistance to thermal buckling than pristine ones. In the following, the buckling response of defective CNTs is shown to be dependent on the vacancy defects, location of defects and chirality. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Study on on-machine defects measuring system on high power laser optical elements

    Luo, Chi; Shi, Feng; Lin, Zhifan; Zhang, Tong; Wang, Guilin

    2017-10-01

    The influence of surface defects on high power laser optical elements will cause some harm to the performances of imaging system, including the energy consumption and the damage of film layer. To further increase surface defects on high power laser optical element, on-machine defects measuring system was investigated. Firstly, the selection and design are completed by the working condition analysis of the on-machine defects detection system. By designing on processing algorithms to realize the classification recognition and evaluation of surface defects. The calibration experiment of the scratch was done by using the self-made standard alignment plate. Finally, the detection and evaluation of surface defects of large diameter semi-cylindrical silicon mirror are realized. The calibration results show that the size deviation is less than 4% that meet the precision requirement of the detection of the defects. Through the detection of images the on-machine defects detection system can realize the accurate identification of surface defects.

  18. Electronic structure of defects in semiconductor heterojunctions

    Haussy, Bernard; Ganghoffer, Jean Francois

    2002-01-01

    Full text.heterojunctions and semiconductors and superlattices are well known and well used by people interested in optoelectronics communications. Components based on the use of heterojunctions are interesting for confinement of light and increase of quantum efficiency. An heterojunction is the contact zone between two different semiconductors, for example GaAs and Ga 1-x Al x As. Superlattices are a succession of heterojunctions (up to 10 or 20). These systems have been the subjects of many experiments ao analyse the contact between semiconductors. They also have been theoretically studied by different types of approach. The main result of those studies is the prediciton of band discontinuities. Defects in heterojunctions are real traps for charge carriers; they can affect the efficiency of the component decreasing the currents and the fluxes in it. the knowledge of their electronic structure is important, a great density of defects deeply modifies the electronic structure of the whole material creating real new bands of energy in the band structure of the component. in the first part of this work, we will describe the heterostructure and the defect in terms of quantum wells and discrete levels. This approach allows us to show the role of the width of the quantum well describing the structure but induces specific behaviours due to the one dimensional modelling. Then a perturbative treatment is proposed using the Green's functions formalism. We build atomic chains with different types of atoms featuring the heterostructure and the defect. Densities of states of a structure with a defect and levels associated to the defect are obtained. Results are comparable with the free electrons work, but the modelling do not induce problems due to a one dimensional approach. To extend our modelling, a three dimensions approach, based on a cavity model, is investigated. The influence of the defect, - of hydrogenoid type - introduced in the structure, is described by a cavity

  19. Interproximal periodontal defect model in dogs: a pilot study.

    Jung, U-W; Chang, Y-Y; Um, Y-J; Kim, C-S; Cho, K-S; Choi, S-H

    2011-01-01

    This study aimed to evaluate the validity of a surgically created interproximal periodontal defect in dogs. Surgery was performed in the interproximal area between the maxillary second and third premolars in two beagle dogs. Following an incision and reflection of the gingival flap, a 3-mm wide and 5-mm high defect was prepared surgically at the interproximal area. A thorough root planing was performed and the flap was coronally positioned and sutured. The contra-lateral area was served as the control with no surgical intervention. After 8 weeks of healing, the animals were killed and the defect was analysed histometrically and radiographically. The interproximal periodontal defect resembled a naturally occurring defect and mimicked a clinical situation. After healing, the defect showed limited bone (0.89±0.02mm) and cementum regeneration (1.50± 0.48mm). Within the limitations of this pilot study, the interproximal periodontal defect showed limited bone and cementum regeneration. Thus, it can be considered as a standardized, reproducible defect model for testing new biomaterials. © 2010 John Wiley & Sons A/S.

  20. Lumber defect detection by ultrasonics

    K. A. McDonald

    1978-01-01

    Ultrasonics, the technology of high-frequency sound, has been developed as a viable means for locating most defects In lumber for use in digital form in decision-making computers. Ultrasonics has the potential for locating surface and internal defects in lumber of all species, green or dry, and rough sawn or surfaced.

  1. Neutron diffraction and lattice defects

    Hamaguchi, Yoshikazu

    1974-01-01

    Study on lattice defects by neutron diffraction technique is described. Wave length of neutron wave is longer than that of X-ray, and absorption cross-section is small. Number of defects observed by ESR is up to several defects, and the number studied with electron microscopes is more than 100. Information obtained by neutron diffraction concerns the number of defects between these two ranges. For practical analysis, several probable models are selected from the data of ESR or electron microscopes, and most probable one is determined by calculation. Then, defect concentration is obtained from scattering cross section. It is possible to measure elastic scattering exclusively by neutron diffraction. Minimum detectable concentration estimated is about 0.5% and 10 20 - 10 21 defects per unit volume. A chopper and a time of flight system are used as a measuring system. Cold neutrons are obtained from the neutron sources inserted into reactors. Examples of measurements by using similar equipments to PTNS-I system of Japan Atomic Energy Research Institute are presented. Interstitial concentration in the graphite irradiated by fast neutrons is shown. Defects in irradiated MgO were also investigated by measuring scattering cross section. Study of defects in Ge was made by measuring total cross section, and model analysis was performed in comparison with various models. (Kato, T.)

  2. Lectures on cosmic topological defects

    Vachaspati, T [Department of Astronomy and Astrophysics, Colaba, Mumbai (India) and Physics Department, Case Western Reserve University, Cleveland (United States)

    2001-11-15

    These lectures review certain topological defects and aspects of their cosmology. Unconventional material includes brief descriptions of electroweak defects, the structure of domain walls in non-Abelian theories, and the spectrum of magnetic monopoles in SU(5) Grand Unified theory. (author)

  3. Toward Intelligent Software Defect Detection

    Benson, Markland J.

    2011-01-01

    Source code level software defect detection has gone from state of the art to a software engineering best practice. Automated code analysis tools streamline many of the aspects of formal code inspections but have the drawback of being difficult to construct and either prone to false positives or severely limited in the set of defects that can be detected. Machine learning technology provides the promise of learning software defects by example, easing construction of detectors and broadening the range of defects that can be found. Pinpointing software defects with the same level of granularity as prominent source code analysis tools distinguishes this research from past efforts, which focused on analyzing software engineering metrics data with granularity limited to that of a particular function rather than a line of code.

  4. Holographic Chern-Simons defects

    Fujita, Mitsutoshi; Melby-Thompson, Charles M.; Meyer, René; Sugimoto, Shigeki

    2016-01-01

    We study SU(N) Yang-Mills-Chern-Simons theory in the presence of defects that shift the Chern-Simons level from a holographic point of view by embedding the system in string theory. The model is a D3-D7 system in Type IIB string theory, whose gravity dual is given by the AdS soliton background with probe D7 branes attaching to the AdS boundary along the defects. We holographically renormalize the free energy of the defect system with sources, from which we obtain the correlation functions for certain operators naturally associated to these defects. We find interesting phase transitions when the separation of the defects as well as the temperature are varied. We also discuss some implications for the Fractional Quantum Hall Effect and for 2-dimensional QCD.

  5. Defect forces, defect couples and path integrals in fracture mechanics

    Roche, R.L.

    1979-07-01

    In this work, it is shown that the path integrals can be introduced without any reference to the material behavior. The method is based on the definition in a continuous medium of a set of vectors and couples having the dimension of a force or a moment. More precisely, definitions are given of volume defect forces, surface defect forces, volume defect couples, and surface defect couples. This is done with the help of the stress working variation of a particule moving through the solid. The most important result is: the resultant of all the defect forces included in a volume V is the J integral on the surface surrounding V and the moment resultant is the L integral. So these integrals are defined without any assumption on the material constitutive equation. Another result is the material form of the virtual work principle - defect forces are acting like conventional forces in the conventional principles of virtual work. This lead to the introduction of the energy momentum tensor and of the associated couple stress. Application of this method is made to fracture mechanics in studying the defect forces distribution around a crack [fr

  6. Blood flow patterns underlie developmental heart defects.

    Midgett, Madeline; Thornburg, Kent; Rugonyi, Sandra

    2017-03-01

    Although cardiac malformations at birth are typically associated with genetic anomalies, blood flow dynamics also play a crucial role in heart formation. However, the relationship between blood flow patterns in the early embryo and later cardiovascular malformation has not been determined. We used the chicken embryo model to quantify the extent to which anomalous blood flow patterns predict cardiac defects that resemble those in humans and found that restricting either the inflow to the heart or the outflow led to reproducible abnormalities with a dose-response type relationship between blood flow stimuli and the expression of cardiac phenotypes. Constricting the outflow tract by 10-35% led predominantly to ventricular septal defects, whereas constricting by 35-60% most often led to double outlet right ventricle. Ligation of the vitelline vein caused mostly pharyngeal arch artery malformations. We show that both cardiac inflow reduction and graded outflow constriction strongly influence the development of specific and persistent abnormal cardiac structure and function. Moreover, the hemodynamic-associated cardiac defects recapitulate those caused by genetic disorders. Thus our data demonstrate the importance of investigating embryonic blood flow conditions to understand the root causes of congenital heart disease as a prerequisite to future prevention and treatment. NEW & NOTEWORTHY Congenital heart defects result from genetic anomalies, teratogen exposure, and altered blood flow during embryonic development. We show here a novel "dose-response" type relationship between the level of blood flow alteration and manifestation of specific cardiac phenotypes. We speculate that abnormal blood flow may frequently underlie congenital heart defects. Copyright © 2017 the American Physiological Society.

  7. Dislocation defect interaction in irradiated Cu

    Schaeublin, R.; Yao, Z.; Spaetig, P.; Victoria, M.

    2005-01-01

    Pure Cu single crystals irradiated at room temperature to low doses with 590 MeV protons have been deformed in situ in a transmission electron microscope in order to identify the basic mechanisms at the origin of hardening. Cu irradiated to 10 -4 dpa shows at room temperature a yield shear stress of 13.7 MPa to be compared to the 8.8 MPa of the unirradiated Cu. Irradiation induced damage consists at 90% of 2 nm stacking fault tetrahedra, the remaining being dislocation loops and unidentified defects. In-situ deformation reveals that dislocation-defect interaction can take several forms. Usually, dislocations pinned by defects bow out under the applied stress and escape without leaving any visible defect. From the escape angles obtained at 183 K, an average critical stress of 100 MPa is deduced. In some cases, the pinning of dislocations leads to debris that are about 20 nm long, which formation could be recorded during the in situ experiment

  8. Reality check on girth weld defect acceptance criteria

    Brust, Bud; Kalyanam, Suresh; Shim, Do-Jun; Wilkowski, Gery [Engineering Mechanics Corporation of Columbus, Columbus, OH, (United States)

    2010-07-01

    Girth weld defect tolerance criteria for pipeline construction has evolved with time. Recently, ERPG recommended a new Tier 2 girth weld defect acceptance criterion. This paper described the new development on girth weld defect acceptance criteria. The inherent conservatisms of alternative girth weld defect acceptance criteria from the 2007 API 1104 Appendix A, CSA Z662 Appendix K, are compared to those from the proposed EPRG Tier 2 criteria. It is found that the API and CSA codes have the same empirical limit-load criteria. As well, there are conservatisms in the proposed EPRG Tier 2. The results showed that there are various reasons why large amounts of conservatism in the allowable flaw lengths in the CSA Appendix K,2007 API 1104 Appendix A, and proposed EPRG Tier 2 girth weld defect criterion exist. Small conservatisms on failure stress can result in large conservatisms in flaw size.

  9. Regularities of radiation defects build up on oxide materials surface

    Bitenbaev, M.I.; Polyakov, A.I.; Tuseev, T.

    2005-01-01

    Analysis of experimental data by radiation defects study on different oxide elements (silicon, beryllium, aluminium, rare earth elements) irradiated by the photo-, gamma-, neutron-, alpha- radiation, protons and helium ions show, that gas adsorption process on the surface centers and radiation defects build up in metal oxide correlated between themselves. These processes were described by the equivalent kinetic equations for analysis of radiation defects build up in the different metal oxides. It was revealed in the result of the analysis: number of radiation defects are droningly increasing up to limit value with the treatment temperature growth. Constant of radicals death at ionizing radiation increases as well. Amount of surface defects in different oxides defining absorbing activity of these materials looks as: silicon oxide→beryllium oxide→aluminium oxide. So it was found, that most optimal material for absorbing system preparation is silicon oxide by it power intensity and berylium oxide by it adsorption efficiency

  10. Amino acids interacting with defected carbon nanotubes: ab initio calculations

    M. Darvish Ganji

    2016-09-01

    Full Text Available The adsorption of a number of amino acids on a defected single-walled carbon nanotube (SWCNT is investigated by using the density-functional theory (DFT calculations. The adsorption energies and equilibrium distances are calculated for various configurations such as amino acid attaching to defect sites heptagon, pentagon and hexagon in defective tube and also for several molecular orientations with respect to the nanotube surface. The results showed that amino acids prefer to be physisorbed on the outer surface of the defected nanotube with different interaction strength following the hierarchy histidine > glycine > phenylalanine > cysteine. Comparing these findings with those obtained for perfect SWCNTs reveals that the adsorption energy of the amino acids increase for adsorption onto defected CNTs. The adsorption nature has also been evaluated by means of electronics structures analysis within the Mulliken population and DOS spectra for the interacting entities.

  11. A study of defects in diamond

    Hunt, D.C.

    1999-01-01

    Defects, intrinsic and extrinsic, in natural and synthetic diamond, have been studied using Electron Paramagnetic Resonance (EPR) and optical absorption techniques. EPR measurements have been used in conjunction with infrared absorption to identify the defect-induced one-phonon infrared spectra produced by ionised single substitutional nitrogen, N s + . This N s + spectrum is characterised by a sharp peak at the Raman energy, 1332 cm -1 , accompanied by several broader resonances at 950(5), 1050(5), and 1095(5) cm -1 . Detailed concentration measurements show that a concentration of 5.5(5) ppm gives rise to an absorption of 1 cm -1 at 1332 cm -1 . The optical absorption band ND1, identified as the negative vacancy (V - ), is frequently used by diamond spectroscopists to measure the concentration of V - . Isoya has identified V - in the EPR spectra of irradiated diamond. The accuracy of EPR in determining concentrations, has been used to correlate the integrated absorption of the ND1 zero-phonon line to the concentration of V - centres. The parameter derived from this correlation is ∼16 times smaller than the previously accepted value obtained by indirect methods. A systematic study has been made - using EPR and optical absorption techniques - of synthetic type IIa diamonds, which have been irradiated with 2 MeV electrons in a specially developed dewar, allowing irradiation down to a measured sample temperature of 100K. Measurement of defect creation rates of the neutral vacancy and EPR defects, show a radical difference in the production rate of the EPR defect R2 between irradiation with the sample held at 100K and 350K. At 100K its production rate is 1.1(1) cm -1 , ∼10 times greater that at 350K. Observation of the di- -split interstitial (Ri) after irradiation at 100K proves the self-interstitial in diamond must be mobile at 100K, under the conditions of irradiation. Further study of the properties of the R2 defect (the most dominant EPR after electron

  12. Dark matter from cosmic defects on galactic scales?

    Guerreiro, N.; Carvalho, J. P. M. de; Avelino, P. P.; Martins, C. J. A. P.

    2008-01-01

    We discuss the possible dynamical role of extended cosmic defects on galactic scales, specifically focusing on the possibility that they may provide the dark matter suggested by the classical problem of galactic rotation curves. We emphasize that the more standard defects (such as Goto-Nambu strings) are unsuitable for this task but show that more general models (such as transonic wiggly strings) could in principle have a better chance. In any case, we show that observational data severely restricts any such scenarios.

  13. Serine biosynthesis and transport defects.

    El-Hattab, Ayman W

    2016-07-01

    l-serine is a non-essential amino acid that is biosynthesized via the enzymes phosphoglycerate dehydrogenase (PGDH), phosphoserine aminotransferase (PSAT), and phosphoserine phosphatase (PSP). Besides its role in protein synthesis, l-serine is a potent neurotrophic factor and a precursor of a number of essential compounds including phosphatidylserine, sphingomyelin, glycine, and d-serine. Serine biosynthesis defects result from impairments of PGDH, PSAT, or PSP leading to systemic serine deficiency. Serine biosynthesis defects present in a broad phenotypic spectrum that includes, at the severe end, Neu-Laxova syndrome, a lethal multiple congenital anomaly disease, intermediately, infantile serine biosynthesis defects with severe neurological manifestations and growth deficiency, and at the mild end, the childhood disease with intellectual disability. A serine transport defect resulting from deficiency of the ASCT1, the main transporter for serine in the central nervous system, has been recently described in children with neurological manifestations that overlap with those observed in serine biosynthesis defects. l-serine therapy may be beneficial in preventing or ameliorating symptoms in serine biosynthesis and transport defects, if started before neurological damage occurs. Herein, we review serine metabolism and transport, the clinical, biochemical, and molecular aspects of serine biosynthesis and transport defects, the mechanisms of these diseases, and the potential role of serine therapy. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Phase-enhanced defect sensitivity for EUV mask inspection

    Wang, Yow-Gwo; Miyakawa, Ryan; Chao, Weilun; Goldberg, Kenneth; Neureuther, Andy; Naulleau, Patrick

    2014-10-01

    In this paper, we present a complete study on mask blank and patterned mask inspection utilizing the Zernike phase contrast method. The Zernike phase contrast method provides in-focus inspection ability to study phase defects with enhanced defect sensitivity. However, the 90 degree phase shift in the pupil will significantly reduce the amplitude defect signal at focus. In order to detect both types of defects with a single scan, an optimized phase shift instead of 90 degree on the pupil plane is proposed to achieve an acceptable trade-off on their signal strengths. We can get a 70% of its maximum signal strength at focus for both amplitude and phase defects with a 47 degree phase shift. For SNR, the tradeoff between speckle noise and signal strength has to be considered. The SNR of phase and amplitude defects at focus can both reach 11 with 13 degree phase shift and 50% apodization. Moreover, the simulation results on patterned mask inspection of partially hidden phase defects with die-to-database inspection approach on the blank inspection tool show that the improvement of the Zernike phase method is more limited. A 40% enhancement of peak signal strength can be achieved with the Zernike phase contrast method when the defect is centered in the space, while the enhancement drops to less than 10% when it is beneath the line.

  15. Defect structure in proton-irradiated copper and nickel

    Tsukuda, Noboru; Ehrhart, P.; Jaeger, W.; Schilling, W.; Dworschak, F.; Gadalla, A.A.

    1987-01-01

    This single crystals of copper or nickel with a thickness of about 10 μm are irradiated with 3 MeV protons at room temperature and the structures of resultant defects are investigated based on measurements of the effects of irradiation on the electrical resistivity, length, lattice constants, x-ray diffraction line profile and electron microscopic observations. The measurements show that the electrical resistivity increases with irradiation dose, while leveling off at high dose due to overlapping of irradiation cascades. The lattice constants decreases, indicating that many vacancies still remain while most of the interstitial stoms are eliminated, absorbed or consumed for dislocation loop formation. The x-ray line profile undergoes broadening, which is the result of dislocation loops, dislocation networks and SFT's introduced by the proton irradiation. Various defects have different effects though they cannot be identified separately from the profile alone. A satellite peak appears at a low angle, which seems to arise from periodic defect structures that are found in electron microscopic observations. In both copper and nickel, such periodic defect structures are seen over a wide range from high to low dose. Defect-free and defect-rich domains (defect walls), 0.5 to several μm in size, are alingned parallel to the {001} plane at intervals of 60 nm. The defect walls, which consist of dislocations, dislocation loops and SFT's, is 20 - 40 nm thick. (Nogami, K.)

  16. Recovery of Frenkel defects in fcc metals

    Chaplin, R.L.; Miller, M.G.

    1976-01-01

    Because of the production of Frenkel defects occurs most readily along specific crystallographic directions in fcc structures, the recovery mechanism by which annihilation occurs should also be related to the same crystallographic orientations. The recovery path of a diffusing interstitial requires the formation of a temporary metastable state as a close-pair Frenkel defect prior to annihilation. A theoretical treatment of this scheme for interstitial-vacancy recombination shows that during the Isub(D) diffusion there is an experimentally measurable difference if the recovery forms a Isub(B) or a Isub(C) close-pair configuration in aluminum. Experimental results are given which show a difference from the theoretical predictions, and it is concluded that the assumed analytical function describing the interstitial-vacancy distribution created by a 0.4 MeV electron irradiation should be modified. (author)

  17. Risk Aversion in Game Shows

    Andersen, Steffen; Harrison, Glenn W.; Lau, Morten I.

    2008-01-01

    We review the use of behavior from television game shows to infer risk attitudes. These shows provide evidence when contestants are making decisions over very large stakes, and in a replicated, structured way. Inferences are generally confounded by the subjective assessment of skill in some games......, and the dynamic nature of the task in most games. We consider the game shows Card Sharks, Jeopardy!, Lingo, and finally Deal Or No Deal. We provide a detailed case study of the analyses of Deal Or No Deal, since it is suitable for inference about risk attitudes and has attracted considerable attention....

  18. Measuring performance at trade shows

    Hansen, Kåre

    2004-01-01

    Trade shows is an increasingly important marketing activity to many companies, but current measures of trade show performance do not adequately capture dimensions important to exhibitors. Based on the marketing literature's outcome and behavior-based control system taxonomy, a model is built...... that captures a outcome-based sales dimension and four behavior-based dimensions (i.e. information-gathering, relationship building, image building, and motivation activities). A 16-item instrument is developed for assessing exhibitors perceptions of their trade show performance. The paper presents evidence...

  19. First-Principles Investigations of Defects in Minerals

    Verma, Ashok K.

    2011-07-01

    ions vary largely among different types of defects. In particular, the O-defects introduce localized electronic states. For Mg2SiO4 polymorphs native and protonic point defects were investigated upto 30 GPa. The Mg2+-Frenkel defects in forsterite and MgO pseudo-Schottky defects in wadsleyite and ringwoodite are energetically most favorable. Mg migration is easiest in forsterite and ringwoodite whereas Si migration is easiest in wadsleyite. Protons show substantially effect on structural transition pressures and PV equations-of-states. In our work on MgO, we showed that the point defect formation is easier in grain boundary interfacial regions than in bulk and pressure increasingly stabilizes interfacial vacancies relative to bulk thereby causing as enhancement in the vacancy concentrations. Symmetric tilt grain boundaries show structural phase transitions to asymmetric tilt grain boundaries under pressure.

  20. Defects in boron ion implanted silicon

    Wu, W.K.

    1975-05-01

    The crystal defects formed after post-implantation annealing of B-ion-implanted Si irradiated at 100 keV to a moderate dose (2 x 10 14 /cm 2 ) were studied by transmission electron microscopy. Contrast analysis and annealing kinetics show at least two different kinds of linear rod-like defects along broken bracket 110 broken bracket directions. One kind either shrinks steadily remaining on broken bracket 110 broken bracket at high temperatures (greater than 850 0 C), or transforms into a perfect dislocation loop which rotates toward broken bracket 112 broken bracket perpendicular to its Burgers vector. The other kind shrinks steadily at moderate temperatures (approximately 800 0 C). The activation energy for shrinkage of the latter (3.5 +- 0.1 eV) is the same as that for B diffusion in Si, suggesting that this linear defect is a boron precipitate. There also exist a large number of perfect dislocation loops with Burgers vector a/2broken bracket 110 broken bracket. The depth distribution of all these defects was determined by stereomicroscopy. The B precipitates lying parallel to the foil surfaces are shown to be at a depth of about 3500 +- 600 A. The loops are also at the same depth, but with a broader spread, +-1100 A. Si samples containing B and samples containing no B (P-doped) were irradiated in the 650-kV electron microscope. Irradiation at 620 0 C resulted in the growth of very long linear defects in the B-doped samples but not in the others, suggesting that at 620 0 C Si interstitials produced by the electron beam replace substitutional B some of which precipitates in the form of long rods along broken bracket 110 broken bracket. (DLC)

  1. Dissociation and diffusion of hydrogen on defect-free and vacancy defective Mg (0001) surfaces: A density functional theory study

    Han, Zongying [College of Chemical and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266590 (China); Union Research Center of Fuel Cell, School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing 100083 (China); Chen, Haipeng [College of Chemical and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266590 (China); College of Mechanical and Electronic Engineering, Shandong University of Science and Technology, Qingdao 266590 (China); Zhou, Shixue, E-mail: zhoushixue66@163.com [College of Chemical and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266590 (China); College of Mechanical and Electronic Engineering, Shandong University of Science and Technology, Qingdao 266590 (China)

    2017-02-01

    Highlights: • Clarify the effect of vacancy defect on H{sub 2} dissociation on Mg (0001) surface. • Demonstrate the effects of vacancy defect on H atom diffusion. • Reveal the minimum energy diffusion path of H atom from magnesium surface into bulk. - Abstract: First-principles calculations with the density functional theory (DFT) have been carried out to study dissociation and diffusion of hydrogen on defect-free and vacancy defective Mg (0001) surfaces. Results show that energy barriers of 1.42 eV and 1.28 eV require to be overcome for H{sub 2} dissociation on defect-free and vacancy defective Mg (0001) surfaces respectively, indicating that reactivity of Mg (0001) surface is moderately increased due to vacancy defect. Besides, the existence of vacancy defect changes the preferential H atom diffusion entrance to the subsurface and reduces the diffusion energy barrier. An interesting remark is that the minimum energy diffusion path of H atom from magnesium surface into bulk is a spiral channel formed by staggered octahedral and tetrahedral interstitials. The diffusion barriers computed for H atom penetration from the surface into inner-layers are all less than 0.70 eV, which is much smaller than the activation energy for H{sub 2} dissociation on the Mg (0001) surface. This suggests that H{sub 2} dissociation is more likely than H diffusion to be rate-limiting step for magnesium hydrogenation.

  2. Tokyo Motor Show 2003; Tokyo Motor Show 2003

    Joly, E.

    2004-01-01

    The text which follows present the different techniques exposed during the 37. Tokyo Motor Show. The report points out the great tendencies of developments of the Japanese automobile industry. The hybrid electric-powered vehicles or those equipped with fuel cells have been highlighted by the Japanese manufacturers which allow considerable budgets in the research of less polluting vehicles. The exposed models, although being all different according to the manufacturer, use always a hybrid system: fuel cell/battery. The manufacturers have stressed too on the intelligent systems for navigation and safety as well as on the design and comfort. (O.M.)

  3. Facts about Congenital Heart Defects

    ... types of CHDs. The types marked with a star (*) are considered critical CHDs. Atrial Septal Defect Atrioventricular ... for Disease Control and Prevention Email Recommend Tweet YouTube Instagram Listen Watch RSS ABOUT About CDC Jobs ...

  4. Birth Defects Data and Statistics

    ... Submit" /> Information For… Media Policy Makers Data & Statistics Recommend on Facebook Tweet Share Compartir On This ... and critical. Read below for the latest national statistics on the occurrence of birth defects in the ...

  5. Defects in semiconductors

    Tilly, L.

    1993-04-01

    In this thesis, experimental results of the transition metals Ti, V, Nb, Mo, and W as impurity centres in silicon are presented. Transition metal doping was accomplished by ion implantation. Emphasis is put on energy level position, electrical and optical properties of the encountered defect levels. Junction space charge methods (JSCM) such as DLTS, photocapacitance and photocurrent techniques are employed. Three energy levels are found for the 3d-transition metals Ti(E c -0.06eV, E c -0.30eV, E v +0.26) and V(E c -0.21eV, E c -0,48e, E v +0.36eV), and for the 4d-element Nb(E c -0.29eV, E c -0.58eV, E v +0.163eV) in Silicon, whereas only one transition metal induced level is found for Mo(E v +0.30eV) and W(E v +0.38eV) respectively. Electrical and optical characteristics of Si 1-x Ge x ,0.7 7 cm -2 . The solvent Bi, used in the LPE-process, is found to be the dominant impurity element. Furthermore, liquid phase epitaxy of high purity In 0.53 Ga 0.57 As on InP, together with the properties of the Cu-induced acceptor in this material are examined. Free electron concentrations of n=5x10 14 cm -3 and electron Hall-mobilities of μ 77K = 44000 cm 2 /Vs are achieved. The energy level position of the Cu-acceptor is found to be E v +0.025eV. Photoluminescence and Hall-effect measurements, together with JSCM are the main characterization methods used. The band linups of In 0.53 Ga 0.47 As with GaAs and with InP are determined according to the Cu-acceptor energy level position in these materials. Additionally, the hydrostatic pressure dependence of the Cu-acceptor energy level position in In 0.53 Ga 0.47 As is examined. (103 refs.)

  6. Point-Defect Mediated Bonding of Pt Clusters on (5,5) Carbon Nanotubes

    Wang, J. G.; Lv, Y. A.; Li, X. N.

    2009-01-01

    The adhesion of various sizes of Pt clusters on the metallic (5,5) carbon nanotubes (CNTs) with and without the point defect has been investigated by means of density functional theory (DFT). The calculations show that the binding energies of Pt-n (n = 1-6) clusters on the defect free CNTs are more......). The stronger orbital hybridization between the Pt atom and the carbon atom shows larger charge transfers on the defective CNTs than on the defect free CNTs, which allows the strong interaction between Pt clusters and CNTs. On the basis of DFT calculations, CNTs with point defect can be used as the catalyst...

  7. Ultrasonic defect characterization using parametric-manifold mapping

    Velichko, A.; Bai, L.; Drinkwater, B. W.

    2017-06-01

    The aim of ultrasonic non-destructive evaluation includes the detection and characterization of defects, and an understanding of the nature of defects is essential for the assessment of structural integrity in safety critical systems. In general, the defect characterization challenge involves an estimation of defect parameters from measured data. In this paper, we explore the extent to which defects can be characterized by their ultrasonic scattering behaviour. Given a number of ultrasonic measurements, we show that characterization information can be extracted by projecting the measurement onto a parametric manifold in principal component space. We show that this manifold represents the entirety of the characterization information available from far-field harmonic ultrasound. We seek to understand the nature of this information and hence provide definitive statements on the defect characterization performance that is, in principle, extractable from typical measurement scenarios. In experiments, the characterization problem of surface-breaking cracks and the more general problem of elliptical voids are studied, and a good agreement is achieved between the actual parameter values and the characterization results. The nature of the parametric manifold enables us to explain and quantify why some defects are relatively easy to characterize, whereas others are inherently challenging.

  8. Topological defects from the multiverse

    Zhang, Jun; Blanco-Pillado, Jose J.; Garriga, Jaume; Vilenkin, Alexander

    2015-05-01

    Many theories of the early universe predict the existence of a multiverse where bubbles continuously nucleate giving rise to observers in their interior. In this paper, we point out that topological defects of several dimensionalities will also be produced in de Sitter like regions of the multiverse. In particular, defects could be spontaneously nucleated in our parent vacuum. We study the evolution of these defects as they collide with and propagate inside of our bubble. We estimate the present distribution of defects in the observable part of the universe. The expected number of such nearby defects turns out to be quite small, even for the highest nucleation rate. We also study collisions of strings and domain walls with our bubble in our past light cone. We obtain simulated full-sky maps of the loci of such collisions, and find their angular size distribution. Similarly to what happens in the case of bubble collisions, the prospect of detecting any collisions of our bubble with ambient defects is greatly enhanced in the case where the cosmological constant of our parent vacuum is much higher than the vacuum energy density during inflation in our bubble.

  9. Topological defects from the multiverse

    Zhang, Jun [Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford, MA 02155 (United States); Blanco-Pillado, Jose J. [Department of Theoretical Physics, University of the Basque Country UPV/EHU, 48080 Bilbao (Spain); IKERBASQUE, Basque Foundation for Science, 48013, Bilbao (Spain); Garriga, Jaume [Departament de Fisica Fonamental i Institut de Ciencies del Cosmos, Universitat de Barcelona, Marti i Franques, 1, 08028, Barcelona (Spain); Vilenkin, Alexander [Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford, MA 02155 (United States)

    2015-05-28

    Many theories of the early universe predict the existence of a multiverse where bubbles continuously nucleate giving rise to observers in their interior. In this paper, we point out that topological defects of several dimensionalities will also be produced in de Sitter like regions of the multiverse. In particular, defects could be spontaneously nucleated in our parent vacuum. We study the evolution of these defects as they collide with and propagate inside of our bubble. We estimate the present distribution of defects in the observable part of the universe. The expected number of such nearby defects turns out to be quite small, even for the highest nucleation rate. We also study collisions of strings and domain walls with our bubble in our past light cone. We obtain simulated full-sky maps of the loci of such collisions, and find their angular size distribution. Similarly to what happens in the case of bubble collisions, the prospect of detecting any collisions of our bubble with ambient defects is greatly enhanced in the case where the cosmological constant of our parent vacuum is much higher than the vacuum energy density during inflation in our bubble.

  10. Topological defects from the multiverse

    Zhang, Jun; Vilenkin, Alexander; Blanco-Pillado, Jose J.; Garriga, Jaume

    2015-01-01

    Many theories of the early universe predict the existence of a multiverse where bubbles continuously nucleate giving rise to observers in their interior. In this paper, we point out that topological defects of several dimensionalities will also be produced in de Sitter like regions of the multiverse. In particular, defects could be spontaneously nucleated in our parent vacuum. We study the evolution of these defects as they collide with and propagate inside of our bubble. We estimate the present distribution of defects in the observable part of the universe. The expected number of such nearby defects turns out to be quite small, even for the highest nucleation rate. We also study collisions of strings and domain walls with our bubble in our past light cone. We obtain simulated full-sky maps of the loci of such collisions, and find their angular size distribution. Similarly to what happens in the case of bubble collisions, the prospect of detecting any collisions of our bubble with ambient defects is greatly enhanced in the case where the cosmological constant of our parent vacuum is much higher than the vacuum energy density during inflation in our bubble

  11. Effect of sp3-hybridized defects on the oscillatory behavior of carbon nanotube oscillators

    Guo, Taiyu; Ding, Tony Weixi; Pei, Qing-Xiang; Zhang, Yong-Wei

    2011-01-01

    Using molecular dynamics simulations, we investigate the oscillatory behaviors of carbon nanotube oscillators containing sp 3 -hybridized defects formed by hydrogen chemisorption. It is found that the presence of these defects significantly affects the kinetic and potential energies of the nanotube systems, which in turn affects their oscillation periods and frequencies. We have also studied the oscillatory characteristics of the oscillators containing sp 3 -hybridized Stone-Wales defects. Our results show that it is possible to control the motion of the inner nanotube by introducing sp 3 -hybridized defects on the outer nanotube, which provides a potential way to tune the oscillatory behavior of nanotube oscillators. -- Highlights: → sp 3 -hybridized defects increase energy dissipation. → sp 3 -hybridized defects arranged in a row have stronger effect than that in a ring. → sp 3 -hybridized defects reduces the effect of SW defects.

  12. Reality show: um paradoxo nietzschiano

    Ilana Feldman

    2011-01-01

    Full Text Available

    O fenômeno dos reality shows - e a subseqüente relação entre imagem e verdade - assenta-se sobre uma série de paradoxos. Tais paradoxos podem ser compreendidos à luz do pensamento do filósofo alemão Friedrich Nietzsche, que, através dos usos de formulações paradoxais, concebia a realidade como um mundo de pura aparência e a verdade como um acréscimo ficcional, como um efeito. A ficção é então tomada, na filosofia de Nietzsche, não em seu aspecto falsificante e desrealizador - como sempre pleiteou nossa tradição metafísica -, mas como condição necessária para que certa espécie de invenção possa operar como verdade. Sendo assim, a própria expressão reality show, através de sua formulação paradoxal, engendra explicitamente um mundo de pura aparência, em que a verdade, a parte reality da proposição, é da ordem do suplemento, daquilo que se acrescenta ficcionalmente - como um adjetivo - a show. O ornamento, nesse caso, passa a ocupar o lugar central, apontando para o efeito produzido: o efeito-de-verdade. Seguindo, então, o pensamento nietzschiano e sua atualização na contemporaneidade, investigaremos de que forma os televisivos “shows de realidade” operam paradoxalmente, em consonância com nossas paradoxais práticas culturais.

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

    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

  14. Classification and printability of EUV mask defects from SEM images

    Cho, Wonil; Price, Daniel; Morgan, Paul A.; Rost, Daniel; Satake, Masaki; Tolani, Vikram L.

    2017-10-01

    Classification and Printability of EUV Mask Defects from SEM images EUV lithography is starting to show more promise for patterning some critical layers at 5nm technology node and beyond. However, there still are many key technical obstacles to overcome before bringing EUV Lithography into high volume manufacturing (HVM). One of the greatest obstacles is manufacturing defect-free masks. For pattern defect inspections in the mask-shop, cutting-edge 193nm optical inspection tools have been used so far due to lacking any e-beam mask inspection (EBMI) or EUV actinic pattern inspection (API) tools. The main issue with current 193nm inspection tools is the limited resolution for mask dimensions targeted for EUV patterning. The theoretical resolution limit for 193nm mask inspection tools is about 60nm HP on masks, which means that main feature sizes on EUV masks will be well beyond the practical resolution of 193nm inspection tools. Nevertheless, 193nm inspection tools with various illumination conditions that maximize defect sensitivity and/or main-pattern modulation are being explored for initial EUV defect detection. Due to the generally low signal-to-noise in the 193nm inspection imaging at EUV patterning dimensions, these inspections often result in hundreds and thousands of defects which then need to be accurately reviewed and dispositioned. Manually reviewing each defect is difficult due to poor resolution. In addition, the lack of a reliable aerial dispositioning system makes it very challenging to disposition for printability. In this paper, we present the use of SEM images of EUV masks for higher resolution review and disposition of defects. In this approach, most of the defects detected by the 193nm inspection tools are first imaged on a mask SEM tool. These images together with the corresponding post-OPC design clips are provided to KLA-Tencor's Reticle Decision Center (RDC) platform which provides ADC (Automated Defect Classification) and S2A (SEM

  15. Enhancing native defect sensitivity for EUV actinic blank inspection: optimized pupil engineering and photon noise study

    Wang, Yow-Gwo; Neureuther, Andrew; Naulleau, Patrick

    2016-03-01

    In this paper, we discuss the impact of optimized pupil engineering and photon noise on native defect sensitivity in EUV actinic blank inspection. Native defects include phase-dominated defects, absorber defects, and defects with a combination of phase and absorption behavior. First, we extend the idea of the Zernike phase contrast (ZPC) method and study the impact of optimum phase shift in the pupil plane on native defect sensitivity, showing a 23% signal-to-noise ratio (SNR) enhancement compare to bright field (BF) for a phase defect with 20% absorption. We also describe the possibility to increase target defect SNR on target defect sizes at the price of losing the sensitivity on smaller (non-critical) defects. Moreover, we show the advantage of the optimized phase contrast (OZPC) method over BF EUV actinic blank inspection. A single focus scan from OZPC has better inspection efficiency over BF. Second, we make a detailed comparison between the phase contrast with apodization (AZPC) method and dark field (DF) method based on defect sensitivity in the presence of both photon shot noise and camera noise. Performance is compared for a variety of photon levels, mask roughness conditions, and combinations of defect phase and absorption.

  16. Long bone reconstruction using multilevel lengthening of bone defect fragments.

    Borzunov, Dmitry Y

    2012-08-01

    This paper presents experimental findings to substantiate the use of multilevel bone fragment lengthening for managing extensive long bone defects caused by diverse aetiologies and shows its clinical introduction which could provide a solution for the problem of reducing the total treatment time. Both experimental and clinical multilevel lengthening to bridge bone defect gaps was performed with the use of the Ilizarov method only. The experimental findings and clinical outcomes showed that multilevel defect fragment lengthening could provide sufficient bone formation and reduction of the total osteosynthesis time in one stage as compared to traditional Ilizarov bone transport. The method of multilevel regeneration enabled management of critical-size defects that measured on average 13.5 ± 0.7 cm in 78 patients. The experimental and clinical results proved the efficiency of the Ilizarov non-free multilevel bone plasty that can be recommended for practical use.

  17. Thin-film limit formalism applied to surface defect absorption.

    Holovský, Jakub; Ballif, Christophe

    2014-12-15

    The thin-film limit is derived by a nonconventional approach and equations for transmittance, reflectance and absorptance are presented in highly versatile and accurate form. In the thin-film limit the optical properties do not depend on the absorption coefficient, thickness and refractive index individually, but only on their product. We show that this formalism is applicable to the problem of ultrathin defective layer e.g. on a top of a layer of amorphous silicon. We develop a new method of direct evaluation of the surface defective layer and the bulk defects. Applying this method to amorphous silicon on glass, we show that the surface defective layer differs from bulk amorphous silicon in terms of light soaking.

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

    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

  19. Behavior of duplex stainless steel casting defects under mechanical loadings

    Jayet-Gendrot, S.; Gilles, P.

    2000-01-01

    Several components in the primary circuit of pressurized water reactors are made of cast duplex stainless steels. This material contains small casting defects, mainly shrinkage cavities, due to the manufacturing process. In safety analyses, the structural integrity of the components is studied under the most severe assumptions: presence of a large defect, accidental loadings and end-of-life material properties accounting for its thermal aging embrittlement at the service temperature. The casting defects are idealized as semi-circular surface cracks or notches that have envelope dimensions. In order to assess the real severity of the casting defects under mechanical loadings, an experimental program was carried out. It consisted of testing, under both cyclic and monotonic solicitations, three-point bend specimens containing either a natural defect (in the form of a localized cluster of cavities) or a machined notch having the dimensions of the cluster's envelope. The results show that shrinkage cavities are far less harmful than envelope notches thanks to the metal bridges between cavities. Under fatigue loadings, the generalized initiation of a cluster of cavities (defined when the cluster becomes a crack of the same global size) is reached for a number of cycles that is much higher than the one leading to the initiation of a notch. In the case of monotonic loadings, specimens with casting defects offer a very high resistance to ductile tearing. The tests are analyzed in order to develop a method that takes into account the behavior of casting defects in a more realistic fashion than by an envelope crack. Various approaches are investigated, including the search of equivalent defects or of criteria based on continuum mechanics concepts, and compared with literature data. This study shows the conservatism of current safety analyses in modeling casting defects by envelope semi-elliptical cracks and contributes to the development of alternative approaches. (orig.)

  20. Determination of weld defect characteristics using focused probes

    Saglio, Robert; Touffait, A.-M.; Prot, A.-C.

    1977-01-01

    A method is described which allows, by means of an experimentally discovered law, the determination of the geometrical characteristics of the detected defects. This determination is based on the properties of focused probes, and particularly on what is called their 'effective ultrasonic beam'. The main result is the ability to describe a defect with a given and known accuracy. Examples are given which show practical applications of the method [fr

  1. Chemotaxis-defective mutants of the nematode Caenorhabditis elegans.

    Dusenbery, D B; Sheridan, R E; Russell, R L

    1975-06-01

    The technique of countercurrent separation has been used to isolate 17 independent chemotaxis-defective mutants of the nematode Caenorhabditis elegans. The mutants, selected to be relatively insensitive to the normally attractive salt NaCl, show varying degrees of residual sensitivity; some are actually weakly repelled by NaCl. The mutants are due to single gene defects, are autosomal and recessive, and identify at least five complementation groups.

  2. Defect identification for the AsGa family

    Overhof, H.; Spaeth, J.-M.

    2003-01-01

    The As Ga family consists of at least four distinctly different point defects including the technologically important EL2 defect. While the different members are easily distinguished from their MCDA spectra, the differences of the hf and shf interactions as derived from ODEPR and ODENDOR are rather small. We present ab initio calculations using the LMTO-ASA Green's function method for a variety of defect models that might be relevant for the identification of As Ga -related defects. We confirm the identification of the isolated As Ga and show that the {As Ga -X 2 } defect must be identified with the nearest-neighbor antistructure pair rather than with the {As Ga -V As } pair. For the {As Ga -X 1 } defect a distant antistructure pair is a likely candidate. For the EL2, the most important member of the As Ga family, we have not found a conclusive defect model. The recent ODENDOR data are similar to those of the distant orthorhombic {As Ga -V Ga } pair, which, however is a triple acceptor and not a donor

  3. Determination of defect content and defect profile in semiconductor heterostructures

    Zubiaga, A; Garcia, J A; Plazaola, F; Zuniga-Perez, J; Munoz-Sanjose, V

    2011-01-01

    In this article we present an overview of the technique to obtain the defects depth profile and width of a deposited layer and multilayer based on positron annihilation spectroscopy. In particular we apply the method to ZnO and ZnO/ZnCdO layers deposited on sapphire substrates. After introducing some terminology we first calculate the trend that the W/S parameters of the Doppler broadening measurements must follow, both in a qualitative and quantitative way. From this point we extend the results to calculate the width and defect profiles in deposited layer samples.

  4. Determination of defect content and defect profile in semiconductor heterostructures

    Zubiaga, A [Laboratory of Physics, HUT, PO Box 1100, 02015 TKK, Espoo (Finland); Garcia, J A; Plazaola, F [Zientzia eta Teknologia Fakultatea, Euskal Herriko Unbertsitatea, P. K. 644, 48080, Bilbao (Spain); Zuniga-Perez, J; Munoz-Sanjose, V, E-mail: fernando.plazaola@ehu.es [Universitat de Valencia, Departamento de Fisica Aplicada i Electromagnetisme, Dr. Moliner 50, 46100 Burjassot, Valencia (Spain)

    2011-01-10

    In this article we present an overview of the technique to obtain the defects depth profile and width of a deposited layer and multilayer based on positron annihilation spectroscopy. In particular we apply the method to ZnO and ZnO/ZnCdO layers deposited on sapphire substrates. After introducing some terminology we first calculate the trend that the W/S parameters of the Doppler broadening measurements must follow, both in a qualitative and quantitative way. From this point we extend the results to calculate the width and defect profiles in deposited layer samples.

  5. Defects in conformal field theory

    Billò, Marco; Gonçalves, Vasco; Lauria, Edoardo; Meineri, Marco

    2016-01-01

    We discuss consequences of the breaking of conformal symmetry by a flat or spherical extended operator. We adapt the embedding formalism to the study of correlation functions of symmetric traceless tensors in the presence of the defect. Two-point functions of a bulk and a defect primary are fixed by conformal invariance up to a set of OPE coefficients, and we identify the allowed tensor structures. A correlator of two bulk primaries depends on two cross-ratios, and we study its conformal block decomposition in the case of external scalars. The Casimir equation in the defect channel reduces to a hypergeometric equation, while the bulk channel blocks are recursively determined in the light-cone limit. In the special case of a defect of codimension two, we map the Casimir equation in the bulk channel to the one of a four-point function without defect. Finally, we analyze the contact terms of the stress-tensor with the extended operator, and we deduce constraints on the CFT data. In two dimensions, we relate the displacement operator, which appears among the contact terms, to the reflection coefficient of a conformal interface, and we find unitarity bounds for the latter.

  6. Defects in conformal field theory

    Billò, Marco [Dipartimento di Fisica, Università di Torino, and Istituto Nazionale di Fisica Nucleare - sezione di Torino,Via P. Giuria 1 I-10125 Torino (Italy); Gonçalves, Vasco [Centro de Física do Porto,Departamento de Física e Astronomia Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); ICTP South American Institute for Fundamental Research Instituto de Física Teórica,UNESP - University Estadual Paulista,Rua Dr. Bento T. Ferraz 271, 01140-070, São Paulo, SP (Brazil); Lauria, Edoardo [Institute for Theoretical Physics, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Meineri, Marco [Perimeter Institute for Theoretical Physics,Waterloo, Ontario, N2L 2Y5 (Canada); Scuola Normale Superiore, and Istituto Nazionale di Fisica Nucleare - sezione di Pisa,Piazza dei Cavalieri 7 I-56126 Pisa (Italy)

    2016-04-15

    We discuss consequences of the breaking of conformal symmetry by a flat or spherical extended operator. We adapt the embedding formalism to the study of correlation functions of symmetric traceless tensors in the presence of the defect. Two-point functions of a bulk and a defect primary are fixed by conformal invariance up to a set of OPE coefficients, and we identify the allowed tensor structures. A correlator of two bulk primaries depends on two cross-ratios, and we study its conformal block decomposition in the case of external scalars. The Casimir equation in the defect channel reduces to a hypergeometric equation, while the bulk channel blocks are recursively determined in the light-cone limit. In the special case of a defect of codimension two, we map the Casimir equation in the bulk channel to the one of a four-point function without defect. Finally, we analyze the contact terms of the stress-tensor with the extended operator, and we deduce constraints on the CFT data. In two dimensions, we relate the displacement operator, which appears among the contact terms, to the reflection coefficient of a conformal interface, and we find unitarity bounds for the latter.

  7. Pipeline defect prediction using long range ultrasonic testing and intelligent processing

    Dino Isa; Rajprasad Rajkumar

    2009-01-01

    This paper deals with efforts to improve nondestructive testing (NDT) techniques by using artificial intelligence in detecting and predicting pipeline defects such as cracks and wall thinning. The main emphasis here will be on the prediction of corrosion type defects rather than just detection after the fact. Long range ultrasonic testing will be employed, where a ring of piezoelectric transducers are used to generate torsional guided waves. Various defects such as cracks as well as corrosion under insulation (CUI) will be simulated on a test pipe. The machine learning algorithm known as the Support Vector Machine (SVM) will be used to predict and classify transducer signals using regression and large margin classification. Regression results show that the SVM is able to accurately predict future defects based on trends of previous defect. The classification performance was also exceptional showing a facility to detect defects at different depths as well as for distinguishing closely spaced defects. (author)

  8. Investigation of shinning Spot Defect on Hot-Dip Galvanized Steel Sheets

    Yonggang, Liu; Lei, Cui

    2014-01-01

    Shinning spot defects on galvanized steel sheets were studied by optical microscope, scanning electron microscope(SEM), Energy Dispersive Spectrometer (EDS) and Laser-Induced Breakdown Spectroscopy Original Position Statistic Distribution Analysis (LIBSOPA) in this study. The research shows that the coating thickness of shinning spot defects which caused by the substrate defect is much lower than normal area, and when skin passed, the shinning spot defect area can not touch with skin pass roll which result in the surface of shinning spot is flat while normal area is rough. The different coating morphologies have different effects on the reflection of light, which cause the shinning spot defects more brighter than normal area

  9. A comparative study on defect estimation using XPS and Raman spectroscopy in few layer nanographitic structures.

    Ganesan, K; Ghosh, Subrata; Gopala Krishna, Nanda; Ilango, S; Kamruddin, M; Tyagi, A K

    2016-08-10

    Defects in planar and vertically oriented nanographitic structures (NGSs) synthesized by plasma enhanced chemical vapor deposition (PECVD) have been investigated using Raman and X-ray photoelectron spectroscopy. While Raman spectra reveal the dominance of vacancy and boundary type defects respectively in vertical and planar NGSs, XPS provides additional information on vacancy related defect peaks in the C 1s spectrum, which originate from non-conjugated carbon atoms in the hexagonal lattice. Although an excellent correlation prevails between these two techniques, our results show that estimation of surface defects by XPS is more accurate than Raman analysis. Nuances of these techniques are discussed in the context of assessing defects in nanographitic structures.

  10. Fracture of vacancy-defected carbon nanotubes and their embedded nanocomposites

    Xiao Shaoping; Hou Wenyi

    2006-01-01

    In this paper, we investigate effects of vacancy defects on fracture of carbon nanotubes and carbon nanotube/aluminum composites. Our studies show that even a one-atom vacancy defect can dramatically reduce the failure stresses and strains of carbon nanotubes. Consequently, nanocomposites, in which vacancy-defected nanotubes are embedded, exhibit different characteristics from those in which pristine nanotubes are embedded. It has been found that defected nanotubes with a small volume fraction cannot reinforce but instead weaken nanocomposite materials. Although a large volume fraction of defected nanotubes can slightly increase the failure stresses of nanocomposites, the failure strains of nanocomposites are always decreased

  11. The estimation of defects influence on lifetime of NPP equipment components

    Ovchinikov, A.V.; Vasilchenko, G.S.; Rivkin, E.Y.

    1998-01-01

    Estimating the influence of defects on NPP components lifetime requires several typical operations: testing the objects without destroying the means of control, scheme of detected defects and performing calculations. The basic methods for revealing defects are ultrasonic, radiographic and visual control. A technique was developed for lifetime calculation of reactor equipment with defects using minimum information about defects and properties of material. The experience obtained during several years has shown good results. Experimental data of tests concerning destruction of construction elements showed good reliability

  12. Angiotensina-(1-7 durante o processo inicial na cascata da ovulação em bovinos Angiotensin-(1-7 during the initial process of ovulatory cascade in cattle

    Joabel Tonellotto dos Santos

    2012-10-01

    Full Text Available O presente estudo teve como objetivo avaliar o efeito da Ang-(1-7 e de seu receptor (MAS na regulação da ovulação. No experimento I, utilizando um modelo in vitro de cultivo de células foliculares, foi avaliado o efeito do tratamento com Ang-(1-7 ou do bloqueio do receptor MAS através do inibidor d-Ala7-Ang-(1-7 (A-779 na expressão de RNAm para epirregulina (Ereg; um marcador inicial do processo de ovulação em células da granulosa. No experimento II, foi utilizado um modelo in vivo de injeção intrafolicular no qual vinte vacas tiveram o ciclo estral sincronizado e, quando os folículos atingiram um diâmetro mínimo de 12mm, foi realizada a injeção intrafolicular de A-779 ou solução salina 0,9%. No momento da injeção intrafolicular, foi realizada uma aplicação IM de análogo de GnRH. A suplementação com Ang-(1-7 ou o bloqueio de seu receptor MAS em sistema de cultivo de células da granulosa não alteraram o padrão de expressão de RNAm para Ereg. A aplicação intrafolicular de A-779 (10-5M não bloqueou a ovulação quando realizada antes do início do pico esperado de LH (100% das vacas ovularam nos grupos A-779 e controle, sugerindo que a Ang-(1-7 não possui papel relevante no início da cascata ovulatória em bovinos.This study aimed to evaluate the effect of Ang-(1-7 and its receptor (MAS in the regulation of the ovulatory cascade. In the experiment I, the effect of Ang-(1-7 or d-Ala7-Ang-(1-7 (A-779; Ang-(1-7 antagonist on the epirregulin (Ereg; initial marker of ovulation process mRNA expression in granulosa cells was assessed using an in vitro model of follicular cell culture. In experiment II, it was used an in vivo intrafollicular injection model, in which twenty cows had their follicular waves synchronized and the ovarian follicular size was daily monitored by ultrasound. Follicles that reached a minimum diameter of 12mm were injected with A-779 or saline 0.9%. At the time of the intrafollicular injection

  13. Regularidade de ciclos e padrão ovulatório em jovens portadoras de anemia falciforme Regularity of cycles and ovulatory pattern in young women with sickle cell anemia

    José Wilson Viana Júnior

    2010-11-01

    between cycles (p = 0.3 were compared. There was no difference between groups in age at menarche (p = 0.05. Mean hemoglobin value was 8.4 g/dL (± 0.9 in the group of women with SCA and 12.6 g/dL (± 0.8 in the control group (p < 0.01. The frequency of ovulatory cycles was similar for cases (76.9% and controls (92.3% (p = 0.5, with a predominance of individuals with three ovulatory cycles in the control group (84.6% compared to 23.1% in the case group (p = 0.04. CONCLUSION: the findings justify the need for effective guidance for patients with SCA regarding sexual activity, the possibility of pregnancy and the alternatives for contraception.

  14. A study of the electrical properties of defects in silicon

    Blood, A.M.

    1998-01-01

    This work contains the most comprehensive qualitative and quantitative electron beam induced current (EBIC) study of recombination at contaminated defects in silicon. It is also a rigorous quantitative investigation of the effect of hydrogen on individual transition metal contaminated defects. In addition, the recombination behaviour exhibited by point and extended defects has been investigated using EBIC and deep level transient spectroscopy (DLTS). As a result of these measurements, techniques for the preparation of transition metal contaminated specimens have been refined. Successful hydrogen passivation of copper, nickel and iron contaminated silicon specimens containing oxidation-induced stacking faults has been achieved in two experimental systems. It is found that hydrogen passivates those states that are deepest in the semiconductor band gap in preference to those that are shallow. Furthermore, it has been concluded that during hydrogen passivation treatment, even at low temperatures, unwanted metallic impurities can be introduced. Three types of recombination behaviour have been identified from the defects-studied in this work and they are discussed with relevance to present recombination models. An investigation of the recombination behaviour of defects that lie in the depletion region and in the specimen bulk has concluded that the recombination type observed is independent of the depth of the defect. Evidence for the presence of compound defects showing mixed recombination behaviour type is presented. In conclusion, it is postulated that the transition metal impurities introduce a 'band of states' with a range of energies rather than a single energy state. This proposal is provided as an explanation for the recombination types found in this work and the effect of the hydrogen passivation. This work is placed in context of previous investigations into the behaviour of dislocations in silicon in the presence of transition metals, and the ability of

  15. Micromagnetic simulation of exploratory magnetic logic device with missing corner defect

    Yang, Xiaokuo, E-mail: yangxk0123@163.com; Cai, Li; Zhang, Bin; Cui, Huanqing; Zhang, Mingliang

    2015-11-15

    Magnetic film nanostructures are attractive components of nonvolatile magnetoresistive memories and nanomagnet logic circuits. Recently, we studied switching properties (i.e., null logic preserving) of rectangle shape nanomagnet subjected to fabrication imperfections. Specifically, we presented typical missing corner material-related imperfections and adopted an isosceles triangle to model this defect for nanomagnets. Micromagnetic simulation shows that this kind of imperfections modeling method agrees well with previous experimental observations. Using the proposed defect modeling scheme, we investigate in detail the switching characteristics of different defective stand-alone and coupled nanomagnets. The results suggest that the state transition of defective nanomagnet element highly depends on defect type and device’s aspect ratio, and the defect type B{sub d} needs the largest coercive field, while the defect type D requires the largest null field for switching. These findings can provide key technical parameters and guides for nanomagnet logic circuit design. - Highlights: • We have modeled missing corner defect issue for nanomagnet logic device. • The logic state of defective NML element highly depends on defect type and AR. • The NML device with defect type B{sub d} needs the largest coercive field to reverse state. • The defect type D in the NML devices requires the largest null field to switch.

  16. Atomic structure of defects in GaN:Mg grown with Ga polarity

    Liliental-Weber, Z.; Tomaszewicz, T.; Zakharov, D.; Jasinski, J.; O'Keefe, M.A.; Hautakangas, S.; Laakso, A.; Saarinen, K.

    2003-01-01

    Electron microscope phase images, produced by direct reconstruction of the scattered electron wave from a focal series of high-resolution images, were used to determine the nature of defects formed in GaN:Mg crystals. We studied bulk crystals grown from dilute solutions of atomic nitrogen in liquid gallium at high pressure and thin films grown by the MOCVD method. All the crystals were grown with Ga-polarity. In both types of samples the majority of defects were three dimensional Mg-rich hexagonal pyramids with bases on the (0001) plane and six walls on {11(und 2)3} planes seen in cross-section as triangulars. Some other defects appear in cross-section as trapezoidal (rectangular) defects as a result of presence of truncated pyramids. Both type of defects have hollow centers. They are decorated by Mg on all six side walls and a base. The GaN which grows inside on the defect walls shows polarity inversion. It is shown that change of polarity starts from the defect tip and propagates to the base, and that the stacking sequence changes from ab in the matrix to bc inside the defect. Exchange of the Ga sublattice with the N sublattice within the defect leads to 0.6 ± 0.2(angstrom) displacement between Ga sublattices outside and inside the defects. It is proposed that lateral overgrowth of the cavities formed within the defect takes place to restore matrix polarity on the defect base

  17. Theory of Defects in Semiconductors

    Drabold, David A

    2007-01-01

    Semiconductor science and technology is the art of defect engineering. The theoretical modeling of defects has improved dramatically over the past decade. These tools are now applied to a wide range of materials issues: quantum dots, buckyballs, spintronics, interfaces, amorphous systems, and many others. This volume presents a coherent and detailed description of the field, and brings together leaders in theoretical research. Today's state-of-the-art, as well as tomorrow’s tools, are discussed: the supercell-pseudopotential method, the GW formalism,Quantum Monte Carlo, learn-on-the-fly molecular dynamics, finite-temperature treatments, etc. A wealth of applications are included, from point defects to wafer bonding or the propagation of dislocation.

  18. Defect CFTs and holographic multiverse

    Fiol, Bartomeu, E-mail: bfiol@ub.edu [Departament de Física Fonamental i Institut de Ciències del Cosmos, Universitat de Barcelona, Martí i Franquès 1, 08193 Barcelona (Spain)

    2010-07-01

    We investigate some aspects of a recent proposal for a holographic description of the multiverse. Specifically, we focus on the implications on the suggested duality of the fluctuations of a bubble separating two universes with different cosmological constants. We do so by considering a similar problem in a 2+1 CFT with a codimension one defect, obtained by an M5-brane probe embedding in AdS{sub 4} × S{sup 7}, and studying its spectrum of fluctuations. Our results suggest that the kind of behavior required by the spectrum of bubble fluctuations is not likely to take place in defect CFTs with an AdS dual, although it might be possible if the defect supports a non-unitary theory.

  19. Defect CFTs and holographic multiverse

    Fiol, Bartomeu

    2010-01-01

    We investigate some aspects of a recent proposal for a holographic description of the multiverse. Specifically, we focus on the implications on the suggested duality of the fluctuations of a bubble separating two universes with different cosmological constants. We do so by considering a similar problem in a 2+1 CFT with a codimension one defect, obtained by an M5-brane probe embedding in AdS 4 × S 7 , and studying its spectrum of fluctuations. Our results suggest that the kind of behavior required by the spectrum of bubble fluctuations is not likely to take place in defect CFTs with an AdS dual, although it might be possible if the defect supports a non-unitary theory

  20. Rail inspection of RCF defects

    Z. Popović

    2013-10-01

    Full Text Available Rail defects due to rolling contact fatigue (RCF threaten the traffic safety around the world. That hazard is more distinct on railways without adequate maintenance strategy. Realization of interoperability of European railway network demands from every infrastructure manager to have a maintenance plan for the infrastructure subsystem. Besides that, this plan includes rail inspection and strategy against RCF defects. This paper emphasizes the importance of rail inspection and early detection of RCF because the most of RCF crack should be removed in rail grinding campaigns (preventive, cyclical and corrective activities during the whole rail service life.

  1. Defect characterization with positron annihilation

    Granatelli, L.; Lynn, K.G.

    1980-01-01

    Positron annihilation in metal crystals is reviewed. A brief introduction to the positron annihilation technique is presented first. Then the ability of the positron technique to perform microstructural characterization of four types of lattice defects (vacancies, voids, dislocations, grain boundaries) is discussed. It is frequently not possible to obtain samples that contain only one type of defect in nonnegligible concentrations. Such situations exist for some alloys and for fatigued metal samples. Finally, the current limitations and some future prospects of the technique are presented. 79 references, 14 figures, 1 table

  2. Nitrotyrosine adsorption on defective graphene: A density functional theory study

    Majidi, R.; Karami, A. R.

    2015-06-01

    We have applied density functional theory to study adsorption of nitrotyrosine on perfect and defective graphene sheets. The graphene sheets with Stone-Wales (SW) defect, pentagon-nonagon (5-9) single vacancy, and pentagon-octagon-pentagon (5-8-5) double vacancy were considered. The calculations of adsorption energy showed that nitrotyrosine presents a more strong interaction with defective graphene rather than with perfect graphene sheet. The order of interaction strength is: SW>5-9>5-8-5>perfect graphene. It is found that the electronic properties of perfect and defective graphene are sensitive to the presence of nitrotyrosine. Hence, graphene sheets can be considered as a good sensor for detection of nitrotyrosine molecule which is observed in connection with several human disorders, such as Parkinson's and Alzheimer's disease.

  3. Left-right correlation in coupled F-center defects.

    Janesko, Benjamin G

    2016-08-07

    This work explores how left-right correlation, a textbook problem in electronic structure theory, manifests in a textbook example of electrons trapped in crystal defects. I show that adjacent F-center defects in lithium fluoride display symptoms of "strong" left-right correlation, symptoms similar to those seen in stretched H2. Simulations of UV/visible absorption spectra qualitatively fail to reproduce experiment unless left-right correlation is taken into account. This is of interest to both the electronic structure theory and crystal-defect communities. Theorists have a new well-behaved system to test their methods. Crystal-defect groups are cautioned that the approximations that successfully model single F-centers may fail for adjacent F-centers.

  4. Left-right correlation in coupled F-center defects

    Janesko, Benjamin G.

    2016-01-01

    This work explores how left-right correlation, a textbook problem in electronic structure theory, manifests in a textbook example of electrons trapped in crystal defects. I show that adjacent F-center defects in lithium fluoride display symptoms of “strong” left-right correlation, symptoms similar to those seen in stretched H 2 . Simulations of UV/visible absorption spectra qualitatively fail to reproduce experiment unless left-right correlation is taken into account. This is of interest to both the electronic structure theory and crystal-defect communities. Theorists have a new well-behaved system to test their methods. Crystal-defect groups are cautioned that the approximations that successfully model single F-centers may fail for adjacent F-centers.

  5. Ultrasonic characterization of defective porcelain tiles

    Eren, E.

    2012-08-01

    Full Text Available The aim of this work is the optimization of ultrasonic methods in the non-destructive testing of sintered porcelain tiles containing defects. For this reason, a silicon nitride ball, carbon black and PMMA (Polymethylmethacrylate were imbedded in porcelain tile granules before pressing to make special defects in tiles. After sintering at 1220ºC, the time of flight of the ultrasonic waves and ultrasonic signal amplitudes through the sintered porcelain tiles were measured by a contact ultrasonic transducer operating on pulse-echo mode. This method can allow for defect detection using the A-scan. The results of the test showed that the amplitude of the received peak for a defective part is smaller than for a part which has no defects. Depending on the size, shape and position of the defect, its peak can be detected. Additionally, an immersion pulse-echo C-scan method was also used to differentiate between defects in porcelain tiles. By using this technique, it is possible to determine the place and shape of defects. To support the results of the ultrasonic investigation, a SEM characterization was also made.

    El fin principal de este trabajo es la optimización de métodos ultrasónicos en la prueba no destructiva de azulejos sinterizados de porcelana que contienen defectos. Por lo tanto, bolas del nitruro de silicio, negros de carbón y PMMA (polimetilmetacrilato fueron encajados en gránulos del azulejo de porcelana antes de presionar para hacer defectos especiales en azulejos. Después de sinterizado en 1220ºC, el tiempo de vuelo de las ondas ultrasónicas fue medido a través del azulejo sinterizado de la porcelana. El tiempo del vuelo de ondas ultrasónicas fue medido por un transductor de contacto ultrasónico operando en modo eco-pulso. Este método puede permitir la detección de defectos usando escaneo-A. Los resultados de la prueba demostraron que la amplitud del pico recibido por partes defectuosas es más pequeño que la parte

  6. A new fundamental hydrogen defect in alkali halides

    Morato, S.P.; Luety, F.

    1978-01-01

    Atom hydrogen in neutral (H 0 ) and negative (H - ) form on substitutional and interstitial lattice sites gives rise to well characterized model defects in alkali-halides (U,U 1 ,U 2 ,U 3 centers), which have been extensively investigated in the past. When studying the photo-decomposition of OH - defects, a new configuration of atomic charged hidrogen was discovered, which can be produced in large quantities in the crystal and is apparently not connected to any other impurity. This new hidrogen defect does not show any pronounced electronic absorption, but displays a single sharp local mode band (at 1114cm -1 in KCl) with a perfect isotope shift. The defect can be produced by various UV or X-ray techniques in crystais doped with OH - , Sh - or H - defects. A detailed study of its formation kinetics at low temperature shows that it is primarily formed by the reaction of a mobile CI 2 - crowdion (H-center) with hidrogen defects [pt

  7. Heat-Treatment of Defective UiO-66 from Modulated Synthesis: Adsorption and Stability Studies

    Jiao, Yang; Liu, Yang; Zhu, Guanghui; Hungerford, Julian T.; Bhattacharyya, Souryadeep

    2017-01-01

    Defect engineering in metal-organic frameworks (MOFs) is an emerging strategy that can be used to control physical or chemical characteristics of MOFs, including adsorption behavior and textural, mechanical, and conductive properties. Understanding the impact of defects on textural properties and chemical stability of MOFs is imperative to the development of MOFs with tunable defect sites. In this work, systematic adsorption measurements were performed with three adsorbate molecules (SO 2 , benzene, and cyclohexane) to investigate changes in the pore size of defective UiO-66. Compared to the parent UiO-66, the defective UiO-66 shows significant changes in adsorption capacities among the selected adsorbate molecules, demonstrating that pore size is significantly enlarged by the missing cluster defects. BET surface area analysis and DFT calculations were also performed to interrogate the chemical stability of the defective MOFs after exposure to water and acidic environments. This work shows that pore size can be tuned as a function of defect concentration. Further, it is shown that the structural incorporation of trifluoroacetate groups in defective UiO-66 leads to an increase in average pore size without sacrificing chemical stability toward water and acidic species. The results of this work advance the understanding of textural properties and chemical stability of defect-engineered MOFs and also suggest a preparation method for synthesizing defective but stable MOFs.

  8. Implications of permeation through intrinsic defects in graphene on the design of defect-tolerant membranes for gas separation.

    Boutilier, Michael S H; Sun, Chengzhen; O'Hern, Sean C; Au, Harold; Hadjiconstantinou, Nicolas G; Karnik, Rohit

    2014-01-28

    Gas transport through intrinsic defects and tears is a critical yet poorly understood phenomenon in graphene membranes for gas separation. We report that independent stacking of graphene layers on a porous support exponentially decreases flow through defects. On the basis of experimental results, we develop a gas transport model that elucidates the separate contributions of tears and intrinsic defects on gas leakage through these membranes. The model shows that the pore size of the porous support and its permeance critically affect the separation behavior, and reveals the parameter space where gas separation can be achieved regardless of the presence of nonselective defects, even for single-layer membranes. The results provide a framework for understanding gas transport in graphene membranes and guide the design of practical, selectively permeable graphene membranes for gas separation.

  9. Corrosion Behavior of X80 Steel with Coupled Coating Defects under Alternating Current Interference in Alkaline Environment.

    Li, Zhong; Li, Caiyu; Qian, Hongchang; Li, Jun; Huang, Liang; Du, Cuiwei

    2017-06-28

    The corrosion behavior of X80 steel in the presence of coupled coating defects was simulated and studied under the interference of alternating current (AC) in an alkaline environment. The results from electrochemical measurements showed that the electrode potential of the coating defect with the smaller exposed area was lower than that with the larger area, which indicated that the steel with the smaller coating defect was more prone to corrosion. The result of weight loss tests also showed that the smaller coating defect had induced a higher corrosion rate. However, the corrosion rate of X80 steel at the larger coating defect decreased gradually with the increase of the larger defect area at a constant smaller defect area. The corrosion morphology images showed that the coating defects with smaller areas suffered from more severe pitting corrosion.

  10. What Are Congenital Heart Defects?

    ... a baby with a congenital heart defect. Family history and genetics Congenital heart disease is not usually passed along ... you or your child to a specialist in genetic testing. Cardiac MRI to diagnose a ... Factors to review family history, smoking, and medicines that increase your risk of ...

  11. Nuclear Pasta: Topology and Defects

    da Silva Schneider, Andre; Horowitz, Charles; Berry, Don; Caplan, Matt; Briggs, Christian

    2015-04-01

    A layer of complex non-uniform phases of matter known as nuclear pasta is expected to exist at the base of the crust of neutron stars. Using large scale molecular dynamics we study the topology of some pasta shapes, the formation of defects and how these may affect properties of neutron star crusts.

  12. Ocular defects in cerebral palsy

    Katoch Sabita

    2007-01-01

    Full Text Available There is a high prevalence of ocular defects in children with developmental disabilities. This study evaluated visual disability in a group of 200 cerebral palsy (CP patients and found that 68% of the children had significant visual morbidity. These findings emphasize the need for an early ocular examination in patients with CP.

  13. Characterization of point defects in monolayer arsenene

    Liang, Xiongyi; Ng, Siu-Pang; Ding, Ning; Wu, Chi-Man Lawrence

    2018-06-01

    Topological defects that are inevitably found in 2D materials can dramatically affect their properties. Using density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) method, the structural, thermodynamic, electronic and magnetic properties of six types of typical point defects in arsenene, i.e. the Stone-Wales defect, single and double vacancies and adatoms, were systemically studied. It was found that these defects were all more easily generated in arsenene with lower formation energies than those with graphene and silicene. Stone-Wales defects can be transformed from pristine arsenene by overcoming a barrier of 2.19 eV and single vacancy defects tend to coalesce into double vacancy defects by diffusion. However, a type of adatom defect does not exhibit kinetic stability at room temperature. In addition, SV defects and another type of adatom defect can remarkably affect the electronic and magnetic properties of arsenene, e.g. they can introduce localized states near the Fermi level, as well as a strongly local magnetic moment due to dangling bond and unpaired electron. Furthermore, the simulated scanning tunneling microscopy (STM) and Raman spectroscopy were computed and the types of point defects can be fully characterized by correlating the STM images and Raman spectra to the defective atomistic structures. The results provide significant insights to the effect of defects in arsenene for potential applications, as well as identifications of two helpful tools (STM and Raman spectroscopy) to distinguish the type of defects in arsenene for future experiments.

  14. Role of the bond defect for structural transformations between crystalline and amorphous silicon: A molecular-dynamics study

    Stock, D. M.; Weber, B.; Gaertner, K.

    2000-01-01

    The relation between the bond defect, which is a topological defect, and structural transformations between crystalline and amorphous silicon, is studied by molecular-dynamics simulations. The investigation of 1-keV boron implantation into crystalline silicon proves that the bond defect can also be generated directly by collisional-induced bond switching in addition to its formation by incomplete recombination of primary defects. This supports the assumption that the bond defect may play an important role in the amorphization process of silicon by light ions. The analysis of the interface between (001) silicon and amorphous silicon shows that there are two typical defect configurations at the interface which result from two different orientations of the bond defect with respect to the interface. Thus the bond defect appears to be a characteristic structural feature of the interface. Moreover, annealing results indicate that the bond defect acts as a growth site for interface-mediated crystallization

  15. The effect of bulk/surface defects ratio change on the photocatalysis of TiO_2 nanosheet film

    Wang, Fangfang; Ge, Wenna; Shen, Tong; Ye, Bangjiao; Fu, Zhengping; Lu, Yalin

    2017-01-01

    Highlights: • The defect behaviors of TiO_2 nanosheet array films were studied by positron annihilation spectroscopy. • Different bulk/surface defect ratios were realized by annealing at different temperature. • It was concluded that bulk defects are mainly Ti"3"+ vacancy defects. • The separation efficiency of photogenerated electrons and holes could be significantly improved by optimizing the bulk/surface defects ratio. - Abstract: The photocatalysis behavior of TiO_2 nanosheet array films was studied, in which the ratio of bulk/surface defects were adjusted by annealing at different temperature. Combining positron annihilation spectroscopy, EPR and XPS, we concluded that the bulk defects belonged to Ti"3"+ related vacancy defects. The results show that the separation efficiency of photogenerated electrons and holes could be significantly improved by optimizing the bulk/surface defects ratio of TiO_2 nanosheet films, and in turn enhancing the photocatalysis behaviors.

  16. The effect of bulk/surface defects ratio change on the photocatalysis of TiO{sub 2} nanosheet film

    Wang, Fangfang [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); Ge, Wenna [State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei 230026 (China); Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China); Shen, Tong [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); Ye, Bangjiao [State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei 230026 (China); Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China); Fu, Zhengping, E-mail: fuzp@ustc.edu.cn [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); Lu, Yalin, E-mail: yllu@ustc.edu.cn [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); Synergetic Innovation Center of Quantum Information & Stop Quantum Physics, University of Science and Technology of China, Hefei 230026 (China); National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026, Anhui (China)

    2017-07-15

    Highlights: • The defect behaviors of TiO{sub 2} nanosheet array films were studied by positron annihilation spectroscopy. • Different bulk/surface defect ratios were realized by annealing at different temperature. • It was concluded that bulk defects are mainly Ti{sup 3+} vacancy defects. • The separation efficiency of photogenerated electrons and holes could be significantly improved by optimizing the bulk/surface defects ratio. - Abstract: The photocatalysis behavior of TiO{sub 2} nanosheet array films was studied, in which the ratio of bulk/surface defects were adjusted by annealing at different temperature. Combining positron annihilation spectroscopy, EPR and XPS, we concluded that the bulk defects belonged to Ti{sup 3+} related vacancy defects. The results show that the separation efficiency of photogenerated electrons and holes could be significantly improved by optimizing the bulk/surface defects ratio of TiO{sub 2} nanosheet films, and in turn enhancing the photocatalysis behaviors.

  17. Influence of growth temperature on bulk and surface defects in hybrid lead halide perovskite films

    Peng, Weina; Anand, Benoy; Liu, Lihong; Sampat, Siddharth; Bearden, Brandon E.; Malko, Anton V.; Chabal, Yves J.

    2016-01-01

    The rapid development of perovskite solar cells has focused its attention on defects in perovskites, which are gradually realized to strongly control the device performance. A fundamental understanding is therefore needed for further improvement in this field. Recent efforts have mainly focused on minimizing the surface defects and grain boundaries in thin films. Using time-resolved photoluminescence spectroscopy, we show that bulk defects in perovskite samples prepared using vapor assisted solution process (VASP) play a key role in addition to surface and grain boundary defects. The defect state density of samples prepared at 150 °C (~1017 cm-3) increases by 5 fold at 175 °C even though the average grains size increases slightly, ruling out grain boundary defects as the main mechanism for the observed differences in PL properties upon annealing. Upon surface passivation using water molecules, the PL intensity and lifetime of samples prepared at 200 °C are only partially improved, remaining significantly lower than those prepared at 150 °C. Thus, the present study indicates that the majority of these defect states observed at elevated growth temperatures originates from bulk defects and underscores the importance to control the formation of bulk defects together with grain boundary and surface defects to further improve the optoelectronic properties of perovskites.The rapid development of perovskite solar cells has focused its attention on defects in perovskites, which are gradually realized to strongly control the device performance. A fundamental understanding is therefore needed for further improvement in this field. Recent efforts have mainly focused on minimizing the surface defects and grain boundaries in thin films. Using time-resolved photoluminescence spectroscopy, we show that bulk defects in perovskite samples prepared using vapor assisted solution process (VASP) play a key role in addition to surface and grain boundary defects. The defect state

  18. Defects in medical X-ray equipment

    Eder, H.; Wahl, H.; Troeger, W.

    1979-01-01

    A careful estimate of the effects on the genetically significant radiation load shows that it is in the same order of magnitude as the increase in the skin dose area product. This is to say that of the genetically significant radiation dose of about 500 mJ/kg (50 mrem) per year and person due to medical X-ray diagnostics, about 75 mJ/kg (7.5 mrem) are due to serious defects in X-ray equipment. (orig.) [de

  19. Nanocarbon: Defect Architectures and Properties

    Vuong, Amanda

    The allotropes of carbon make its solid phases amongst the most diverse of any element. It can occur naturally as graphite and diamond, which have very different properties that make them suitable for a wide range of technological and commercial purposes. Recent developments in synthetic carbon include Highly Oriented Pyrolytic Graphite (HOPG) and nano-carbons, such as fullerenes, nanotubes and graphene. The main industrial application of bulk graphite is as an electrode material in steel production, but in purified nuclear graphite form, it is also used as a moderator in Advanced Gas-cooled Reactors across the United Kingdom. Both graphene and graphite are damaged over time when subjected to bombardment by electrons, neutrons or ions, and these have a wide range of effects on their physical and electrical properties, depending on the radiation flux and temperature. This research focuses on intrinsic defects in graphene and dimensional change in nuclear graphite. The method used here is computational chemistry, which complements physical experiments. Techniques used comprise of density functional theory (DFT) and molecular dynamics (MD), which are discussed in chapter 2 and chapter 3, respectively. The succeeding chapters describe the results of simulations performed to model defects in graphene and graphite. Chapter 4 presents the results of ab initio DFT calculations performed to investigate vacancy complexes that are formed in AA stacked bilayer graphene. In AB stacking, carbon atoms surrounding the lattice vacancies can form interlayer structures with sp2 bonding that are lower in energy compared to in-plane reconstructions. From the investigation of AA stacking, sp2 interlayer bonding of adjacent multivacancy defects in registry creates a type of stable sp2 bonded wormhole between the layers. Also, a new class of mezzanine structure characterised by sp3 interlayer bonding, resembling a prismatic vacancy loop has also been identified. The mezzanine, which is a

  20. Effect of triangular vacancy defect on thermal conductivity and thermal rectification in graphene nanoribbons

    Yang, Ping, E-mail: yangpingdm@ujs.edu.cn [Laboratory of Advanced Manufacturing and Reliability for MEMS/NEMS/OEDS, Jiangsu University, Zhenjiang 212013 (China); Li, Xialong; Zhao, Yanfan [Laboratory of Advanced Manufacturing and Reliability for MEMS/NEMS/OEDS, Jiangsu University, Zhenjiang 212013 (China); Yang, Haiying [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Wang, Shuting, E-mail: wangst@mail.hust.edu.cn [School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China)

    2013-11-01

    We investigate the thermal transport properties of armchair graphene nanoribbons (AGNRs) possessing various sizes of triangular vacancy defect within a temperature range of 200–600 K by using classical molecular dynamics simulation. The results show that the thermal conductivities of the graphene nanoribbons decrease with increasing sizes of triangular vacancy defects in both directions across the whole temperature range tested, and the presence of the defect can decrease the thermal conductivity by more than 40% as the number of removed cluster atoms is increased to 25 (1.56% for vacancy concentration) owing to the effect of phonon–defect scattering. In the meantime, we find the thermal conductivity of defective graphene nanoribbons is insensitive to the temperature change at higher vacancy concentrations. Furthermore, the dependence of temperatures and various sizes of triangular vacancy defect for the thermal rectification ration are also detected. This work implies a possible route to achieve thermal rectifier for 2D materials by defect engineering.

  1. Tunable single photonic defect-mode in cholesteric liquid crystals with laser-induced local modifications of helix

    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

  2. Quasi-one-dimensional metals on semiconductor surfaces with defects

    Hasegawa, Shuji

    2010-01-01

    Several examples are known in which massive arrays of metal atomic chains are formed on semiconductor surfaces that show quasi-one-dimensional metallic electronic structures. In this review, Au chains on Si(557) and Si(553) surfaces, and In chains on Si(111) surfaces, are introduced and discussed with regard to the physical properties determined by experimental data from scanning tunneling microscopy (STM), angle-resolved photoemission spectroscopy (ARPES) and electrical conductivity measurements. They show quasi-one-dimensional Fermi surfaces and parabolic band dispersion along the chains. All of them are known from STM and ARPES to exhibit metal-insulator transitions by cooling and charge-density-wave formation due to Peierls instability of the metallic chains. The electrical conductivity, however, reveals the metal-insulator transition only on the less-defective surfaces (Si(553)-Au and Si(111)-In), but not on a more-defective surface (Si(557)-Au). The latter shows an insulating character over the whole temperature range. Compared with the electronic structure (Fermi surfaces and band dispersions), the transport property is more sensitive to the defects. With an increase in defect density, the conductivity only along the metal atomic chains was significantly reduced, showing that atomic-scale point defects decisively interrupt the electrical transport along the atomic chains and hide the intrinsic property of transport in quasi-one-dimensional systems.

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

    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

  4. Crystal defect studies using x-ray diffuse scattering

    Larson, B.C.

    1980-01-01

    Microscopic lattice defects such as point (single atom) defects, dislocation loops, and solute precipitates are characterized by local electronic density changes at the defect sites and by distortions of the lattice structure surrounding the defects. The effect of these interruptions of the crystal lattice on the scattering of x-rays is considered in this paper, and examples are presented of the use of the diffuse scattering to study the defects. X-ray studies of self-interstitials in electron irradiated aluminum and copper are discussed in terms of the identification of the interstitial configuration. Methods for detecting the onset of point defect aggregation into dislocation loops are considered and new techniques for the determination of separate size distributions for vacancy loops and interstitial loops are presented. Direct comparisons of dislocation loop measurements by x-rays with existing electron microscopy studies of dislocation loops indicate agreement for larger size loops, but x-ray measurements report higher concentrations in the smaller loop range. Methods for distinguishing between loops and three-dimensional precipitates are discussed and possibilities for detailed studies considered. A comparison of dislocation loop size distributions obtained from integral diffuse scattering measurements with those from TEM show a discrepancy in the smaller sizes similar to that described above

  5. Elastic dipoles of point defects from atomistic simulations

    Varvenne, Céline; Clouet, Emmanuel

    2017-12-01

    The interaction of point defects with an external stress field or with other structural defects is usually well described within continuum elasticity by the elastic dipole approximation. Extraction of the elastic dipoles from atomistic simulations is therefore a fundamental step to connect an atomistic description of the defect with continuum models. This can be done either by a fitting of the point-defect displacement field, by a summation of the Kanzaki forces, or by a linking equation to the residual stress. We perform here a detailed comparison of these different available methods to extract elastic dipoles, and show that they all lead to the same values when the supercell of the atomistic simulations is large enough and when the anharmonic region around the point defect is correctly handled. But, for small simulation cells compatible with ab initio calculations, only the definition through the residual stress appears tractable. The approach is illustrated by considering various point defects (vacancy, self-interstitial, and hydrogen solute atom) in zirconium, using both empirical potentials and ab initio calculations.

  6. Crystal defect studies using x-ray diffuse scattering

    Larson, B.C.

    1980-01-01

    Microscopic lattice defects such as point (single atom) defects, dislocation loops, and solute precipitates are characterized by local electronic density changes at the defect sites and by distortions of the lattice structure surrounding the defects. The effect of these interruptions of the crystal lattice on the scattering of x-rays is considered in this paper, and examples are presented of the use of the diffuse scattering to study the defects. X-ray studies of self-interstitials in electron irradiated aluminum and copper are discussed in terms of the identification of the interstitial configuration. Methods for detecting the onset of point defect aggregation into dislocation loops are considered and new techniques for the determination of separate size distributions for vacancy loops and interstitial loops are presented. Direct comparisons of dislocation loop measurements by x-rays with existing electron microscopy studies of dislocation loops indicate agreement for larger size loops, but x-ray measurements report higher concentrations in the smaller loop range. Methods for distinguishing between loops and three-dimensional precipitates are discussed and possibilities for detailed studies considered. A comparison of dislocation loop size distributions obtained from integral diffuse scattering measurements with those from TEM show a discrepancy in the smaller sizes similar to that described above.

  7. Quantitative Evaluation of Remote Field Eddy Current Defect Signals

    Jeong, Jin Oh; Yi, Jae Kyung; Kim, Hyoung Jean

    2000-01-01

    The remote field eddy current (RFEC) inspection was performed on the ductile cast iron pipes with nominal outer diameter of 100mm, which were machined with various shapes and sizes of defects. Ductile cast iron pipes which are used as water supply pipe have the non-uniform thickness and asymmetric cross section due to relatively high degree of allowable errors during the manufacturing processes. These characteristics of ductile cast in pipes cause the long range background noises in RFEC signals along the pipe. In this study, tile machined defects in pipes were effectively classified by the moving window average (MWA) method which eliminated the long-range noise. The voltage plane polar plots (VPPP) method was used to quantitatively evaluate the depth and circumferential degree of defects. The VPPP signatures showed that the angle between defect signature and the normalized in-phase component on the VPPP is linear to the depth of defects. The nondestructive RFEC technique proved to be capable of quantitatively evaluating the machined defects of underground water supply pipe

  8. Behavior of duplex stainless steel casting defects under mechanical loadings

    Jayet-Gendrot, S [Electricite de France, 77 - Moret-sur-Loing (France). Dept. of Materials Study; Gilles, P; Migne, C [Societe Franco-Americaine de Constructions Atomiques (FRAMATOME), 92 - Paris-La-Defense (France)

    1997-04-01

    Several components in the primary circuit of pressurized water reactors are made of cast duplex stainless steels. This material contains small casting defects, mainly shrinkage cavities, due to the manufacturing process. In safety analyses, the structural integrity of the components is studied. In order to assess the real severity of the casting defects under mechanical loadings, an experimental program was carried out. It consisted of testing, under both cyclic and monotonic solicitations, three-point bend specimens containing either a natural defect (in the form of a localized cluster of cavities) or a machined notch having the dimensions of the cluster`s envelope. The tests are analyzed in order to develop a method that takes into account the behavior of castings defects in a more realistic fashion than by an envelope crack. Various approaches are investigated, including the search of equivalent defects or of criteria based on continuum mechanics concepts, and compared with literature data. This study shows the conservatism of current safety analyses in modelling casting defects by envelope semi-elliptical cracks and contributes to the development of alternative approaches. (author) 18 refs.

  9. Light-induced defects in hybrid lead halide perovskite

    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.

  10. Irradiated strut allografts for reconstructing tumour defects: how effective?

    Astrid Lobo Gajiwala; Manish Agarwal; Ajay Puri; Cynthia D Lima

    2008-01-01

    Full text: Allografts are biological options for reconstructing large bone defects. We report our experience with 87 irradiated (25 kGy of gamma radiation) strut allografts used in various defects following tumour surgery. Reconstruction in 35 full segment defects involved 22 full segment allografts used alone, 4 allograft prosthetic composites (APC) and 9 allografts combined with a vascularized fibula. Twelve partial segment defects were reconstructed with allograft struts (including 2 APC). Full segment allograft struts (mainly fibulae) were used in 40 contained post-curettage defects. The cases were studied for time to incorporation and complications. The follow-up ranged from 12 to 72 months. Of the 26 full segment defects where allograft alone or APC was used, 2 were lost to follow-up, 5 died before incorporation and 3 grafts were removed (2 infection and 1 local recurrence). Six united primarily at 2-4 years. Seven patients with non union were autografted at both junctions resulting in 6 unions. One patient had early plate breakage and refused further treatment. One allograft fractured after union after autografting. Two of 4 APC also united. In contrast, the 9 allograft-vascularized fibula combinations showed unambiguous incorporation between 5-9 months with only one junction requiring bone grafting. Of the 12 partial segment struts, barring one removed for infection, 11 have completely incorporated. Thirty one out of 40 struts placed within contained post curettage defects have incorporated (2 removed for infection and seven lost to follow-up). There were total 6 infections (7%) 4 of which occurred 1-2 years after surgery. Irradiated full segment struts alone incorporate poorly and are best used combined with a live fibula. Irradiated full and partial segment allografts used inside contained defects give consistently good results. Frozen grafts seem to incorporate faster and better than lyophilised grafts. (Author)

  11. Predicting internal red oak (Quercus rubra) log defect features using surface defect defect measurements

    R. Edward. Thomas

    2013-01-01

    Determining the defects located within a log is crucial to understanding the tree/log resource for efficient processing. However, existing means of doing this non-destructively requires the use of expensive x-ray/CT (computerized tomography), MRI (magnetic resonance imaging), or microwave technology. These methods do not lend themselves to fast, efficient, and cost-...

  12. Lyophilized allogeneic bone grafts for cystic and discontinuity defects of the jaws

    Pill Hoon Choung; Eun Seok Kim

    1999-01-01

    Allogenic bone grafts have been used after various processing in each institute was made by lyophilized allogenic bone and used for maxillofacial reconstruction. Three types of lyophilized allogenic bone grafts as powder, chip and block form were performed to reconstruct the following defects: 1) maxillectomy, 2) mandiblectomy, 3) cystectomy, 4) cleft alveolus, 5) gap in orthognathic osteotomy, 6) peri-implant defect, 7) extraction socket, and 8) facial contouring. Above defects can be classified as cystic and discontinuity defects of the maxilia and the mandible. Because discontinuity defects have more difficult problems to reconstruct considering mechanical strength of the allogenic bone. We performed allogenic bone grafts on 50 cystic defects and 12 discontinuity defects of the jaws. Among them, 3 cases were removed due to infection, and the others had no complications. In reconstruction of cystic defects, the defects were filled with allogenic chip which were made from allogenic block bone at the surgery, which later were changed to host bone. Three cases of them showed tooth eruption through the allogenic bone grafting site, changing the eruption pathway, which was interrupted by the lesion. in reconstruction of discontinuity defects, usually allogenic bone has been used as a tray, in which PMCB or demineralized bone chips were filled. But we tried to reconstruct this discontinuity defect using allogeneic bone block without inside filling of PMCB different from tray type. We will present the results of allogenic bone grafts using cranial bone, costochondral graft, and the mandible

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

    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.

  14. Progressive obesity alters the steroidogenic response to ovulatory stimulation and increases the abundance of mRNAs stored in the ovulated oocyte.

    Pohlmeier, William E; Xie, Fang; Kurz, Scott G; Lu, Ningxia; Wood, Jennifer R

    2014-08-01

    Obese women who are able to attain pregnancy are at increased risk for early-pregnancy loss due, in part, to reduced oocyte quality. We and others have demonstrated that female Lethal Yellow (LY) mice and female C57BL/6 mice fed a high fat diet (B6-HFD) exhibit phenotypes consistent with human obesity. These studies also showed that zygotes collected from LY and B6-HFD females have reduced developmental competence. The current hypothesis is that LY and B6-HFD females exhibit an abnormal response to gonadotropin stimulation compared to C57BL/6 controls fed normal rodent chow (B6-ND), resulting in the ovulation of oocytes with an altered molecular phenotype which may contribute to its reduced developmental competence. To test this hypothesis, age-matched B6-ND, B6-HFD, and LY females were stimulated with exogenous gonadotropins, then circulating hormone levels and the phenotypes of ovulated oocytes were analyzed. There was no difference in ovulation rate or in the percentage of morphologically abnormal oocytes collected from the oviduct of any females. Progesterone and progesterone/estradiol ratios, however, were increased in B6-HFD and LY compared to B6-ND females 16 hr post-human chorionic gonadotropin treatment. The transcript abundance of several candidate oocyte genes was also increased in B6-HFD- and LY-derived oocytes compared to B6-ND-derived oocytes. These data suggest that increased insulin and leptin levels of obese females elevated circulating progesterone concentrations, altered transcriptional activity during oocyte growth, and/or impaired mechanisms of RNA translation and degradation during oocyte maturation. These changes in mRNA abundance likely contribute to reduced oocyte quality and the subsequent poor embryogenesis associated with obesity. © 2014 Wiley Periodicals, Inc.

  15. Serum levels of insulin-like growth factor binding protein-1 and ovulatory responses to clomiphene citrate in women with polycystic ovarian disease.

    Tiitinen, A E; Laatikainen, T J; Seppälä, M T

    1993-07-01

    To study the serum levels of insulin, insulin-like growth factor I (IGF-I), and insulin-like growth factor binding protein-1 (IGFBP-1) in relation to clomiphene citrate (CC) responsiveness in women with polycystic ovarian disease (PCOD). Prospective. PATIENTS, SETTING: Twenty-three women with PCOD admitted consecutively to the University Infertility Clinic, a tertiary referral center. Blood samples were taken at fasting state and during oral glucose tolerance test (OGTT) for the determination of insulin, IGF-I, and IGFBP-1. A dose of 50 to 200 mg/d CC was given for ovulation induction. With CC treatment, ovulation was achieved in 13 of 23 PCOD patients. The IGFBP-1 concentration was lower in CC nonresponders than in CC responders (20.5 +/- 4.0 ng/mL versus 41.0 +/- 8.5 ng/mL) (P PCOD patients. Lean CC nonresponders (n = 7) had almost threefold lower serum IGFBP-1 levels than lean CC responders (n = 6) (24.0 +/- 3.1 ng/mL versus 61.8 +/- 8.6 ng/mL) (P PCOD patients, the IGFBP-1 levels were low irrespective of CC responsiveness (14.8 +/- 8.0 ng/mL versus 16.7 +/- 7.2 ng/mL). The differences remained during OGTT. The concentrations of IGF-I, insulin, sex hormone-binding globulin, LH, FSH, and androgens showed no significant differences between CC responders and nonresponders. There was an inverse correlation between serum insulin and IGFBP-1 levels in obese PCOD patients, whereas this was not seen in lean patients. In lean PCOD patients, low serum IGFBP-1 concentration is related to CC unresponsiveness by a mechanism unrelated to insulin.

  16. Positron lifetime calculation for defects and defect clusters in graphite

    Onitsuka, T.; Ohkubo, H.; Takenaka, M.; Tsukuda, N.; Kuramoto, E.

    2000-01-01

    Calculations of positron lifetime have been made for vacancy type defects in graphite and compared with experimental results. Defect structures were obtained in a model graphite lattice after including relaxation of whole lattice as determined by the molecular dynamics method, where the interatomic potential given by Pablo Andribet, Dominguez-Vazguez, Mari Carmen Perez-Martin, Alonso, Jimenez-Rodriguez [Nucl. Instrum. and Meth. 115 (1996) 501] was used. For the defect structures obtained via lattice relaxation positron lifetime was calculated under the so-called atomic superposition method. Positron lifetimes 204 and 222 ps were obtained for the graphite matrix and a single vacancy, respectively, which can be compared with the experimental results 208 and 233 ps. For planar vacancy clusters, e.g., vacancy loops, lifetime calculation was also made and indicated that lifetime increases with the number of vacancies in a cluster. This is consistent with the experimental result in the region of higher annealing temperature (above 1200 deg. C), where the increase of positron lifetime is seen, probably corresponding to the clustering of mobile vacancies

  17. Effects of Leading Edge Defect on the Aerodynamic and Flow Characteristics of an S809 Airfoil.

    Wang, Yan; Zheng, Xiaojing; Hu, Ruifeng; Wang, Ping

    Unexpected performance degradation occurs in wind turbine blades due to leading edge defect when suffering from continuous impacts with rain drops, hails, insects, or solid particles during its operation life. To assess this issue, this paper numerically investigates the steady and dynamic stall characteristics of an S809 airfoil with various leading edge defects. More leading edge defect sizes and much closer to practical parameters are investigated in the paper. Numerical computation is conducted using the SST k-ω turbulence model, and the method has been validated by comparison with existed published data. In order to ensure the calculation convergence, the residuals for the continuity equation are set to be less than 10-7 and 10-6 in steady state and dynamic stall cases. The simulations are conducted with the software ANSYS Fluent 13.0. It is found that the characteristics of aerodynamic coefficients and flow fields are sensitive to leading edge defect both in steady and dynamic conditions. For airfoils with the defect thickness of 6%tc, leading edge defect has a relative small influence on the aerodynamics of S809 airfoil. For other investigated defect thicknesses, leading edge defect has much greater influence on the flow field structures, pressure coefficients and aerodynamic characteristics of airfoil at relative small defect lengths. For example, the lift coefficients decrease and drag coefficients increase sharply after the appearance of leading edge defect. However, the aerodynamic characteristics could reach a constant value when the defect length is large enough. The flow field, pressure coefficient distribution and aerodynamic coefficients do not change a lot when the defect lengths reach to 0.5%c,1%c, 2%c and 3%c with defect thicknesses of 6%tc, 12%tc,18%tc and 25%tc, respectively. In addition, the results also show that the critical defect length/thickness ratio is 0.5, beyond which the aerodynamic characteristics nearly remain unchanged. In

  18. Effects of Leading Edge Defect on the Aerodynamic and Flow Characteristics of an S809 Airfoil.

    Yan Wang

    Full Text Available Unexpected performance degradation occurs in wind turbine blades due to leading edge defect when suffering from continuous impacts with rain drops, hails, insects, or solid particles during its operation life. To assess this issue, this paper numerically investigates the steady and dynamic stall characteristics of an S809 airfoil with various leading edge defects. More leading edge defect sizes and much closer to practical parameters are investigated in the paper.Numerical computation is conducted using the SST k-ω turbulence model, and the method has been validated by comparison with existed published data. In order to ensure the calculation convergence, the residuals for the continuity equation are set to be less than 10-7 and 10-6 in steady state and dynamic stall cases. The simulations are conducted with the software ANSYS Fluent 13.0.It is found that the characteristics of aerodynamic coefficients and flow fields are sensitive to leading edge defect both in steady and dynamic conditions. For airfoils with the defect thickness of 6%tc, leading edge defect has a relative small influence on the aerodynamics of S809 airfoil. For other investigated defect thicknesses, leading edge defect has much greater influence on the flow field structures, pressure coefficients and aerodynamic characteristics of airfoil at relative small defect lengths. For example, the lift coefficients decrease and drag coefficients increase sharply after the appearance of leading edge defect. However, the aerodynamic characteristics could reach a constant value when the defect length is large enough. The flow field, pressure coefficient distribution and aerodynamic coefficients do not change a lot when the defect lengths reach to 0.5%c,1%c, 2%c and 3%c with defect thicknesses of 6%tc, 12%tc,18%tc and 25%tc, respectively. In addition, the results also show that the critical defect length/thickness ratio is 0.5, beyond which the aerodynamic characteristics nearly remain

  19. Chitosan-glycerol phosphate/blood implants improve hyaline cartilage repair in ovine microfracture defects.

    Hoemann, Caroline D; Hurtig, Mark; Rossomacha, Evgeny; Sun, Jun; Chevrier, Anik; Shive, Matthew S; Buschmann, Michael D

    2005-12-01

    one hour postoperatively, chitosan-glycerol phosphate/blood clots showed increased adhesion to the walls of the defects as compared with the blood clots in the untreated microfracture defects. After histological processing, all blood clots in the control microfracture defects had been lost, whereas chitosanglycerol phosphate/blood clot adhered to and was partly retained on the surfaces of the defect. At six months, defects that had been treated with chitosan-glycerol phosphate/blood were filled with significantly more hyaline repair tissue (p cartilage repair compared with microfracture alone by increasing the amount of tissue and improving its biochemical composition and cellular organization.

  20. Phosphorus doped and defects engineered graphene for improved electrochemical sensing: synergistic effect of dopants and defects

    Chu, Ke; Wang, Fan; Tian, Ye; Wei, Zhen

    2017-01-01

    Heteroatom-doped graphene materials emerged as promising metal-free catalysts have recently attracted a growing interest in electrochemical sensing applications. However, their catalytic activity and sensing performances still need to be further improved. Herein, we reported the development of unique phosphorus (P)-doped and plasma-etched graphene (denoted as PG-E) as an efficient metal-free electrocatalyst for dopamine (DA) sensing. It was demonstrated that introducing both P-dopants and plasma-engineered defects in graphene could synergistically improve the activity toward electrocatalytic oxidation of DA by increasing the accessible active sites and promoting the electron transport capability. The resulting PG-E modified electrode showed exceptional DA sensing performances with low detection limit, high selectivity and good stability. These results suggested that the synergistic effect of dopants and defects might be an important factor for developing the advanced graphene-based metal-free catalysts for electrochemical sensing.

  1. Charged Semiconductor Defects Structure, Thermodynamics and Diffusion

    Seebauer, Edmund G

    2009-01-01

    The technologically useful properties of a solid often depend upon the types and concentrations of the defects it contains. Not surprisingly, defects in semiconductors have been studied for many years, in many cases with a view towards controlling their behavior through various forms of "defect engineering." For example, in the bulk, charging significantly affects the total concentration of defects that are available to mediate phenomena such as solid-state diffusion. Surface defects play an important role in mediating surface mass transport during high temperature processing steps such as epitaxial film deposition, diffusional smoothing in reflow, and nanostructure formation in memory device fabrication. Charged Semiconductor Defects details the current state of knowledge regarding the properties of the ionized defects that can affect the behavior of advanced transistors, photo-active devices, catalysts, and sensors. Features: Group IV, III-V, and oxide semiconductors; Intrinsic and extrinsic defects; and, P...

  2. Defects and boundary RG flows in ℂ/ℤ{sub d}

    Becker, Melanie; Cabrera, Yaniel [George and Cynthia Mitchell Institute for Fundamental Physics and Astronomy,Texas A& M University,College Station, TX 77843-4242 (United States); Robbins, Daniel [Department of Physics, University at Albany,1400 Washington Ave., Albany, NY 12222 (United States)

    2017-02-01

    We show that topological defects in the language of Landau-Ginzburg models carry information about the RG flow between the non-compact orbifolds ℂ/ℤ{sub d}. We show that such defects correctly implement the bulk-induced RG flow on the boundary.

  3. Automatic classification of blank substrate defects

    Boettiger, Tom; Buck, Peter; Paninjath, Sankaranarayanan; Pereira, Mark; Ronald, Rob; Rost, Dan; Samir, Bhamidipati

    2014-10-01

    Mask preparation stages are crucial in mask manufacturing, since this mask is to later act as a template for considerable number of dies on wafer. Defects on the initial blank substrate, and subsequent cleaned and coated substrates, can have a profound impact on the usability of the finished mask. This emphasizes the need for early and accurate identification of blank substrate defects and the risk they pose to the patterned reticle. While Automatic Defect Classification (ADC) is a well-developed technology for inspection and analysis of defects on patterned wafers and masks in the semiconductors industry, ADC for mask blanks is still in the early stages of adoption and development. Calibre ADC is a powerful analysis tool for fast, accurate, consistent and automatic classification of defects on mask blanks. Accurate, automated classification of mask blanks leads to better usability of blanks by enabling defect avoidance technologies during mask writing. Detailed information on blank defects can help to select appropriate job-decks to be written on the mask by defect avoidance tools [1][4][5]. Smart algorithms separate critical defects from the potentially large number of non-critical defects or false defects detected at various stages during mask blank preparation. Mechanisms used by Calibre ADC to identify and characterize defects include defect location and size, signal polarity (dark, bright) in both transmitted and reflected review images, distinguishing defect signals from background noise in defect images. The Calibre ADC engine then uses a decision tree to translate this information into a defect classification code. Using this automated process improves classification accuracy, repeatability and speed, while avoiding the subjectivity of human judgment compared to the alternative of manual defect classification by trained personnel [2]. This paper focuses on the results from the evaluation of Automatic Defect Classification (ADC) product at MP Mask

  4. Cooperation and Defection in Ghetto

    Kułakowski, Krzysztof

    We consider ghetto as a community of people ruled against their will by an external power. Members of the community feel that their laws are broken. However, attempts to leave ghetto makes their situation worse. We discuss the relation of the ghetto inhabitants to the ruling power in context of their needs, organized according to the Maslow hierarchy. Decisions how to satisfy successive needs are undertaken in cooperation with or defection the ruling power. This issue allows to construct the tree of decisions and to adopt the pruning technique from the game theory. Dynamics of decisions can be described within the formalism of fundamental equations. The result is that the strategy of defection is stabilized by the estimated payoff.

  5. A study of complex defects failing by fatigue, ductile tearing and cleavage

    Bezensek, B.; Ren, Z.; Hancock, J.W.

    2001-01-01

    Defect assessment procedures ensure the structural integrity of plant, which may contain complex defects. The present work addresses complex defects with re-entrant sectors, which develop from the interaction of two co-planar surface breaking defects in fatigue. Experimental studies show rapid fatigue growth and amplified crack driving forces in the re-entrant sector. This leads to the rapid evolution of the complex crack into a bounding semielliptical defect. Experiments involving ductile tearing of cracks with a re-entrant sector show that tearing initiates in the re-entrant sector and that the defect evolves into a bounding semielliptical defect. Cleavage failures of defects with re-entrant sectors indicate the re-characterisation procedure is only conservative after invoking constraint arguments. The study confirms the conservatism inherent in the re-characterisation rules of assessment procedures, such as BS 7910 [1] and ASME Section XI [2] for complex defects extending by fatigue or ductile tearing. A potentially non-conservative situation exists for defects with re-entrant sectors failing by cleavage at small fractions of the limit load.(author)

  6. Various Stone-Wales defects in phagraphene

    Openov, L. A.; Podlivaev, A. I.

    2016-08-01

    Various Stone-Wales defects in phagraphene, which is a graphene allotrope, predicted recently are studied in terms of the nonorthogonal tight-binding model. The energies of the defect formation and the heights of energy barriers preventing the formation and annealing of the defects are found. Corresponding frequency factors in the Arrhenius formula are calculated. The evolution of the defect structure is studied in the real-time mode using the molecular dynamics method.

  7. Iatrogenic Urethral Defect Repairment: A Case Report

    Ulas Fidan

    2013-10-01

    Full Text Available    Iatrogenic urethral defect is a complication that occurs after vaginal surgical procedures. Many surgical methods according to place of defect are described in case of injury of urethra. In this article, we reported the repairment of distal urethral defect with the help of greft taken from labia minor. This defect is made by the excision of the granulation tissue that occurred after chronic paraurethral  gland infection.

  8. Defect relaxation in disordered materials

    Crandell, R.S.

    1989-01-01

    Using an exponential distribution of activation barriers, annealing data for metastable effects in hydrogenated amorphous silicon, a-Si:H, are quantitatively explained. This includes the stretched exponential time dependence of annealing and a Meyer-Neldel rule for the annealing time constant. An exponential distribution of annealing energies arises because defects are frozen in during growth at high temperature. Mechanisms that lead to an exponential distribution of annealing energies are weak bond-breaking and charge trapping

  9. Disc defect classification for optical disc drives

    Helvoirt, van J.; Leenknegt, G.A.L.; Steinbuch, M.; Goossens, H.J.

    2005-01-01

    Optical disc drives are subject to various disturbances and faults. A special type of fault is the so-called disc defect. In this paper we present an approach for disc defect classification. It is based on hierarchical clustering of measured signals that are affected by disc defects. The

  10. Metastable and bistable defects in silicon

    Mukashev, Bulat N; Abdullin, Kh A; Gorelkinskii, Yurii V

    2000-01-01

    Existing data on the properties and structure of metastable and bistable defects in silicon are analyzed. Primary radiation-induced defects (vacancies, self-interstitial atoms, and Frenkel pairs), complexes of oxygen, carbon, hydrogen, and other impurity atoms and defects with negative correlation energy are considered. (reviews of topical problems)

  11. Influence of defects on diamond detection properties

    Tromson, Dominique

    2000-01-01

    This work focuses on the study of the influence of defects on the detection properties of diamond. Devices are fabricated using natural as well as synthetic diamond samples grown using the plasma enhanced chemical vapour deposition (CVD). Optical studies with infrared and Raman spectrometry are used to characterise the material properties as well as thermoluminescence and thermally stimulated current measurements. These thermally stimulated analyses reveal the presence of several trapping levels with emission temperatures below or near room temperature as well as an important level near 550 K. The influence of these defects on the alpha and X-ray detector responses is studied as a function of the initial state of the detectors (thermal treatment, irradiation) and of the measurement conditions (time, temperature). The results show a significant correlation between the charged state of traps, namely filled or empty and the response of the detectors. It appears that filling and emptying the traps respectively enhances the sensitivity and stability of detection devices to be used at room temperature and decreases the detection properties at higher temperature. Localised measurements are also used to study the spatial inhomogeneity of natural and CVD diamond samples from the 2D mapping of the detector responses. Non uniformity are attributed to a non-isotropic distribution of defects in natural diamonds. By comparing the detector responses to the topographical map of CVD samples a correlation appears between grains and grain boundaries with the variation of the detector sensitivity. Devices fabricated for detection applications with CVD samples are presented and namely for the monitoring and profiling of synchrotron beams as well as dose rate measurements in harsh environments. (author) [fr

  12. Exploring the multiverse with topological defects

    Zhang, Jun

    Inflationary cosmology suggests a nontrivial spacetime structure on scales beyond our observable universe, the multiverse. Based on the observation that topological defects and vacuum bubbles can spontaneously nucleate in a de Sitter like inflating space, we explore two different aspects of the multiverse model in this thesis. Hence the main body of this study consists of two parts. In the first part, we investigate domain walls and cosmic strings that may nucleate in the false vacuum. If we live in a bubble universe surrounded by the false vacuum, as suggested by the eternal inflationary multiverse model, the nucleating defects could collide with our bubble universe, and leave potentially observable signals. We investigate different kinds of collisions and their consequences. We suggest such collisions generically result in signals such as radiation and gravitational waves or the defects themselves or a combination of both propagating into our bubble, and therefore provide a new approach to searching for the multiverse. In the second part, we study the fate of domain walls and vacuum bubbles that could nucleate in the slow roll inflation. We show that, depending on their sizes, these objects will form either black holes or wormholes after inflation. We study the spacetime structure of the resulting wormholes. Our analysis indicates the presence of domain walls and vacuum bubbles in the slow roll inflation has significant effects on the global structure of our universe, that is by forming wormholes, it can lead to the picture of a multiverse. We also calculate the mass spectrum of the resulting black holes and wormholes under certain assumptions. We argue that the observation of a population of black holes with such mass spectrum could be considered as evidence of the existence of both inflation and multiverse.

  13. Gastroschisis and associated defects: an international study.

    Mastroiacovo, Pierpaolo

    2007-04-01

    Our objective was to evaluate the frequency and type of malformations associated with gastroschisis in a large pool of international data, to identify malformation patterns, and to evaluate the role of maternal age in non-isolated cases. Case-by-case information from 24 registries, all members of the International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR), were evaluated. After the exclusion of other abdominal wall defects cases were classified as: (a) isolated; (b) recognizable syndrome, chromosomal or not; (c) multiple congenital anomalies (MCA). Our results showed that out of 3,322 total cases 469 non-isolated cases were registered (14.1%): 41 chromosomal syndromes, 24 other syndromes, and 404 MCA. Among MCA four groups of anomalies were most frequent: CNS (4.5%), cardio-vascular (2.5%), limb (2.2%), and kidney anomalies (1.9%). No similar patterns emerged except two patterns resembling limb-body wall complex and OEIS. In both of them the gastroschisis could be however misclassified. Chromosomal trisomies and possibly non-syndromic MCA are associated with an older maternal age more than isolated cases. On consideration of our data and the most valid studies published in the literature, the best estimate of the proportion of gastroschisis associated with major unrelated defects is about 10%, with a few cases associated to recognizable syndromes. Recognized syndromes with gastroschisis seem to be so exceptional that the well documented and validated cases are worth being published as interesting case report. An appropriate case definition in etiological studies should include only isolated gastroschisis after an appropriate definition of isolated and non-isolated cases and a thorough case-by-case review.

  14. Defect-induced transitions in synchronous asymmetric exclusion processes

    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

  15. Extracting software static defect models using data mining

    Ahmed H. Yousef

    2015-03-01

    Full Text Available Large software projects are subject to quality risks of having defective modules that will cause failures during the software execution. Several software repositories contain source code of large projects that are composed of many modules. These software repositories include data for the software metrics of these modules and the defective state of each module. In this paper, a data mining approach is used to show the attributes that predict the defective state of software modules. Software solution architecture is proposed to convert the extracted knowledge into data mining models that can be integrated with the current software project metrics and bugs data in order to enhance the prediction. The results show better prediction capabilities when all the algorithms are combined using weighted votes. When only one individual algorithm is used, Naïve Bayes algorithm has the best results, then the Neural Network and the Decision Trees algorithms.

  16. Atrial septal defect in a Korean wild raccoon dog.

    Yim, Soomi; Choi, Sooyoung; Kim, Jongtaek; Chung, Jin-Young; Park, Inchul

    2017-10-07

    An approximately two-year-old, male 6.1 kg body weight, Korean wild raccoon dog (Nyctereutes procyonoides koreensis) was captured by the wildlife medical rescue center of Kangwon National University. Upon physical examination, the heart rate was 87 beats per min and there were no clinical signs. The hematological, and blood biochemical profiles revealed no remarkable findings; however, thoracic radiographs showed cardiac enlargement, especially in the right atrium. On electrocardiogram, sinus node dysfunction and bradyarrhythmia were revealed. Echocardiography showed a left-to-right shunting atrial septal defect. Based on these findings, this Korean wild raccoon dog was diagnosed with atrial septal defect. This is the rare case report of atrial septal defect in wildlife.

  17. Influence of the geometrical soft effect on the radiographic detection of artificial defects

    Bodson, F.; Launay, J.P.

    1980-11-01

    The influence of the geometrical soft effect on image quality and on the sensitivity to detection of artificial defects has been assessed for radiographies achieved with Ir 192 and Co 60 sources. The results show that the threshold of detectability of defects depends increasingly on the geometrical soft effects as the thickness radiographed becomes greater and that the defects in question are finite. The image quality remains accepable on the whole [fr

  18. Absorption and atom mobility in electric field: point defect role in glasses

    Serruys, Y.; Vigouroux, J.P.

    1986-10-01

    During the surface analysis of dielectric materials, the impinging ionising particles induce point defects localised in the band gap and build an electrical charge. The electric field created by the charged defects modifies the physico-chemical properties of surface and bulk. We show that the fundamental study of defects allows a better understanding of technological phenomena such as dielectric breakdown, fracture and diffusion [fr

  19. Total reflection and cloaking by zero index metamaterials loaded with rectangular dielectric defects

    Wu, Ying

    2013-05-06

    In this work, we investigate wave transmission property through a zero index metamaterial (ZIM) waveguide embedded with rectangular dielectric defects. We show that total reflection and total transmission (cloaking) can be achieved by adjusting the geometric sizes and/or permittivities of the defects. Our work provides another possibility of manipulating wave propagation through ZIM in addition to the widely studied dielectric defects with cylindrical geometries.

  20. Defective Ca2+ channel clustering in axon terminals disturbs excitability in motoneurons in spinal muscular atrophy

    Jablonka, Sibylle; Beck, Marcus; Lechner, Barbara Dorothea; Mayer, Christine; Sendtner, Michael

    2007-01-01

    Proximal spinal muscular atrophy (SMA) is a motoneuron disease for which there is currently no effective treatment. In animal models of SMA, spinal motoneurons exhibit reduced axon elongation and growth cone size. These defects correlate with reduced β-actin messenger RNA and protein levels in distal axons. We show that survival motoneuron gene (Smn)–deficient motoneurons exhibit severe defects in clustering Cav2.2 channels in axonal growth cones. These defects also correlate with a reduced f...

  1. Total reflection and cloaking by zero index metamaterials loaded with rectangular dielectric defects

    Wu, Ying; Li, Jichun

    2013-01-01

    In this work, we investigate wave transmission property through a zero index metamaterial (ZIM) waveguide embedded with rectangular dielectric defects. We show that total reflection and total transmission (cloaking) can be achieved by adjusting the geometric sizes and/or permittivities of the defects. Our work provides another possibility of manipulating wave propagation through ZIM in addition to the widely studied dielectric defects with cylindrical geometries.

  2. Symmetry-forbidden intervalley scattering by atomic defects in monolayer transition-metal dichalcogenides

    Kaasbjerg, Kristen; Martiny, Johannes H. J.; Low, Tony

    2017-01-01

    protectionmechanism against intervalley scattering in monolayer TMDs. The predicteddefectdependent selection rules for intervalley scattering can be verified viaFourier transform scanning tunneling spectroscopy (FT-STS), and provide aunique identification of, e.g., atomic vacancy defects (M vs X). Our findingsare......Intervalley scattering by atomic defects in monolayer transition metaldichalcogenides (TDMs; MX2) presents a serious obstacle for applicationsexploiting their unique valley-contrasting properties. Here, we show that thesymmetry of the atomic defects can give rise to an unconventional...

  3. Developmental defects in zebrafish for classification of EGF pathway inhibitors

    Pruvot, Benoist; Curé, Yoann; Djiotsa, Joachim; Voncken, Audrey; Muller, Marc

    2014-01-01

    One of the major challenges when testing drug candidates targeted at a specific pathway in whole animals is the discrimination between specific effects and unwanted, off-target effects. Here we used the zebrafish to define several developmental defects caused by impairment of Egf signaling, a major pathway of interest in tumor biology. We inactivated Egf signaling by genetically blocking Egf expression or using specific inhibitors of the Egf receptor function. We show that the combined occurrence of defects in cartilage formation, disturbance of blood flow in the trunk and a decrease of myelin basic protein expression represent good indicators for impairment of Egf signaling. Finally, we present a classification of known tyrosine kinase inhibitors according to their specificity for the Egf pathway. In conclusion, we show that developmental indicators can help to discriminate between specific effects on the target pathway from off-target effects in molecularly targeted drug screening experiments in whole animal systems. - Highlights: • We analyze the functions of Egf signaling on zebrafish development. • Genetic blocking of Egf expression causes cartilage, myelin and circulatory defects. • Chemical inhibition of Egf receptor function causes similar defects. • Developmental defects can reveal the specificity of Egf pathway inhibitors

  4. Developmental defects in zebrafish for classification of EGF pathway inhibitors

    Pruvot, Benoist; Curé, Yoann; Djiotsa, Joachim; Voncken, Audrey; Muller, Marc, E-mail: m.muller@ulg.ac.be

    2014-01-15

    One of the major challenges when testing drug candidates targeted at a specific pathway in whole animals is the discrimination between specific effects and unwanted, off-target effects. Here we used the zebrafish to define several developmental defects caused by impairment of Egf signaling, a major pathway of interest in tumor biology. We inactivated Egf signaling by genetically blocking Egf expression or using specific inhibitors of the Egf receptor function. We show that the combined occurrence of defects in cartilage formation, disturbance of blood flow in the trunk and a decrease of myelin basic protein expression represent good indicators for impairment of Egf signaling. Finally, we present a classification of known tyrosine kinase inhibitors according to their specificity for the Egf pathway. In conclusion, we show that developmental indicators can help to discriminate between specific effects on the target pathway from off-target effects in molecularly targeted drug screening experiments in whole animal systems. - Highlights: • We analyze the functions of Egf signaling on zebrafish development. • Genetic blocking of Egf expression causes cartilage, myelin and circulatory defects. • Chemical inhibition of Egf receptor function causes similar defects. • Developmental defects can reveal the specificity of Egf pathway inhibitors.

  5. Oxygen defects in Fe-substituted Tl-system superconductors

    李阳; 曹国辉; 王耘波; 马庆珠; 熊小涛; 陈宁; 马如璋; 郭应焕; 许祝安; 王劲松; 张小俊; 焦正宽; 彭获田; 周思海

    1996-01-01

    For Fe-doped T1-1223 phase,the excess oxygen defects induced by Fe dopants are studied by means of Hall coefficient,thermogravimetric measurements,Mossbauer spectroscopy,and the model calculation of the effective bond valence.The extra oxygen defects have effects on carrier density and microstructure of the superconductors.In the light doping level of Fe (x=0-0.05),the superconducting transition and carrier density have significant corresponding relation--the zero resistance temperature Tco and carrier densities decrease linearly with Fe dopants increasing.The thermogravimetric measurements show that the Fe3+ ions’ substituting for Cu2+ ions can bring the extra oxygen into the lattice to form extra oxygen defects.The calculation of the effective bond valence shows that the decrease of carrier density originates the strongly localized binding of the extra oxygen defects.The distortion of Cu-O layer induced by the extra oxygen defects decreases the superconductive transition temperature.The microstructure

  6. Concurrence of metaphyseal fibrous defect and osteosarcoma

    Kyriakos, M.; Murphy, W.A.

    1981-01-01

    The case of a 15-year-old girl with juxtaposition of a femoral metaphyseal fibrous defect (fibrous cortical defect) and an osteosarcoma is reported. Despite the relatively common occurrence of metaphyseal fibrous defects, their reported association with other bone tumors is exceedingly rare. Only two previous acceptable examples of this association were found. Reports of malignant transformation of metaphyseal fibrous defect were reviewed and rejected because they lacked convincing radiologic or histopathologic evidence of a pre-existent benign fibrous lesion. The finding of a malignant bone tumor in association with a metaphyseal fibrous defect appears to be a chance occurrence. (orig.)

  7. Stone-Wales defects can cause a metal-semiconductor transition in carbon nanotubes depending on their orientation

    Partovi-Azar, P; Namiranian, A

    2012-01-01

    It has been shown that the two different orientations of Stone-Wales (SW) defects, i.e. longitudinal and circumferential SW defects, on carbon nanotubes (CNTs) result in two different electronic structures. Based on density functional theory we have shown that the longitudinal SW defects do not open a bandgap near the Fermi energy, while a relatively small bandgap emerges in tubes with circumferential defects. We argue that the bandgap opening in the presence of circumferential SW defects is a consequence of long-range symmetry breaking which can spread all the way along the tube. Specifically, the distribution of contracted and stretched bond lengths due to the presence of defects, and hopping energies for low-energy electrons, i.e. the 2p z electrons, show two different patterns for the two types of defects. Interplay between the geometric features and the electronic properties of the tubes have also been studied for different defect concentrations. Considering π-orbital charge density, it has also been shown that the deviations of bond lengths from their relaxed length result in different doping for two defect orientations around the defects - electron-rich for a circumferential defect and hole-rich for a longitudinal one. We have also shown that, in the tubes having both types of defects, circumferential defects would dominate and impose their electronic properties. (paper)

  8. Determination of defects in depth (stereoradiography)

    Carvalho, Gilberto

    2000-01-01

    After the identification of an internal defect, by means of the single radiographic process, it can be necessary to determine it's position to evaluate the importance of the service and to specify which side of the weld the piece should be cut in order to reduce the amount of material to be removed and, in a lot, the cost of repair. The single radiography image does not have perspective and can not show the tri-dimensional vision, and so, do not clearly indicate the relative positions of the various parts of the object, in the direction of the vision. Stereoradiography was idealized to overcome that limitation of the standard radiography and it requests the accomplishment of two exposures, separated by the normal interpupillary distance. In the present work, we use this technique in a simulated pore defect, commonly found in the welding processes, and we present the efficiency of the technique. The material employed was SAE 1020 steel, in several thickness pieces, covering the range of thickness that the use Ir-192 source is recommended. (author)

  9. Magnetic signature of surface defects at nanodiamonds

    Vollmers, Nora Jenny; Gerstmann, Uwe; Schmidt, Wolf Gero [Theoretische Physik, Universitaet Paderborn (Germany)

    2011-07-01

    The n-type doping of diamond has been a long-standing issue, which recently gained attention in the context of nanodiamonds. Attempts of doping with nitrogen failed to result in the Electron paramagnetic Resonance (EPR) fingerprints expected from bulk material. Instead, the nanodiamond signals show a much larger deviation from the free-electron g-value and are believed to be related to intrinsic, carbon inherited defects. However, the absence of the bulk-like EPR spectra does not mean that nitrogen is not incorporated at all. The N atoms could be built in predominantly at or at least close to the surfaces yielding EPR spectra, very different from those measured in the bulk. In this work, we elucidate the situation by investigating the magnetic signature of paramagnetic defects in the nanodiamonds. We use the gauge-including projector augmented plane wave (GI-PAW) approach to calculate the hyperfine splittings and the elements of the electronic g-tensor. Taking the C(100) surface as a first model system, a possible contribution of nitrogen is discussed by comparing EPR parameters for different N incorporation depths: Incorporated directly at the surface, N gives rise to surface states similar to intrinsic carbon dangling bond-like states. Otherwise N is able to introduce surface conductivity as demonstrated by calculated effective mass tensors.

  10. A study on the healing process of bone defect-examination of healing stages of bone defect in the irradiated mandibular rim by microradiography and autoradiography

    Shimoyama, Tetsuo

    1980-01-01

    The mandibular rim of 150 female Donryu strain rats was exposed to 2000 rads (B group) or to 3000 rads (C group), and a bone defect of 1 x 1 x 2 mm in size was formed in the madibular rim. Cure process of this bone defect was observed periodically by microradiography and autoradiography using 45 Ca as a tracer, compared with that in the control group (A group, non-irradiated). Irradiated rats having bone defects recovered smoothly. Microradiographic findings of the A group showed that new bone was formed on the surface of the perosteum of the mandible on the 7th days after the irradiation. Bone defects in all rats were repaired completely by the 49th days after the irradiation. Microradiographic findings of the B and C groups showed that new bone was formed on the tongue side surface of the periosteum of the mandible in the early stage after the irradiation. However, after that, osteogenesis became slower, and the edge of bone defects or a part of the mandible became smaller. Bone defects were not repaired and became larger. These findings were more marked in the C group than in the B group. Autoradiographic findings showed marked uptake of 45 Ca into new bone in the A group. Rats of which bone defects were repaired showed the uptake of 45 Ca in accordance with the shape of the mandibular rim. The edge of bone defect of the B and C groups where new bone was not formed was destroyed since the 14th day after the irradiation. There were some cases in which the uptake of 45 Ca into the surface of the periosteum of the mandible near bone defect was observed even when bone defect was enlarged. (Tsunoda, M.)

  11. Areva solutions for management of defective fuel

    Morlaes, I.; Vo Van, V.

    2014-01-01

    Defective fuel management is a major challenge for nuclear operators when all fuel must be long-term managed. This paper describes AREVA solutions for managing defective fuel. Transport AREVA performs shipments of defective fuel in Europe and proposes casks that are licensed for that purpose in Europe and in the USA. The paper presents the transport experience and the new European licensing approach of defective fuel transport. Dry Interim Storage AREVA is implementing the defective fuel storage in the USA, compliant with the Safety Authority's requirements. In Europe, AREVA is developing a new, more long-term oriented storage solution for defective fuel, the best available technology regarding safety requirements. The paper describes these storage solutions. Treatment Various types of defective fuel coming from around the world have been treated in the AREVA La Hague plant. Specific treatment procedures were developed when needed. The paper presents operational elements related to this experience. (authors)

  12. Point defects and atomic transport in crystals

    Lidiard, A.B.

    1981-02-01

    There are two principle aspects to the theory of atomic transport in crystals as caused by the action of point defects, namely (1) the calculation of relevant properties of the point defects (energies and other thermodynamic characteristics of the different possible defects, activation energies and other mobility parameters) and (2) the statistical mechanics of assemblies of defects, both equilibrium and non-equilibrium assemblies. In the five lectures given here both these aspects are touched on. The first two lectures are concerned with the calculation of relevant point defect properties, particularly in ionic crystals. The first lecture is more general, the second is concerned particularly with some recent calculations of the free volumes of formation of defects in various ionic solids; these solve a rather long-standing problem in this area. The remaining three lectures are concerned with the kinetic theory of defects mainly in relaxation, drift and diffusion situations

  13. Strong Coupling between Nanofluidic Transport and Interfacial Chemistry: How Defect Reactivity Controls Liquid-Solid Friction through Hydrogen Bonding.

    Joly, Laurent; Tocci, Gabriele; Merabia, Samy; Michaelides, Angelos

    2016-04-07

    Defects are inevitably present in nanofluidic systems, yet the role they play in nanofluidic transport remains poorly understood. Here, we report ab initio molecular dynamics (AIMD) simulations of the friction of liquid water on defective graphene and boron nitride sheets. We show that water dissociates at certain defects and that these "reactive" defects lead to much larger friction than the "nonreactive" defects at which water molecules remain intact. Furthermore, we find that friction is extremely sensitive to the chemical structure of reactive defects and to the number of hydrogen bonds they can partake in with the liquid. Finally, we discuss how the insight obtained from AIMD can be used to quantify the influence of defects on friction in nanofluidic devices for water treatment and sustainable energy harvesting. Overall, we provide new insight into the role of interfacial chemistry on nanofluidic transport in real, defective systems.

  14. Defects improved photocatalytic ability of TiO2

    Li, Lei; Tian, Hong-Wei; Meng, Fan-Ling; Hu, Xiao-Ying; Zheng, Wei-Tao; Sun, Chang Q.

    2014-01-01

    Highlights: • Defect improves the photocatalytic ability by band gap narrowing and carrier life prolonging. • Atomic undercoordination shortens the local bonds, entraps, and polarizes electrons. • Polarization lowers the local workfunction and lengthens carrier life. • Entrapment and polarization narrows the band gap tuning the wavelength of absorption. - Abstract: Defect generation forms an important means modulating the photocatalytic ability of TiO 2 with mechanisms that remain yet unclear. Here we show that a spectral distillation clarifies the impact of defect on modulating the band gap, electroaffinity, and work function of the substance. Firstly, by analyzing XPS measurements, we calibrated the 2p 3/2 level of 451.47 eV for an isolated Ti atom and its shifts by 2.14 and 6.94 eV, respectively, upon Ti and TiO 2 bulk formation. Spectral difference between the defected and the un-defected TiO 2 skin revealed then that the 2p 3/2 level shifts further from 6.94 to 9.67 eV due to the defect-induced quantum entrapment. This entrapment is associated with an elevation of the upper edges of both the 2p 3/2 and the conduction band by polarization. The shortening and strengthening of bonds between undercoordinated atoms densify and entrap the core electrons, which in turn polarize the dangling bond electrons of defect atoms. The entrapment and polarization mediate thus the band gap, the electroaffinity, the work function, and the photocatalytic ability of TiO 2

  15. Is bone transplantation the gold standard for repair of alveolar bone defects?

    Cassio Eduardo Raposo-Amaral

    2014-01-01

    Full Text Available New strategies to fulfill craniofacial bone defects have gained attention in recent years due to the morbidity of autologous bone graft harvesting. We aimed to evaluate the in vivo efficacy of bone tissue engineering strategy using mesenchymal stem cells associated with two matrices (bovine bone mineral and α-tricalcium phosphate, compared to an autologous bone transfer. A total of 28 adult, male, non-immunosuppressed Wistar rats underwent a critical-sized osseous defect of 5 mm diameter in the alveolar region. Animals were divided into five groups. Group 1 (n = 7 defects were repaired with autogenous bone grafts; Group 2 (n = 5 defects were repaired with bovine bone mineral free of cells; Group 3 (n = 5 defects were repaired with bovine bone mineral loaded with mesenchymal stem cells; Group 4 (n = 5 defects were repaired with α-tricalcium phosphate free of cells; and Group 5 (n = 6 defects were repaired with α-tricalcium phosphate loaded with mesenchymal stem cells. Groups 2–5 were compared to Group 1, the reference group. Healing response was evaluated by histomorphometry and computerized tomography. Histomorphometrically, Group 1 showed 60.27% ± 16.13% of bone in the defect. Groups 2 and 3 showed 23.02% ± 8.6% (p = 0.01 and 38.35% ± 19.59% (p = 0.06 of bone in the defect, respectively. Groups 4 and 5 showed 51.48% ± 11.7% (p = 0.30 and 61.80% ± 2.14% (p = 0.88 of bone in the defect, respectively. Animals whose bone defects were repaired with α-tricalcium phosphate and mesenchymal stem cells presented the highest bone volume filling the defects; both were not statistically different from autogenous bone.

  16. Packing defects into ordered structures

    Bechstein, R.; Kristoffersen, Henrik Høgh; Vilhelmsen, L.B.

    2012-01-01

    . With the help of density functional theory calculations we develop a complete structural model for the entire strand and demonstrate these adstructures to be more stable than an equivalent amount of bulk defects such as Ti interstitials. We argue that strands can form particularly easy on stepped surfaces......We have studied vicinal TiO2(110) surfaces by high-resolution scanning tunneling microscopy and density functional theory calculations. On TiO2 surfaces characterized by a high density of ⟨11̅ 1⟩ steps, scanning tunneling microscopy reveals a high density of oxygen-deficient strandlike adstructures...

  17. Simulation and analysis on ultrasonic testing for the cement grouting defects of the corrugated pipe

    Qingbang, Han; Ling, Chen; Changping, Zhu [Changzhou Key Laboratory of Sensor Networks and Environmental Sensing, College of IOT, Hohai University Changzhou, Jiangsu, 213022 (China)

    2014-02-18

    The defects exist in the cement grouting process of prestressed corrugated pipe may directly impair the bridge safety. In this paper, sound fields propagation in concrete structures with corrugated pipes and the influence of various different defects are simulated and analyzed using finite element method. The simulation results demonstrate a much complex propagation characteristic due to multiple reflection, refraction and scattering, where the scattering signals caused by metal are very strong, while the signals scattered by an air bubble are weaker. The influence of defect both in time and frequency domain are found through deconvolution treatment. In the time domain, the deconvolution signals correspond to larger defect display a larger head wave amplitude and shorter arrive time than those of smaller defects; in the frequency domain, larger defect also shows a stronger amplitude, lower center frequency and lower cutoff frequency.

  18. Simulation and analysis on ultrasonic testing for the cement grouting defects of the corrugated pipe

    Qingbang, Han; Ling, Chen; Changping, Zhu

    2014-01-01

    The defects exist in the cement grouting process of prestressed corrugated pipe may directly impair the bridge safety. In this paper, sound fields propagation in concrete structures with corrugated pipes and the influence of various different defects are simulated and analyzed using finite element method. The simulation results demonstrate a much complex propagation characteristic due to multiple reflection, refraction and scattering, where the scattering signals caused by metal are very strong, while the signals scattered by an air bubble are weaker. The influence of defect both in time and frequency domain are found through deconvolution treatment. In the time domain, the deconvolution signals correspond to larger defect display a larger head wave amplitude and shorter arrive time than those of smaller defects; in the frequency domain, larger defect also shows a stronger amplitude, lower center frequency and lower cutoff frequency

  19. Shallow nitrogen ion implantation: Evolution of chemical state and defect structure in titanium

    Manojkumar, P.A., E-mail: manoj@igcar.gov.in [Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Chirayath, V.A.; Balamurugan, A.K.; Krishna, Nanda Gopala; Ilango, S.; Kamruddin, M.; Amarendra, G.; Tyagi, A.K. [Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Raj, Baldev [National Institute of Advanced Studies, Bangalore 560 012 (India)

    2016-09-15

    Highlights: • Low energy nitrogen ion implantation in titanium was studied. • Chemical and defect states were analyzed using SIMS, XPS and PAS. • SIMS and depth resolved XPS data showed good agreement. • Depth resolved defect and chemical states information were revealed. • Formation of 3 layers of defect states proposed to fit PAS results. - Abstract: Evolution of chemical states and defect structure in titanium during low energy nitrogen ion implantation by Plasma Immersion Ion Implantation (PIII) process is studied. The underlying process of chemical state evolution is investigated using secondary ion mass spectrometry and X-ray photoelectron spectroscopy. The implantation induced defect structure evolution as a function of dose is elucidated using variable energy positron annihilation Doppler broadening spectroscopy (PAS) and the results were corroborated with chemical state. Formation of 3 layers of defect state was modeled to fit PAS results.

  20. Band gap control in a line-defect magnonic crystal waveguide

    Morozova, M. A., E-mail: mamorozovama@yandex.ru; Grishin, S. V.; Sadovnikov, A. V.; Romanenko, D. V.; Sharaevskii, Yu. P.; Nikitov, S. A. [Laboratory ' Metamaterials,' Saratov State University, Astrakhanskaya 83, Saratov 410012 (Russian Federation)

    2015-12-14

    We report on the experimental observation of the spin wave spectrum control in a line-defect magnonic crystal (MC) waveguide. We demonstrate the possibility to control the forbidden frequency band (band gap) for spin waves tuning the line-defect width. In particular, this frequency may be greater or lower than the one of 1D MC waveguide without line-defect. By means of space-resolved Brillouin light scattering technique, we study the localization of magnetization amplitude in the line-defect area. We show that the length of this localization region depends on the line-defect width. These results agree well with theoretical calculations of spin wave spectrum using the proposed model of two coupled magnonic crystal waveguides. The proposed simple geometry of MC with line-defect can be used as a logic and multiplexing block for application in the novel field of magnonic devices.

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

    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.

  2. Point defect thermodynamics and diffusion in Fe3C: A first-principles study

    Chao Jiang; Uberuaga, B.P.; Srinivasan, S.G.

    2008-01-01

    The point defect structure of cementite (Fe 3 C) is investigated using a combination of the statistical mechanical Wagner-Schottky model and first-principles calculations within the generalized gradient approximation. Large 128-atom supercells are employed to obtain fully converged point defect formation energies. The present study unambiguously shows that carbon vacancies and octahedral carbon interstitials are the structural defects in C-depleted and C-rich cementite, respectively. The dominant thermal defects in C-depleted and stoichiometric cementite are found to be carbon Frenkel pairs. In C-rich cementite, however, the primary thermal excitations are strongly temperature-dependent: interbranch, Schottky and Frenkel defects dominate successively with increasing temperature. Using the nudged elastic band technique, the migration barriers of major point defects in cementite are also determined and compared with available experiments in the literature

  3. Study on acoustic emission signals of active defect in pressure piping under hydraulic pressure

    Ai Qiong; Liu Caixue; Wang Yao; He Pan; Song Jian

    2009-01-01

    Experimental investigations of acoustic emission (AE) of active defect in pressure piping with a prefabricated crack under hydraulic pressure tester were conducted. AE signals of fatigue-crack-growth in pressure piping were monitored incessantly in all processes, and all signals recorded were analyzed and processed. The result of signal processing show that the amplitude and energy of acoustic emission signals from defect in pressure pipeline increase gradually with the load time, and thus the active defects in pipeline can be identified; the amplitude, energy and count of acoustic emission signals increase sharply before the defect runs through, and we can forecast the penetrated leakage of pipeline. (authors)

  4. Digital detection system of surface defects for large aperture optical elements

    Fan Yong; Chen Niannian; Gao Lingling; Jia Yuan; Wang Junbo; Cheng Xiaofeng

    2009-01-01

    Based on the light defect images against the dark background in a scattering imaging system, a digital detection system of surface defects for large aperture optical elements has been presented. In the system, the image is segmented by a multi-area self-adaptive threshold segmentation method, then a pixel labeling method based on replacing arrays is adopted to extract defect features quickly, and at last the defects are classified through back-propagation neural networks. Experiment results show that the system can achieve real-time detection and classification. (authors)

  5. Defect generation/passivation by low energy hydrogen implant for silicon solar cells

    Sopori, B.L.; Zhou, T.Q.; Rozgonyi, G.A.

    1990-01-01

    Low energy ion implant is shown to produce defects in silicon. These defects include surface damage, hydrogen agglomeration, formation of platelets with (111) habit plane and decoration of dislocations. Hydrogen also produces an inversion type of surface on boron doped silicon. These effects indicate that a preferred approach for passivation is to incorporate hydrogen from the back side of the cell. A backside H + implant technique is described. The results show that degree of passivation differs for various devices. A comparison of the defect structures of hydrogenated devices indicates that the structure and the distribution of defects in the bulk of the material plays a significant role in determining the degree of passivation

  6. On the performance limiting behavior of defect clusters in commercial silicon solar cells

    Sopori, B.L.; Chen, W.; Jones, K. [National Renewable Energy Lab., Golden, CO (United States); Gee, J. [Sandia National Labs., Albuquerque, NM (United States)

    1998-09-01

    The authors report the observation of defect clusters in high-quality, commercial silicon solar cell substrates. The nature of the defect clusters, their mechanism of formation, and precipitation of metallic impurities at the defect clusters are discussed. This defect configuration influences the device performance in a unique way--by primarily degrading the voltage-related parameters. Network modeling is used to show that, in an N/P junction device, these regions act as shunts that dissipate power generated within the cell.

  7. Defects investigation in neutron irradiated reactor steels by positron annihilation

    Slugen, V.

    2003-01-01

    Positron annihilation spectroscopy (PAS) based on positron lifetime measurements using the Pulsed Low Energy Positron System (PLEPS) was applied to the investigation of defects of irradiated and thermally treated reactor pressure vessel (RPV) steels. PLEPS results showed that the changes in microstructure of the RPV-steel properties caused by neutron irradiation and post-irradiation heat treatment can be well detected. From the lifetime measurements in the near-surface region (20-550 nm) the defect density in Russian types of RPV-steels was calculated using the diffusion trapping model. The post-irradiation heat treatment studies performed on non-irradiated specimens are also presented. (author)

  8. Woven fabric defects detection based on texture classification algorithm

    Ben Salem, Y.; Nasri, S.

    2011-01-01

    In this paper we have compared two famous methods in texture classification to solve the problem of recognition and classification of defects occurring in a textile manufacture. We have compared local binary patterns method with co-occurrence matrix. The classifier used is the support vector machines (SVM). The system has been tested using TILDA database. The results obtained are interesting and show that LBP is a good method for the problems of recognition and classifcation defects, it gives a good running time especially for the real time applications.

  9. Dual-probe spectroscopic fingerprints of defects in graphene

    Settnes, Mikkel; Power, Stephen; Petersen, Dirch Hjorth

    2014-01-01

    (e.g., an extended graphene sheet). Applying this method, we study the transport anisotropies in pristine graphene sheets, and analyze the spectroscopic fingerprints arising from quantum interference around single-site defects, such as vacancies and adatoms. Furthermore, we demonstrate that the dual......-probe setup is a useful tool for characterizing the electronic transport properties of extended defects or designed nanostructures. In particular, we show that nanoscale perforations, or antidots, in a graphene sheet display Fano-type resonances with a strong dependence on the edge geometry of the perforation....

  10. Repair of tracheomalacia with inflammatory defect and mediastinitis.

    Sandu, Kishore; Monnier, Yan; Hurni, Michel; Bernath, Marc-Andre; Monnier, Philippe; Wang, Yabo; Ris, Hans-Beat

    2011-01-01

    We describe a novel repair of an anterior inflammatory tracheal defect with mediastinitis, which occurred after external tracheal suspension of localized intrathoracic tracheomalacia. The malacic tracheal segment of 4-cm length containing the inflammatory tracheal defect was noncircumferentially resected. A temporary endotracheal silicone stent was introduced, and the trachea was closed by a pedicled pectoralis muscle flap reinforced with an embedded rib segment. Retrieval of the stent 5 months postoperatively resulted in a re-epithelialized, persistently stable, noncollapsible tracheal segment that showed the same diameter and configuration as the nonreconstructed part of the trachea. Copyright © 2011 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  11. Transfer-matrix approach for modulated structures with defects

    Kostyrko, T.

    2000-01-01

    We consider scattering of electrons by defects in a periodically modulated, quasi-one-dimensional structure, within a tight-binding model. Combining a transfer matrix method and a Green function method we derive a formula for a Landauer conductance and show its equivalence to the result of Kubo linear response theory. We obtain explicitly unperturbed lattice Green functions from their equations of motion, using the transfer matrices. We apply the presented formalism in computations of the conductance of several multiband modulated structures with defects: (a) carbon nanotubes (b) two-dimensional (2D) superlattice (c) modulated leads with 1D wire in the tunneling regime. (c) 2000 The American Physical Society

  12. A DFT study of Cu nanoparticles adsorbed on defective graphene

    García-Rodríguez, D.E.; Mendoza-Huizar, L.H.; Díaz, C.

    2017-01-01

    Highlights: • Cu_n supported on graphene may be a promising electrode material for DBFC's cells. • Cu_n/graphene interaction is rather local and size independent. • Cu_1_3 anchors strongly to defects in graphene, while keeping its gas-phase properties. - Abstract: Metal nanoparticles adsorbed on graphene are systems of interest for processes relative to catalytic reactions and alternative energy production. Graphene decorated with Cu-nanoparticles, in particular, could be a good alternative material for electrodes in direct borohydride fuel cells. However our knowledge of this system is still very limited. Based on density functional theory, we have analyzed the interaction of Cu_n nanoparticles (n = 4, 5, 6, 7, 13) with pristine and defective-graphene. We have considered two types of defects, a single vacancy (SV), and an extended lineal structural defect (ELSD), formed by heptagon-pentagon pairs. Our analysis has revealed the covalent character of the Cu_n-graphene interaction for pristine- and ELSD-graphene, and a more ionic-like interaction for SV-graphene. Furthermore, our analysis shows that the interaction between the nanoparticles and the graphene is rather local, i.e., only the nanoparticle atoms close to the contact region are involved in the interaction, being the electronic contact region much higher for defective-graphene than for pristine-graphene. Thus, the higher the particle the lower its average electronic and structural distortion.

  13. Defect dynamics and coarsening dynamics in smectic-C films

    Pargellis, A. N.; Finn, P.; Goodby, J. W.; Panizza, P.; Yurke, B.; Cladis, P. E.

    1992-12-01

    We study the dynamics of defects generated in free-standing films of liquid crystals following a thermal quench from the smectic-A phase to the smectic-C phase. The defects are type-1 disclinations, and the strain field between defect pairs is confined to 2π walls. We compare our observations with a phenomenological model that includes dipole coupling of the director field to an external ordering field. This model is able to account for both the observed coalescence dynamics and the observed ordering dynamics. In the absence of an ordering field, our model predicts the defect density ρ to scale with time t as ρ lnρ~t-1. When the dipole coupling of the director field to an external ordering field is included, both the model and experiments show the defect coarsening proceeds as ρ~e-αt with the strain field confined to 2π walls. The external ordering field most likely arises from the director's tendency to align with edge dislocations within the liquid-crystal film.

  14. Talbot effect of the defective grating in deep Fresnel region

    Teng, Shuyun; Wang, Junhong; Zhang, Wei; Cui, Yuwei

    2015-02-01

    Talbot effect of the grating with different defect is studied theoretically and experimentally in this paper. The defects of grating include the loss of the diffraction unit, the dislocation of the diffraction unit and the modulation of the unit separation. The exact diffraction distributions of three kinds of defective gratings are obtained according to the finite-difference time-domain (FDTD) method. The calculation results show the image of the missing or dislocating unit appears at the Talbot distance (as mentioned in K. Patorski Prog. Opt., 27, 1989, pp.1-108). This is the so-called self-repair ability of grating imaging. In addition, some more phenomena are discovered. The loss or the dislocation of diffraction unit causes the diffraction distortion within a certain radial angle. The regular modulation of unit separation changes the original diffraction, but the new periodicity of the diffraction distribution rebuilds. The self-imaging of grating with smaller random modulation still keeps the partial self-repair ability, and yet this characteristic depends on the modulation degree of defective grating. These diffraction phenomena of the defective gratings are explained by use of the diffraction theory of grating. The practical experiment is also performed and the experimental results confirm the theoretic predictions.

  15. A DFT study of Cu nanoparticles adsorbed on defective graphene

    García-Rodríguez, D.E. [Universidad Politécnica de Aguascalientes, Calle Paseo San Gerardo No. 297 Fracc. San Gerardo, 20342 Aguascalientes, Ags. (Mexico); Mendoza-Huizar, L.H. [Universidad Autónoma del Estado de Hidalgo, Área Académica de Química, Ciudad del Conocimiento. Carretera Pachuca-Tulancigo Km. 4.5 Mineral de la Reforma, 42186 Hidalgo (Mexico); Díaz, C., E-mail: cristina.diaz@uam.es [Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049 Madrid (Spain); Institute for Advanced Research in Chemical Science (IAdChem), Universidad Autónoma de Madrid, 28049 Madrid (Spain)

    2017-08-01

    Highlights: • Cu{sub n} supported on graphene may be a promising electrode material for DBFC's cells. • Cu{sub n}/graphene interaction is rather local and size independent. • Cu{sub 13} anchors strongly to defects in graphene, while keeping its gas-phase properties. - Abstract: Metal nanoparticles adsorbed on graphene are systems of interest for processes relative to catalytic reactions and alternative energy production. Graphene decorated with Cu-nanoparticles, in particular, could be a good alternative material for electrodes in direct borohydride fuel cells. However our knowledge of this system is still very limited. Based on density functional theory, we have analyzed the interaction of Cu{sub n} nanoparticles (n = 4, 5, 6, 7, 13) with pristine and defective-graphene. We have considered two types of defects, a single vacancy (SV), and an extended lineal structural defect (ELSD), formed by heptagon-pentagon pairs. Our analysis has revealed the covalent character of the Cu{sub n}-graphene interaction for pristine- and ELSD-graphene, and a more ionic-like interaction for SV-graphene. Furthermore, our analysis shows that the interaction between the nanoparticles and the graphene is rather local, i.e., only the nanoparticle atoms close to the contact region are involved in the interaction, being the electronic contact region much higher for defective-graphene than for pristine-graphene. Thus, the higher the particle the lower its average electronic and structural distortion.

  16. Simulating the production of free defects in irradiated metals

    Heinisch, H.L.

    1995-01-01

    Under cascade-producing irradiation by high energy neutrons or charged particles, only a small fraction of the initially displaced atoms contribute to the population of free defects that are available to migrate throughout the metal and cause microstructural changes. Although, in principle, computer simulations of free defect production could best be done using molecular dynamics, in practice, the wide ranges of time and distance scales involved can be done only by a combination of atomistic models that employ various levels of approximation. An atomic-scale, multi-model approach has been developed that combines molecular dynamics, binary collision models and stochastic annealing simulation. The annealing simulation is utilized in calibrating binary collision simulations to the results of molecular dynamics calculations, as well as to model the subsequent migration of the defects on more macroscopic time and size scales. The annealing simulation and the method of calibrating the multi-model approach are discussed, and the results of simulations of cascades in copper are presented. The temperature dependence of free defect production following simulated annealing of isolated cascades in copper shows a differential in the fractions of free vacancies and interstitial defects escaping from the cascade above stage V. This differential, a consequence of the direct formation of interstitial clusters in cascades and the relative thermal stability of vacancy and interstitial clusters during subsequent annealing, is the basis for the production bias mechanism of void swelling. (orig.)

  17. Electronic transport of bilayer graphene with asymmetry line defects

    Zhao, Xiao-Ming; Wu, Ya-Jie; Chen, Chan; Liang, Ying; Kou, Su-Peng

    2016-11-01

    In this paper, we study the quantum properties of a bilayer graphene with (asymmetry) line defects. The localized states are found around the line defects. Thus, the line defects on one certain layer of the bilayer graphene can lead to an electric transport channel. By adding a bias potential along the direction of the line defects, we calculate the electric conductivity of bilayer graphene with line defects using the Landauer-Büttiker theory, and show that the channel affects the electric conductivity remarkably by comparing the results with those in a perfect bilayer graphene. This one-dimensional line electric channel has the potential to be applied in nanotechnology engineering. Project supported by the National Basic Research Program of China (Grant Nos. 2011CB921803 and 2012CB921704), the National Natural Science Foundation of China (Grant Nos. 11174035, 11474025, 11504285, and 11404090), the Specialized Research Fund for the Doctoral Program of Higher Education, China, the Fundamental Research Funds for the Central Universities, China, the Scientific Research Program Fund of the Shaanxi Provincial Education Department, China (Grant No. 15JK1363), and the Young Talent Fund of University Association for Science and Technology in Shaanxi Province, China.

  18. Self-organized defect strings in two-dimensional crystals.

    Lechner, Wolfgang; Polster, David; Maret, Georg; Keim, Peter; Dellago, Christoph

    2013-12-01

    Using experiments with single-particle resolution and computer simulations we study the collective behavior of multiple vacancies injected into two-dimensional crystals. We find that the defects assemble into linear strings, terminated by dislocations with antiparallel Burgers vectors. We show that these defect strings propagate through the crystal in a succession of rapid one-dimensional gliding and rare rotations. While the rotation rate decreases exponentially with the number of defects in the string, the diffusion constant is constant for large strings. By monitoring the separation of the dislocations at the end points, we measure their effective interactions with high precision beyond their spontaneous formation and annihilation, and we explain the double-well form of the dislocation interaction in terms of continuum elasticity theory.

  19. Algorithm of Defect Segmentation for AFP Based on Prepregs

    CAI Zhiqiang

    2017-04-01

    Full Text Available In order to ensure the performance of the automated fiber placement forming parts, according to the homogeneity of the image of the prepreg surface along the fiber direction, a defect segmentation algorithm which was the combination of gray compensation and substraction algorithm based on image processing technology was proposed. The gray compensation matrix of image was used to compensate the gray image, and the maximum error point of the image matrix was eliminated according to the characteristics that the gray error obeys the normal distribution. The standard image was established, using the allowed deviation coefficient K as a criterion for substraction segmentation. Experiments show that the algorithm has good effect, fast speed in segmenting two kinds of typical laying defect of bubbles or foreign objects, and provides a good theoretical basis to realize automatic laying defect online monitoring.

  20. BUILDING OF EXTENSIVE DIAPHYSIS DEFECTS IN LONG BONES

    A. P. Barabash

    2014-01-01

    Full Text Available The problem of extensive diaphysis bone defect replacement in long bones has been investigated. Treatment results of three patients (one with neoplastic process, two with supparative bone damage are given. The sizes of defects were from 16 to 20 cm. Su pervision terms consisted 1-3 years. There were two defect replacement variants: cellular titanium nickelide alongside with interlocking internal fixation - in 2 patients, and metallic prosthesis of ProSpon company (Czech Republic - in 4 patients. Two patients after segmental resection of limb bone tumours and diaphysis endoprosthesis show positive treatment results. Long-term treatment by different methods in 4 patients with chronic fistulous form of post-traumatic osteomyelitis were unsuccessful.

  1. Ginzburg regime and its effects on topological defect formation

    Bettencourt, Luis M. A.; Antunes, Nuno D.; Zurek, W. H.

    2000-01-01

    The Ginzburg temperature has historically been proposed as the energy scale of formation of topological defects at a second order symmetry breaking phase transition. More recently alternative proposals which compute the time of formation of defects from the critical dynamics of the system have been gaining both theoretical and experimental support. We investigate, using a canonical model for string formation, how these two pictures compare. In particular we show that prolonged exposure of a critical field configuration to the Ginzburg regime results in no substantial suppression of the final density of defects formed. These results eliminate the Ginzburg regime as a possible cause of erasure of vortex lines in the recent 4 He pressure quench experiments. (c) 2000 The American Physical Society

  2. Point defects in cubic boron nitride after neutron irradiation

    Atobe, Kozo; Honda, Makoto; Ide, Munetoshi; Yamaji, Hiromichi; Matsukawa, Tokuo; Fukuoka, Noboru; Okada, Moritami; Nakagawa, Masuo.

    1993-01-01

    The production of point defects induced by reactor neutrons and the thermal behavior of defects in sintered cubic boron nitride are investigated using the optical absorption and electron spin resonance (ESR) methods. A strong structureless absorption over the visible region was observed after fast neutron irradiation to a dose of 5.3 x 10 16 n/cm 2 (E > 0.1 MeV) at 25 K. This specimen also shows an ESR signal with g-value 2.006 ± 0.001, which can be tentatively identified as an electron trapped in a nitrogen vacancy. On examination of the thermal decay of the signal, the activation energy for recovery of the defects was determined to be about 1.79 eV. (author)

  3. Magnetoencephalography signals are influenced by skull defects.

    Lau, S; Flemming, L; Haueisen, J

    2014-08-01

    Magnetoencephalography (MEG) signals had previously been hypothesized to have negligible sensitivity to skull defects. The objective is to experimentally investigate the influence of conducting skull defects on MEG and EEG signals. A miniaturized electric dipole was implanted in vivo into rabbit brains. Simultaneous recording using 64-channel EEG and 16-channel MEG was conducted, first above the intact skull and then above a skull defect. Skull defects were filled with agar gels, which had been formulated to have tissue-like homogeneous conductivities. The dipole was moved beneath the skull defects, and measurements were taken at regularly spaced points. The EEG signal amplitude increased 2-10 times, whereas the MEG signal amplitude reduced by as much as 20%. The EEG signal amplitude deviated more when the source was under the edge of the defect, whereas the MEG signal amplitude deviated more when the source was central under the defect. The change in MEG field-map topography (relative difference measure, RDM(∗)=0.15) was geometrically related to the skull defect edge. MEG and EEG signals can be substantially affected by skull defects. MEG source modeling requires realistic volume conductor head models that incorporate skull defects. Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  4. Dopants and defects in semiconductors

    McCluskey, Matthew D

    2012-01-01

    "The book goes beyond the usual textbook in that it provides more specific examples of real-world defect physics … The book will be most useful for beginning graduate students in materials science. … an easy reading, broad introductory overview of the field …"-Materials Today, July-August 2012"… well written, with clear, lucid explanations …"-Chemistry World"The scientific development towards the method of controllable doping transformed the erratic and not reproducible family of semiconductor materials into the truly wonderful basis of modern microelectronics. This book tells the remarkable success story and I recommend it!"-Hans J. Queisser, Max-Planck-Institute, Stuttgart, Germany"McCluskey and Haller have written an outstanding modern guide to this field that will be useful to newcomers, and also to active researchers who want to broaden their horizons, as a means to learn the capabilities and limitations of the many techniques that are used in semiconductor-defect science."-Professor Michael J....

  5. Contribution of dynamic focusing to ultrasonic defect characterization

    Mahaut, S.

    1997-01-01

    Non destructive testing of vessels of pressurized water reactors uses ultrasonic focused transducers, with spherically shaped emitting surface or requiring an acoustic lens. But a mechanically focused transducer has to be used for a given inspection zone and for a fixed control configuration. The aim of this thesis is to improve ultrasonic defect characterization using adaptive dynamic focusing. Such a technique makes use of a ultrasonic defect characterization using adaptive dynamic focusing. Such a technique makes use of an ultrasonic transducer split into an array of individually controlled elements, allowing to apply delay and amplitude laws, calculated from modeling or experimentally deduced. Acoustical characteristics of the ultrasonic beam in the inspected specimen this can be electronically controlled; refraction angle, depth focusing, beam width. We briefly describe in the first chapter a theoretical modeling of the ultrasonic field radiated through a fluid/solid interface, extended to phase array transducers. This model is based on the integral formulation of Rayleigh, modified to take into account transmission through a fluid/solid (homogeneous and isotropic), of planar or cylindrical shape. In the second chapter an experimental study of this technique, with delay and amplitude laws given from the model, is presented, showing the efficiency of this method to adjust the acoustic performances. In he third chapter, experimental delay laws, extracted from the time distribution of signals received by the array (issued from a preliminary detected reflector), are used to provide an optimal imaging of the defect. This self-focusing procedure shows to adapt to a defect without using theoretical delays. The last chapter is dedicated to different applications devoted to improved defect characterization. The first application uses amplitude distribution received by the array, pointing out geometric characteristics of the reflector, while the second application

  6. Atomistic simulation of the point defects in TaW ordered alloy

    atom method (MAEAM), the formation, migration and activation energies of the point defects for six-kind migration mechanisms in B2-type TaW alloy have been investigated. The results showed that the anti-site defects TaW and WTa were easier to form than Ta and W vacancies owing to their lower formation energies.

  7. Point-Defect Mediated Bonding of Pt Clusters on (5,5) Carbon Nanotubes

    Wang, J. G.; Lv, Y. A.; Li, X. N.

    2009-01-01

    The adhesion of various sizes of Pt clusters on the metallic (5,5) carbon nanotubes (CNTs) with and without the point defect has been investigated by means of density functional theory (DFT). The calculations show that the binding energies of Pt-n (n = 1-6) clusters on the defect free CNTs are mo...

  8. Black hole thermodynamics with conical defects

    Appels, Michael [Centre for Particle Theory, Durham University,South Road, Durham, DH1 3LE (United Kingdom); Gregory, Ruth [Centre for Particle Theory, Durham University,South Road, Durham, DH1 3LE (United Kingdom); Perimeter Institute,31 Caroline Street North, Waterloo, ON, N2L 2Y5 (Canada); Kubiznák, David [Perimeter Institute,31 Caroline Street North, Waterloo, ON, N2L 2Y5 (Canada)

    2017-05-22

    Recently we have shown https://www.doi.org/10.1103/PhysRevLett.117.131303 how to formulate a thermodynamic first law for a single (charged) accelerated black hole in AdS space by fixing the conical deficit angles present in the spacetime. Here we show how to generalise this result, formulating thermodynamics for black holes with varying conical deficits. We derive a new potential for the varying tension defects: the thermodynamic length, both for accelerating and static black holes. We discuss possible physical processes in which the tension of a string ending on a black hole might vary, and also map out the thermodynamic phase space of accelerating black holes and explore their critical phenomena.

  9. Effects of in-cascade defect clustering on near-term defect evolution

    Heinisch, H.L. [Pacific Northwest National Lab., Richland, WA (United States)

    1997-08-01

    The effects of in-cascade defect clustering on the nature of the subsequent defect population are being studied using stochastic annealing simulations applied to cascades generated in molecular dynamics (MD) simulations. The results of the simulations illustrates the strong influence of the defect configuration existing in the primary damage state on subsequent defect evolution. The large differences in mobility and stability of vacancy and interstitial defects and the rapid one-dimensional diffusion of small, glissile interstitial loops produced directly in cascades have been shown to be significant factors affecting the evolution of the defect distribution. In recent work, the effects of initial cluster sizes appear to be extremely important.

  10. Positron annihilation spectroscopy in defects of semiconductors

    Fujinami, Masanori

    2002-01-01

    Interaction of positron and defects, application to research of defects of semiconductor and defects on the surface of semiconductor are explained. Cz (Czochralski)-Si single crystal with 10 18 cm -3 impurity oxygen was introduced defects by electron irradiation and the positron lifetime was measured at 90K after annealing. The defect size and recovery temperature were determined by the lifetime measurement. The distribution of defects in the depth direction is shown by S-E curve. The chemical state analysis is possible by CBS (Coincidence Doppler Broadening) spectra. The application to silicon-implanted (100 keV, 2x10 15 cm -2 ) silicon and oxygen-implanted (180 keV, 2x10 15 cm -2 ) silicon are stated. On the oxygen-implanted silicon, the main product was V2 after implantation, V 6 O 2 at 600degC and V 10 O 6 at 800degC. (S.Y.)

  11. Perception of risk from automobile safety defects.

    Slovic, P; MacGregor, D; Kraus, N N

    1987-10-01

    Descriptions of safety engineering defects of the kind that compel automobile manufacturers to initiate a recall campaign were evaluated by individuals on a set of risk characteristic scales that included overall vehicle riskiness, manufacturer's ability to anticipate the defect, importance for vehicle operation, severity of consequences and likelihood of compliance with a recall notice. A factor analysis of the risk characteristics indicated that judgments could be summarized in terms of two composite scales, one representing the uncontrollability of the damage the safety defect might cause and the other representing the foreseeability of the defect by the manufacturer. Motor vehicle defects were found to be highly diverse in terms of the perceived qualities of their risks. Location of individual defects within the factor space was closely associated with perceived riskiness, perceived likelihood of purchasing another car from the same manufacturer, perceived likelihood of compliance with a recall notice, and actual compliance rates.

  12. Strained interface defects in silicon nanocrystals

    Lee, Benjamin G.; Stradins, Paul [National Center for Photovoltaics, National Renewable Energy Laboratory, Golden, CO (United States); Hiller, Daniel; Zacharias, Margit [IMTEK - Faculty of Engineering, Albert-Ludwigs-University Freiburg (Germany); Luo, Jun-Wei; Beard, Matthew C. [Chemical and Materials Science, National Renewable Energy Laboratory, Golden, CO (United States); Semonin, Octavi E. [Chemical and Materials Science, National Renewable Energy Laboratory, Golden, CO (United States); Department of Physics, University of Colorado, Boulder, CO (United States)

    2012-08-07

    The surface of silicon nanocrystals embedded in an oxide matrix can contain numerous interface defects. These defects strongly affect the nanocrystals' photoluminescence efficiency and optical absorption. Dangling-bond defects are nearly eliminated by H{sub 2} passivation, thus decreasing absorption below the quantum-confined bandgap and enhancing PL efficiency by an order of magnitude. However, there remain numerous other defects seen in absorption by photothermal deflection spectroscopy; these defects cause non-radiative recombination that limits the PL efficiency to <15%. Using atomistic pseudopotential simulations, we attribute these defects to two specific types of distorted bonds: Si-Si and bridging Si-O-Si bonds between two Si atoms at the nanocrystal surface. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Primordial inhomogeneities from massive defects during inflation

    Firouzjahi, Hassan; Karami, Asieh; Rostami, Tahereh, E-mail: firouz@ipm.ir, E-mail: karami@ipm.ir, E-mail: t.rostami@ipm.ir [School of Astronomy, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of)

    2016-10-01

    We consider the imprints of local massive defects, such as a black hole or a massive monopole, during inflation. The massive defect breaks the background homogeneity. We consider the limit that the physical Schwarzschild radius of the defect is much smaller than the inflationary Hubble radius so a perturbative analysis is allowed. The inhomogeneities induced in scalar and gravitational wave power spectrum are calculated. We obtain the amplitudes of dipole, quadrupole and octupole anisotropies in curvature perturbation power spectrum and identify the relative configuration of the defect to CMB sphere in which large observable dipole asymmetry can be generated. We observe a curious reflection symmetry in which the configuration where the defect is inside the CMB comoving sphere has the same inhomogeneous variance as its mirror configuration where the defect is outside the CMB sphere.

  14. Little string origin of surface defects

    Haouzi, Nathan; Schmid, Christian [Center for Theoretical Physics, University of California, Berkeley,LeConte Hall, Berkeley (United States)

    2017-05-16

    We derive a large class of codimension-two defects of 4d N=4 Super Yang-Mills (SYM) theory from the (2,0) little string. The origin of the little string is type IIB theory compactified on an ADE singularity. The defects are D-branes wrapping the 2-cycles of the singularity. We use this construction to make contact with the description of SYM defects due to Gukov and Witten https://arxiv.org/abs/hep-th/0612073. Furthermore, we provide a geometric perspective on the nilpotent orbit classification of codimension-two defects, and the connection to ADE-type Toda CFT. The only data needed to specify the defects is a set of weights of the algebra obeying certain constraints, which we give explicitly. We highlight the differences between the defect classification in the little string theory and its (2,0) CFT limit.

  15. Agricultural Compounds in Water and Birth Defects.

    Brender, Jean D; Weyer, Peter J

    2016-06-01

    Agricultural compounds have been detected in drinking water, some of which are teratogens in animal models. The most commonly detected agricultural compounds in drinking water include nitrate, atrazine, and desethylatrazine. Arsenic can also be an agricultural contaminant, although arsenic often originates from geologic sources. Nitrate has been the most studied agricultural compound in relation to prenatal exposure and birth defects. In several case-control studies published since 2000, women giving birth to babies with neural tube defects, oral clefts, and limb deficiencies were more likely than control mothers to be exposed to higher concentrations of drinking water nitrate during pregnancy. Higher concentrations of atrazine in drinking water have been associated with abdominal defects, gastroschisis, and other defects. Elevated arsenic in drinking water has also been associated with birth defects. Since these compounds often occur as mixtures, it is suggested that future research focus on the impact of mixtures, such as nitrate and atrazine, on birth defects.

  16. Charge transfer of edge states in zigzag silicene nanoribbons with Stone–Wales defects from first-principles

    Ting, Xie [College of Mathematics and Statistics, Chongqing University, Chongqing 401331 (China); School of Mathematics and Statistic, Chongqing University of Technology, Chongqing 400054 (China); Rui, Wang, E-mail: rcwang@cqu.edu.cn [Institute for Structure and Function and Department of Physics, Chongqing University, Chongqing 400044 (China); State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Science, Beijing 100190 (China); Shaofeng, Wang [Institute for Structure and Function and Department of Physics, Chongqing University, Chongqing 400044 (China); Xiaozhi, Wu, E-mail: xiaozhiwu@cqu.edu.cn [Institute for Structure and Function and Department of Physics, Chongqing University, Chongqing 400044 (China)

    2016-10-15

    Highlights: • The properties of SW defects in silicene and ZSNRs are obtained. • The SW defects at the edge of ZSNRs induce a sizable gap. • The charge transfer of edge states is resulted from SW defects in ZSNRS. - Abstract: Stone–Wales (SW) defects are favorably existed in graphene-like materials with honeycomb lattice structure and potentially employed to change the electronic properties in band engineering. In this paper, we investigate structural and electronic properties of SW defects in silicene sheet and its nanoribbons as a function of their concentration using the methods of periodic boundary conditions with first-principles calculations. We first calculate the formation energy, structural properties, and electronic band structures of SW defects in silicene sheet, with dependence on the concentration of SW defects. Our results show a good agreement with available values from the previous first-principles calculations. The energetics, structural aspects, and electronic properties of SW defects with dependence on defect concentration and location in edge-hydrogenated zigzag silicene nanoribbons are obtained. For all calculated concentrations, the SW defects prefer to locate at the edge due to the lower formation energy. The SW defects at the center of silicene nanoribbons slightly influence on the electronic properties, whereas the SW defects at the edge of silicene nanoribbons split the degenerate edge states and induce a sizable gap, which depends on the concentration of defects. It is worth to find that the SW defects produce a perturbation repulsive potential, which leads the decomposed charge of edge states at the side with defect to transfer to the other side without defect.

  17. Phosphorous–vacancy–oxygen defects in silicon

    Wang, Hao

    2013-07-30

    Electronic structure calculations employing the hybrid functional approach are used to gain fundamental insight in the interaction of phosphorous with oxygen interstitials and vacancies in silicon. It recently has been proposed, based on a binding energy analysis, that phosphorous–vacancy–oxygen defects may form. In the present study we investigate the stability of this defect as a function of the Fermi energy for the possible charge states. Spin polarization is found to be essential for the charge neutral defect.

  18. Research In Diagnosing Bearing Defects From Vibrations

    Zoladz, T.; Earhart, E.; Fiorucci, T.

    1995-01-01

    Report describes research in bearing-defect signature analysis - use of vibration-signal analysis to diagnose defects in roller and ball bearings. Experiments performed on bearings in good condition and other bearings in which various parts scratched to provide known defects correlated with vibration signals. Experiments performed on highly instrumented motor-driven rotor assembly at speeds up to 10,050 r/min, using accelerometers, velocity probes, and proximity sensors mounted at various locations on assembly to measure vibrations.

  19. Thermophysical spectroscopy of defect states in silicon

    Igamberdyev, Kh.T.; Mamadalimov, A.T.; Khabibullaev, P.K.

    1989-01-01

    The present work deals with analyzing the possibilities of using the non-traditional thermophysical methods to study a defect structure in silicon. For this purpose, the temperature dependences of thermophysical properties of defect silicon are investigated. A number of new, earlier unknown physical phenomena in silicon are obtained, and their interpretation has enabled one to establish the main physical mechanisms of formation of deep defect states in silicon

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

    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

  1. Renyi entropy and conformal defects

    Bianchi, Lorenzo [Humboldt-Univ. Berlin (Germany). Inst. fuer Physik; Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik; Meineri, Marco [Scuola Normale Superiore, Pisa (Italy); Perimeter Institute for Theoretical Physics, Waterloo, ON (Canada); Istituto Nazionale di Fisica Nucleare, Pisa (Italy); Myers, Robert C. [Perimeter Institute for Theoretical Physics, Waterloo, ON (Canada); Smolkin, Michael [California Univ., Berkely, CA (United States). Center for Theoretical Physics and Department of Physics

    2016-04-18

    We propose a field theoretic framework for calculating the dependence of Renyi entropies on the shape of the entangling surface in a conformal field theory. Our approach rests on regarding the corresponding twist operator as a conformal defect and in particular, we define the displacement operator which implements small local deformations of the entangling surface. We identify a simple constraint between the coefficient defining the two-point function of the displacement operator and the conformal weight of the twist operator, which consolidates a number of distinct conjectures on the shape dependence of the Renyi entropy. As an example, using this approach, we examine a conjecture regarding the universal coefficient associated with a conical singularity in the entangling surface for CFTs in any number of spacetime dimensions. We also provide a general formula for the second order variation of the Renyi entropy arising from small deformations of a spherical entangling surface, extending Mezei's results for the entanglement entropy.

  2. Universe as a topological defect

    Anabalon, Andres; Willison, Steven; Zanelli, Jorge

    2008-01-01

    Four-dimensional Einstein's general relativity is shown to arise from a gauge theory for the conformal group, SO(4,2). The theory is constructed from a topological dimensional reduction of the six-dimensional Euler density integrated over a manifold with a four-dimensional topological defect. The resulting action is a four-dimensional theory defined by a gauged Wess-Zumino-Witten term. An ansatz is found which reduces the full set of field equations to those of Einstein's general relativity. When the same ansatz is replaced in the action, the gauged WZW term reduces to the Einstein-Hilbert action. Furthermore, the unique coupling constant in the action can be shown to take integer values if the fields are allowed to be analytically continued to complex values

  3. Neural Tube Defects and Pregnancy

    Emine Çoşar

    2009-09-01

    Full Text Available OBJECTIVE: Neural tube defects are congenital malformations those mostly causing life-long morbidities. They are prevented by the periconseptional folic acid usage and prenatal diagnostic methods. MATERIALS-METHODS: Pregnants from Afyonkarahisar and neighbourhood cities applied to our hospital and determined NTD, were investigated. RESULTS: In our obstetrics clinic 1403 delivery were made and 43 of them had fetus with NTD. Among these fetuses 41.3% had meningomyelocel, 17.4% had meningocel, 21.7% had encephalocel, 8.7% had unencephali and 4.3% had iniencephali. CONCLUSION: Incidence of NTD is high in our region and geographic region, nutrition and other socioeconomic factors may be related to the high incidence. Education of the mother and periconceptional folic acid usage may reduce teh incidence of NTD.

  4. Renyi entropy and conformal defects

    Bianchi, Lorenzo; Myers, Robert C.; Smolkin, Michael

    2016-01-01

    We propose a field theoretic framework for calculating the dependence of Renyi entropies on the shape of the entangling surface in a conformal field theory. Our approach rests on regarding the corresponding twist operator as a conformal defect and in particular, we define the displacement operator which implements small local deformations of the entangling surface. We identify a simple constraint between the coefficient defining the two-point function of the displacement operator and the conformal weight of the twist operator, which consolidates a number of distinct conjectures on the shape dependence of the Renyi entropy. As an example, using this approach, we examine a conjecture regarding the universal coefficient associated with a conical singularity in the entangling surface for CFTs in any number of spacetime dimensions. We also provide a general formula for the second order variation of the Renyi entropy arising from small deformations of a spherical entangling surface, extending Mezei's results for the entanglement entropy.

  5. Subsurface defects structural evolution in nano-cutting of single crystal copper

    Wang, Quanlong; Bai, Qingshun; Chen, Jiaxuan; Sun, Yazhou; Guo, Yongbo; Liang, Yingchun

    2015-01-01

    Highlights: • An innovative analysis method is adopted to analyze nano-cutting process accurately. • A characteristic SFT and stair-rod dislocation are found in subsurface defect layer. • The formation mechanism of stair-rod dislocation is investigated. • The local atomic structure of subsurface defects is introduced. - Abstract: In this work, molecular dynamics simulation is performed to study the subsurface defects structural distribution and its evolution during nano-cutting process of single crystal copper. The formation mechanism of chip and machined surface is interviewed by analyzing the dislocation evolution and atomic migration. The centro-symmetry parameter and spherical harmonics method are adopted to characterize the distribution and evolution of the subsurface defect structures and local atomic structures. The results show that stacking faults, dislocation loops, “V-shaped” dislocation loops, and plenty of point defects are formed during the machined surface being formed in shear-slip zone. In subsurface damage layers, stair-rod dislocation, stacking fault tetrahedra, atomic cluster defect, and vacancy defect are formed. And the formation mechanism of stair-rod dislocation is investigated by atomic-scale structure evolution. The local atomic structures of subsurface defects are icosahedrons, hexagonal close packed, body-centered cubic, and defect face center cubic, and the variations of local atomic structures are investigated

  6. Subsurface defects structural evolution in nano-cutting of single crystal copper

    Wang, Quanlong [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China); Center for Precision Engineering, Harbin Institute of Technology, Harbin 150001 (China); Bai, Qingshun [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China); Chen, Jiaxuan, E-mail: wangquanlong0@hit.edu.cn [Center for Precision Engineering, Harbin Institute of Technology, Harbin 150001 (China); Sun, Yazhou [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China); Guo, Yongbo [Center for Precision Engineering, Harbin Institute of Technology, Harbin 150001 (China); Liang, Yingchun [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2015-07-30

    Highlights: • An innovative analysis method is adopted to analyze nano-cutting process accurately. • A characteristic SFT and stair-rod dislocation are found in subsurface defect layer. • The formation mechanism of stair-rod dislocation is investigated. • The local atomic structure of subsurface defects is introduced. - Abstract: In this work, molecular dynamics simulation is performed to study the subsurface defects structural distribution and its evolution during nano-cutting process of single crystal copper. The formation mechanism of chip and machined surface is interviewed by analyzing the dislocation evolution and atomic migration. The centro-symmetry parameter and spherical harmonics method are adopted to characterize the distribution and evolution of the subsurface defect structures and local atomic structures. The results show that stacking faults, dislocation loops, “V-shaped” dislocation loops, and plenty of point defects are formed during the machined surface being formed in shear-slip zone. In subsurface damage layers, stair-rod dislocation, stacking fault tetrahedra, atomic cluster defect, and vacancy defect are formed. And the formation mechanism of stair-rod dislocation is investigated by atomic-scale structure evolution. The local atomic structures of subsurface defects are icosahedrons, hexagonal close packed, body-centered cubic, and defect face center cubic, and the variations of local atomic structures are investigated.

  7. Effect of synthetic cell-binding peptide on the healing of cortical segmental bone defects

    Cakmak, G.; Bolukbasi, S.; Simsek, A.; Senkoylu, A.; Erdem, O.; Yilmaz, G.

    2006-01-01

    To determine the effect of inorganic bone matric/Pepgen P-15 (ABM/P-15) on the healing of a critical sized segmental defect in a rat radius using a radiological and histological grading system. We carried out this study at the Research Laboratories, Gazi University School of Medicine in 2004. Critical sized segmental defects were created in the radius of 36 Wistar rats. Thirteen defects were filled with ABM/P-15 Flow (gel form), 12 defects were filled with ABM/P-15, and 11 defects were used as a control group. The rats were sacrified at the tenth week, and healing of the defects was evaluated radiographically and histologically. The usage of ABM/P-15 and ABM/P-15 Flow were demonstrated to improve healing of segmental bone defects compared with the control group. Statistical evaluation showed that there were significant differences between control sites, and the sites treated with P-15 and P-15 Flow (p=0.011). The highest radiological and histological grades were achieved by P-15. Segmental cortical bone defects may be treated with ABM/P-15 instead of bone allografts, and autografts. According to the radiological and histological parameters measured in this study, the implantation of ABM/P-15 resulted in optimum healing of the segmental cortical bone defects. Pepgen P-15 has a positive effect on bone healing, without any immunogenic features and disease transmission risk. Therefore, ABM/P-15 can also be used for orthopedic surgery. (author)

  8. Influence of point defects on the near edge structure of hexagonal boron nitride

    McDougall, Nicholas L.; Partridge, Jim G.; Nicholls, Rebecca J.; Russo, Salvy P.; McCulloch, Dougal G.

    2017-10-01

    Hexagonal boron nitride (hBN) is a wide-band-gap semiconductor with applications including gate insulation layers in graphene transistors, far-ultraviolet light emitting devices and as hydrogen storage media. Due to its complex microstructure, defects in hBN are challenging to identify. Here, we combine x-ray absorption near edge structure (XANES) spectroscopy with ab initio theoretical modeling to identify energetically favorable defects. Following annealing of hBN samples in vacuum and oxygen, the B and N K edges exhibited angular-dependent peak modifications consistent with in-plane defects. Theoretical calculations showed that the energetically favorable defects all produce signature features in XANES. Comparing these calculations with experiments, the principle defects were attributed to substitutional oxygen at the nitrogen site, substitutional carbon at the boron site, and hydrogen passivated boron vacancies. Hydrogen passivation of defects was found to significantly affect the formation energies, electronic states, and XANES. In the B K edge, multiple peaks above the major 1 s to π* peak occur as a result of these defects and the hydrogen passivated boron vacancy produces the frequently observed doublet in the 1 s to σ* transition. While the N K edge is less sensitive to defects, features attributable to substitutional C at the B site were observed. This defect was also calculated to have mid-gap states in its band structure that may be responsible for the 4.1-eV ultraviolet emission frequently observed from this material.

  9. Mechanical properties and fracture behaviour of defective phosphorene nanotubes under uniaxial tension

    Liu, Ping; Pei, Qing-Xiang; Huang, Wei; Zhang, Yong-Wei

    2017-12-01

    The easy formation of vacancy defects and the asymmetry in the two sublayers of phosphorene nanotubes (PNTs) may result in brand new mechanical properties and failure behaviour. Herein, we investigate the mechanical properties and fracture behaviour of defective PNTs under uniaxial tension using molecular dynamics simulations. Our simulation results show that atomic vacancies cause local stress concentration and thus significantly reduce the fracture strength and fracture strain of PNTs. More specifically, a 1% defect concentration is able to reduce the fracture strength and fracture strain by as much as 50% and 66%, respectively. Interestingly, the reduction in the mechanical properties is found to depend on the defect location: a defect located in the outer sublayer has a stronger effect than one located in the inner layer, especially for PNTs with a small diameter. Temperature is also found to strongly influence the mechanical properties of both defect-free and defective PNTs. When the temperature is increased from 0 K to 400 K, the fracture strength and fracture strain of defective PNTs with a defect concentration of 1% are reduced further by 71% and 61%, respectively. These findings are of great importance for the structural design of PNTs as building blocks in nanodevices.

  10. Topological defects control collective dynamics in neural progenitor cell cultures

    Kawaguchi, Kyogo; Kageyama, Ryoichiro; Sano, Masaki

    2017-04-01

    Cultured stem cells have become a standard platform not only for regenerative medicine and developmental biology but also for biophysical studies. Yet, the characterization of cultured stem cells at the level of morphology and of the macroscopic patterns resulting from cell-to-cell interactions remains largely qualitative. Here we report on the collective dynamics of cultured murine neural progenitor cells (NPCs), which are multipotent stem cells that give rise to cells in the central nervous system. At low densities, NPCs moved randomly in an amoeba-like fashion. However, NPCs at high density elongated and aligned their shapes with one another, gliding at relatively high velocities. Although the direction of motion of individual cells reversed stochastically along the axes of alignment, the cells were capable of forming an aligned pattern up to length scales similar to that of the migratory stream observed in the adult brain. The two-dimensional order of alignment within the culture showed a liquid-crystalline pattern containing interspersed topological defects with winding numbers of +1/2 and -1/2 (half-integer due to the nematic feature that arises from the head-tail symmetry of cell-to-cell interaction). We identified rapid cell accumulation at +1/2 defects and the formation of three-dimensional mounds. Imaging at the single-cell level around the defects allowed us to quantify the velocity field and the evolving cell density; cells not only concentrate at +1/2 defects, but also escape from -1/2 defects. We propose a generic mechanism for the instability in cell density around the defects that arises from the interplay between the anisotropic friction and the active force field.

  11. Improving reticle defect disposition via fully automated lithography simulation

    Mann, Raunak; Goodman, Eliot; Lao, Keith; Ha, Steven; Vacca, Anthony; Fiekowsky, Peter; Fiekowsky, Dan

    2016-03-01

    Most advanced wafer fabs have embraced complex pattern decoration, which creates numerous challenges during in-fab reticle qualification. These optical proximity correction (OPC) techniques create assist features that tend to be very close in size and shape to the main patterns as seen in Figure 1. A small defect on an assist feature will most likely have little or no impact on the fidelity of the wafer image, whereas the same defect on a main feature could significantly decrease device functionality. In order to properly disposition these defects, reticle inspection technicians need an efficient method that automatically separates main from assist features and predicts the resulting defect impact on the wafer image. Analysis System (ADAS) defect simulation system[1]. Up until now, using ADAS simulation was limited to engineers due to the complexity of the settings that need to be manually entered in order to create an accurate result. A single error in entering one of these values can cause erroneous results, therefore full automation is necessary. In this study, we propose a new method where all needed simulation parameters are automatically loaded into ADAS. This is accomplished in two parts. First we have created a scanner parameter database that is automatically identified from mask product and level names. Second, we automatically determine the appropriate simulation printability threshold by using a new reference image (provided by the inspection tool) that contains a known measured value of the reticle critical dimension (CD). This new method automatically loads the correct scanner conditions, sets the appropriate simulation threshold, and automatically measures the percentage of CD change caused by the defect. This streamlines qualification and reduces the number of reticles being put on hold, waiting for engineer review. We also present data showing the consistency and reliability of the new method, along with the impact on the efficiency of in

  12. Repair of a mandibular defect with a free vascularized coccygeal vertebra transfer in a dog.

    Yeh, L S; Hou, S M

    1994-01-01

    Bilateral mandibular defects in a male mongrel dog were repaired. On the left side, a free vascularized coccygeal bone graft that included the median caudal artery and caudal vein was used to correct the defect. On the right side, the defect was bridged with a bone plate and screws. For further immobilization, the muzzle was temporarily taped for 3 weeks and a pharyngostomy tube was used for nutritional support. The dog was able to eat dry commercial food satisfactorily within 2 months of surgery despite mild malocclusion. Radiographs taken 2 months and 18 months postoperatively showed bony union with graft hypertrophy in the left mandible, whereas the right mandibular defect showed protracted nonunion. The results indicate that vascularized coccygeal vertebra transfer provides an alternative for the management of canine mandibular defects.

  13. Investigation on the effect of atomic defects on the breaking behaviors of gold nanowires

    Wang Fenying; Sun Wei; Wang Hongbo; Zhao Jianwei; Kiguchi, Manabu; Sun Changqing

    2012-01-01

    The mechanical properties and breaking behaviors of the [100]-oriented single-crystal gold nanowires containing a set of defect ratios have been studied at different temperatures using molecular dynamics simulations. The size of the nanowire is 10a × 10a × 30a (a stands for lattice constant, 0.408 nm for gold). The mechanical strengths of the nanowires decrease with the increasing temperature. However, the defects that enhance the local thermal energy have improved the nanowire mechanical strength under a wide range of temperature. Comparing to the single-crystal nanowire, the existence of the atomic defects extends the elastic deformation showing a larger yield strain. By summarizing 300 samples at each temperature, the statistical breaking position distribution shows that the nanowire breaking behavior is sensitive to the atomic defects when the defect ratio is 5 % at 100 K, whereas the ratio is 1 % when temperatures are 300 and 500 K.

  14. A magnetically tunable non-Bragg defect mode in a corrugated waveguide filled with liquid crystals

    Zhang, Lu; Fan, Ya-Xian; Liu, Huan; Han, Xu; Lu, Wen-Qiang; Tao, Zhi-Yong

    2018-04-01

    A magnetically tunable, non-Bragg defect mode (NBDM) was created in the terahertz frequency range by inserting a defect in the middle of a periodically corrugated waveguide filled with liquid crystals (LCs). In the periodic waveguide, non-Bragg gaps beyond the Bragg ones, which appear in the transmission spectra, are created by different transverse mode resonances. The transmission spectra of the waveguide containing a defect showed that a defect mode was present inside the non-Bragg gap. The NBDM has quite different features compared to the Bragg defect mode, which includes more complex, high-order guided wave modes. In our study, we filled the corrugated waveguide with LCs to realize the tunability of the NBDM. The simulated results showed that the NBDM in a corrugated waveguide filled with LCs can be used in filters, sensors, switches, and other terahertz integrated devices.

  15. Enhanced defects recombination in ion irradiated SiC

    Izzo, G.; Litrico, G.; Grassia, F.; Calcagno, L.; Foti, G.

    2010-01-01

    Point defects induced in SiC by ion irradiation show a recombination at temperatures as low as 320 K and this process is enhanced after running current density ranging from 80 to 120 A/cm 2 . Ion irradiation induces in SiC the formation of different defect levels and low-temperature annealing changes their concentration. Some levels (S 0 , S x and S 2 ) show a recombination and simultaneously a new level (S 1 ) is formed. An enhanced recombination of defects is besides observed after running current in the diode at room temperature. The carriers introduction reduces the S 2 trap concentration, while the remaining levels are not modified. The recombination is negligible up to a current density of 50 A/cm 2 and increases at higher current density. The enhanced recombination of the S 2 trap occurs at 300 K, which otherwise requires a 400 K annealing temperature. The process can be related to the electron-hole recombination at the associated defect.

  16. Strengthening of defected beam–column joints using CFRP

    Mohamed H. Mahmoud

    2014-01-01

    Full Text Available This paper presents an experimental study for the structural performance of reinforced concrete (RC exterior beam–column joints rehabilitated using carbon-fiber-reinforced polymer (CFRP. The present experimental program consists of testing 10 half-scale specimens divided into three groups covering three possible defects in addition to an adequately detailed control specimen. The considered defects include the absence of the transverse reinforcement within the joint core, insufficient bond length for the beam main reinforcement and inadequate spliced implanted column on the joint. Three different strengthening schemes were used to rehabilitate the defected beam–column joints including externally bonded CFRP strips and sheets in addition to near surface mounted (NSM CFRP strips. The failure criteria including ultimate capacity, mode of failure, initial stiffness, ductility and the developed ultimate strain in the reinforcing steel and CFRP were considered and compared for each group for the control and the CFRP-strengthened specimens. The test results showed that the proposed CFRP strengthening configurations represented the best choice for strengthening the first two defects from the viewpoint of the studied failure criteria. On the other hand, the results of the third group showed that strengthening the joint using NSM strip technique enabled the specimen to outperform the structural performance of the control specimen while strengthening the joints using externally bonded CFRP strips and sheets failed to restore the strengthened joints capacity.

  17. Strengthening of defected beam-column joints using CFRP.

    Mahmoud, Mohamed H; Afefy, Hamdy M; Kassem, Nesreen M; Fawzy, Tarek M

    2014-01-01

    This paper presents an experimental study for the structural performance of reinforced concrete (RC) exterior beam-column joints rehabilitated using carbon-fiber-reinforced polymer (CFRP). The present experimental program consists of testing 10 half-scale specimens divided into three groups covering three possible defects in addition to an adequately detailed control specimen. The considered defects include the absence of the transverse reinforcement within the joint core, insufficient bond length for the beam main reinforcement and inadequate spliced implanted column on the joint. Three different strengthening schemes were used to rehabilitate the defected beam-column joints including externally bonded CFRP strips and sheets in addition to near surface mounted (NSM) CFRP strips. The failure criteria including ultimate capacity, mode of failure, initial stiffness, ductility and the developed ultimate strain in the reinforcing steel and CFRP were considered and compared for each group for the control and the CFRP-strengthened specimens. The test results showed that the proposed CFRP strengthening configurations represented the best choice for strengthening the first two defects from the viewpoint of the studied failure criteria. On the other hand, the results of the third group showed that strengthening the joint using NSM strip technique enabled the specimen to outperform the structural performance of the control specimen while strengthening the joints using externally bonded CFRP strips and sheets failed to restore the strengthened joints capacity.

  18. Scaling defect decay and the reionization history of the Universe

    Avelino, P.P.; Barbosa, D.

    2004-01-01

    We consider a model for the reionization history of the Universe in which a significant fraction of the observed optical depth is a result of direct reionization by the decay products of a scaling cosmic defect network. We show that such network can make a significant contribution to the reionization history of the Universe even if its energy density is very small (the defect energy density has to be greater than about 10 -11 of the background density). We compute the Cosmic Microwave Background temperature, polarization and temperature-polarization cross power spectrum and show that a contribution to the observed optical depth due to the decay products of a scaling defect network may help to reconcile a high optical depth with a low redshift of complete reionization suggested by quasar data. However, if the energy density of defects is approximately a constant fraction of the background density then these models do not explain the large scale bump in the temperature-polarization cross power spectrum observed by Wilkinson Microwave Anisotropy Probe

  19. Paternal occupation and birth defects: findings from the National Birth Defects Prevention Study.

    Desrosiers, T.A.; Herring, A.H.; Shapira, S.K.; Hooiveld, M.; Luben, T.J.; Herdt-Losavio, M.L.; Lin, S.; Olshan, A.F.

    2012-01-01

    Objectives: Several epidemiological studies have suggested that certain paternal occupations may be associated with an increased prevalence of birth defects in offspring. Using data from the National Birth Defects Prevention Study, the authors investigated the association between paternal occupation

  20. Defining defect specifications to optimize photomask production and requalification

    Fiekowsky, Peter

    2006-10-01

    Reducing defect repairs and accelerating defect analysis is becoming more important as the total cost of defect repairs on advanced masks increases. Photomask defect specs based on printability, as measured on AIMS microscopes has been used for years, but the fundamental defect spec is still the defect size, as measured on the photomask, requiring the repair of many unprintable defects. ADAS, the Automated Defect Analysis System from AVI is now available in most advanced mask shops. It makes the use of pure printability specs, or "Optimal Defect Specs" practical. This software uses advanced algorithms to eliminate false defects caused by approximations in the inspection algorithm, classify each defect, simulate each defect and disposition each defect based on its printability and location. This paper defines "optimal defect specs", explains why they are now practical and economic, gives a method of determining them and provides accuracy data.

  1. Modeling the relationships among internal defect features and external Appalachian hardwood log defect indicators

    R. Edward. Thomas

    2009-01-01

    As a hardwood tree grows and develops, surface defects such as branch stubs and wounds are overgrown. Evidence of these defects remain on the log surface for decades and in many instances for the life of the tree. As the tree grows the defect is encapsulated or grown over by new wood. During this process the appearance of the defect in the tree's bark changes. The...

  2. Reduction of Defects in Germanium-Silicon

    2003-01-01

    Crystals grown without contact with a container have far superior quality to otherwise similar crystals grown in direct contact with a container. In addition to float-zone processing, detached- Bridgman growth is a promising tool to improve crystal quality, without the limitations of float zoning or the defects introduced by normal Bridgman growth. Goals of this project include the development of the detached Bridgman process to be reproducible and well understood and to quantitatively compare the defect and impurity levels in crystals grown by these three methods. Germanium (Ge) and germanium-silicon (Ge-Si) alloys are being used. At MSFC, we are responsible for the detached Bridgman experiments intended to differentiate among proposed mechanisms of detachment, and to confirm or refine our understanding of detachment. Because the contact angle is critical to determining the conditions for detachment, the sessile drop method was used to measure the contact angles as a function of temperature and composition for a large number of substrates made of potential ampoule materials. Growth experiments have used pyrolytic boron nitride (pBN) and fused silica ampoules with the majority of the detached results occurring predictably in the pBN. Etch pit density (EPD) measurements of normal and detached Bridgman-grown Ge samples show a two order of magnitude improvement in the detached-grown samples. The nature and extent of detachment is determined by using profilometry in conjunction with optical and electron microscopy. The stability of detachment has been analyzed, and an empirical model for the conditions necessary to achieve sufficient stability to maintain detached growth for extended periods has been developed. We have investigated the effects on detachment of ampoule material, pressure difference above and below the melt, and Si concentration; samples that are nearly completely detached can be grown repeatedly in pBN. Current work is concentrated on developing a

  3. Defects and properties of cadmium oxide based transparent conductors

    Yu, Kin Man, E-mail: kinmanyu@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Kowloon (Hong Kong); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Detert, D. M.; Dubon, O. D. [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States); Chen, Guibin [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Physics Department and Jiangsu Key Laboratory for Chemistry of Low Dimensional Materials, Huaiyin Normal University, Jiangsu 223300 (China); Zhu, Wei [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Physics and The Center for Physical Experiments, University of Science and Technology of China, Hefei, Anhui 230026 (China); Liu, Chaoping [Department of Physics and Materials Science, City University of Hong Kong, Kowloon (Hong Kong); Grankowska, S. [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Institute of Experimental Physics (IEP UW), Warsaw University, Warsaw (Poland); Hsu, L. [Department of Postsecondary Teaching and Learning, University of Minnesota, Minneapolis, Minnesota 55455 (United States); Walukiewicz, Wladek [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2016-05-14

    Transparent conductors play an increasingly important role in a number of semiconductor technologies. This paper reports on the defects and properties of Cadmium Oxide, a transparent conducting oxide which can be potentially used for full spectrum photovoltaics. We carried out a systematic investigation on the effects of defects in CdO thin films undoped and intentionally doped with In and Ga under different deposition and annealing conditions. We found that at low growth temperatures (<200 °C), sputter deposition tends to trap both oxygen vacancies and compensating defects in the CdO film resulting in materials with high electron concentration of ∼2 × 10{sup 20}/cm{sup 3} and mobility in the range of 40–100 cm{sup 2}/V s. Thermal annealing experiments in different ambients revealed that the dominating defects in sputtered CdO films are oxygen vacancies. Oxygen rich CdO films grown by sputtering with increasing O{sub 2} partial pressure in the sputter gas mixture results in films with resistivity from ∼4 × 10{sup −4} to >1 Ω cm due to incorporation of excess O in the form of O-related acceptor defects, likely to be O interstitials. Intentional doping with In and Ga donors leads to an increase of both the electron concentration and the mobility. With proper doping CdO films with electron concentration of more than 10{sup 21 }cm{sup −3} and electron mobility higher than 120 cm{sup 2}/V s can be achieved. Thermal annealing of doped CdO films in N{sub 2} ambient can further improve the electrical properties by removing native acceptors and improving film crystallinity. Furthermore, the unique doping behavior and electrical properties of CdO were explored via simulations based on the amphoteric defect model. A comparison of the calculations and experimental results show that the formation energy of native donors and acceptors at the Fermi stabilization energy is ∼1 eV and that the mobility of sputtered deposited CdO is limited

  4. Defects and properties of cadmium oxide based transparent conductors

    Yu, Kin Man; Detert, D. M.; Dubon, O. D.; Chen, Guibin; Zhu, Wei; Liu, Chaoping; Grankowska, S.; Hsu, L.; Walukiewicz, Wladek

    2016-01-01

    Transparent conductors play an increasingly important role in a number of semiconductor technologies. This paper reports on the defects and properties of Cadmium Oxide, a transparent conducting oxide which can be potentially used for full spectrum photovoltaics. We carried out a systematic investigation on the effects of defects in CdO thin films undoped and intentionally doped with In and Ga under different deposition and annealing conditions. We found that at low growth temperatures (<200 °C), sputter deposition tends to trap both oxygen vacancies and compensating defects in the CdO film resulting in materials with high electron concentration of ∼2 × 10 20 /cm 3 and mobility in the range of 40–100 cm 2 /V s. Thermal annealing experiments in different ambients revealed that the dominating defects in sputtered CdO films are oxygen vacancies. Oxygen rich CdO films grown by sputtering with increasing O 2 partial pressure in the sputter gas mixture results in films with resistivity from ∼4 × 10 −4 to >1 Ω cm due to incorporation of excess O in the form of O-related acceptor defects, likely to be O interstitials. Intentional doping with In and Ga donors leads to an increase of both the electron concentration and the mobility. With proper doping CdO films with electron concentration of more than 10 21  cm −3 and electron mobility higher than 120 cm 2 /V s can be achieved. Thermal annealing of doped CdO films in N 2 ambient can further improve the electrical properties by removing native acceptors and improving film crystallinity. Furthermore, the unique doping behavior and electrical properties of CdO were explored via simulations based on the amphoteric defect model. A comparison of the calculations and experimental results show that the formation energy of native donors and acceptors at the Fermi stabilization energy is ∼1 eV and that the mobility of sputtered deposited CdO is limited by a background acceptor concentration of

  5. Direct Observation of Radiation Defects: Experiment and Interpretation

    Dudarev, S.L.

    2012-01-01

    at low cost in comparison with the mock-up tests, offer scientific insight and make it possible to perform, in combination with experimental information derived from fission and ion-beam irradiation experiments, the preliminary assessment of power plant operating scenarios. Defining the limits of visibility of small defect clusters and dislocation loops, and optimal diffraction conditions for electron microscope imaging, remains one of the central problems of electron microscopy of irradiated materials. Using computer image simulations based on the propagation- interpolation algorithm for solving the Howie-Basinski equations, it is possible to investigate the relation between the actual and the 'observed' size of small loops, the part played by many-beam dynamical diffraction effects, and limitations of electron microscope imaging in identifying the structure of small defects. A particularly impressive and useful application of electron microscopy is given by recent in situ electron microscope observations, providing real-time visualization of dynamics of defects produced by ultra-high-energy electron irradiation, or showing microstructural evolution occurring under ion beam irradiation. Such observations have revolutionized our understanding of how properties of metals and alloys change in the extreme radiation and thermal environments of a fission or a fusion power plant. The key feature of in situ electron microscopy is its ability to exhibit the time-dependent dynamics of migration, interaction, and transformation of radiation defects, and to visualize the entire complexity of evolving defect and dislocation networks. For example, in situ electron microscope observations provided evidence of violation of the Burgers vector conservation law for dislocations on the nanoscale. This gave a vital clue needed for modeling microscopic processes responsible for the formation of unusual high temperature dislocation structures in iron, and for explaining the origin of the

  6. A study of process-related electrical defects in SOI lateral bipolar transistors fabricated by ion implantation

    Yau, J.-B.; Cai, J.; Hashemi, P.; Balakrishnan, K.; D'Emic, C.; Ning, T. H.

    2018-04-01

    We report a systematic study of process-related electrical defects in symmetric lateral NPN transistors on silicon-on-insulator (SOI) fabricated using ion implantation for all the doped regions. A primary objective of this study is to see if pipe defects (emitter-collector shorts caused by locally enhanced dopant diffusion) are a show stopper for such bipolar technology. Measurements of IC-VCE and Gummel currents in parallel-connected transistor chains as a function of post-fabrication rapid thermal anneal cycles allow several process-related electrical defects to be identified. They include defective emitter-base and collector-base diodes, pipe defects, and defects associated with a dopant-deficient region in an extrinsic base adjacent its intrinsic base. There is no evidence of pipe defects being a major concern in SOI lateral bipolar transistors.

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

    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.

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

    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.

  9. Detection and depth determination of corrosion defects in embedded bolts using ultrasonic testing technique

    Lin, Shan; Fukutomi, Hiroyuki; Yuya, Hideki; Ito, Keisuke

    2011-01-01

    A great number of anchor bolts are used to fix various components to concrete foundation in thermal and nuclear power plants. As aging power plants degrade, it is feared that defects resulted from corrosion may occur underground. In this paper, a measurement method utilizing the phased array technique is developed to detect such defects. Measurement results show that this method can detect local and circumferential corrosion defects introduced artificially, but defect echo position appears to be farther away from the bolt head than is actually the case. A finite element simulation of wave propagation shows that longitudinal waves excited by a phased array probe are mode converted and reflected at the defect and at bolt wall, which results in the position of the defect echo appearing to be farther away than the defect actually is. Moreover, an approach for determining the depth of defects using measurement results is also proposed based on numerical results. The depths determined by the proposed approach agree with the actual depths with a maximum error of 1.8 mm and a RMSE of 1.06 mm. (author)

  10. Failures and Defects in the Building Process

    Jørgensen, Kirsten

    2009-01-01

    Function failures, defects, mistakes and poor communication are major problems for the construction sector. As the empirical element in the research, a large construction site was observed from the very start to the very end and all failures and defects of a certain size were recorded and analysed...

  11. Treatment of osteochondral defects of the talus

    van Bergen, C. J. A.; de Leeuw, P. A. J.; van Dijk, C. N.

    2008-01-01

    This review article provides a current concepts overview of osteochondral defects of the talus, with special emphasis on treatment options, their indications and future developments. Osteochondral defects of the talar dome are mostly caused by a traumatic event. They may lead to deep ankle pain on

  12. Indicators for Building Process without Final Defects -

    Jørgensen, Kirsten; Rasmussen, Grane Mikael Gregaard; Thuesen, Christian Langhoff

    2011-01-01

    This article introduces the preliminary data analysis, as well as the underlying theories and methods for identifying the indicators for building process without final defects. Since 2004, the Benchmark Centre for the Danish Construction Sector (BEC) has collected information about legal defects...

  13. Positron analysis of defects in metals

    van Veen, A.; Kruseman, A.C.; Schut, H.; Mijnarends, P.E.; Kooi, B.J.; de Hosson, J.T.M.; Jean, YC; Eldrup, M; Schrader, DM; West, RN

    1997-01-01

    New methods are discussed to improve defect analysis. The first method employs mapping of two shape parameters, S and W, of the positron annihilation photopeak. It is demonstrated that the combined use of S and W allows to a better discrimination of defects. The other method is based on background

  14. Birth defects in children with newborn encephalopathy

    Felix, JF; Badawi, N; Kurinczuk, JJ; Bower, C; Keogh, JM; Pemberton, PJ

    2000-01-01

    This study was designed to investigate birth defects found in association with newborn encephalopathy. All possible birth defects were ascertained in a population-based study of 276 term infants with moderate or severe encephalopathy and 564 unmatched term control infants. A strong association

  15. Iodide-trapping defect of the thyroid

    Pannall, P.R.; Steyn, A.F.; Van Reenen, O.

    1978-01-01

    We describe a grossly hypothyroid 50-year-old woman, mentally retarded since birth. On the basis of her history of recurrent goitre, absence of 131 I neck uptake and a low saliva/plasma 131 I ratio, congenital hypothyroidism due to a defect of the iodide-trapping mechanism was diagnosed. Other family members studied did not have the defect

  16. Impurity Role In Mechanically Induced Defects

    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

  17. Defect-Tolerant Monolayer Transition Metal Dichalcogenides

    Pandey, Mohnish; Rasmussen, Filip Anselm; Kuhar, Korina

    2016-01-01

    Localized electronic states formed inside the band gap of a semiconductor due to crystal defects can be detrimental to the material's optoelectronic properties. Semiconductors with a lower tendency to form defect induced deep gap states are termed defect-tolerant. Here we provide a systematic first...... the gap. These ideas are made quantitative by introducing a descriptor that measures the degree of similarity of the conduction and valence band manifolds. Finally, the study is generalized to nonpolar nanoribbons of the TMDs where we find that only the defect sensitive materials form edge states within......-principles investigation of defect tolerance in 29 monolayer transition metal dichalcogenides (TMDs) of interest for nanoscale optoelectronics. We find that the TMDs based on group VI and X metals form deep gap states upon creation of a chalcogen (S, Se, Te) vacancy, while the TMDs based on group IV metals form only...

  18. Teratology: from science to birth defects prevention.

    Rasmussen, Sonja A; Erickson, J David; Reef, Susan E; Ross, Danielle S

    2009-01-01

    One of the goals of birth defects research is to better understand risk or preventive factors for birth defects so that strategies for prevention can be developed. In this article, we have selected four areas of birth defects research that have led to the development of prevention strategies. These areas include rubella virus as a cause of congenital rubella syndrome, folic acid as a preventive factor for neural tube defects, cytomegalovirus infection as a cause of birth defects and developmental disabilities, and alcohol as a cause of fetal alcohol spectrum disorders. For each of these areas, we review key clinical and research findings that led to the identification of the risk or preventive factor, milestones in the development of prevention strategies, and the progress made thus far toward prevention.

  19. Defect accumulation under cascade damage conditions

    Trinkaus, H.; Singh, B.N.; Woo, C.H.

    1994-01-01

    in terms of this reaction kinetics taking into account cluster production, dissociation, migration and annihilation at extended sinks. Microstructural features which are characteristic of cascade damage and cannot be explained in terms of the conventional single defect reaction kinetics are emphasized......There is now ample evidence from both experimental and computer simulation studies that in displacement cascades not only intense recombination takes place but also efficient clustering of both self-interstitial atoms (SIAs) and vacancies. The size distributions of the two types of defects produced...... reactions kinetics associated with the specific features of cascade damage is described, with emphasis on asymmetries between SIA and vacancy type defects concerning their production, stability, mobility and interactions with other defects. Defect accumulation under cascade damage conditions is discussed...

  20. Defect pin behaviour in the DFR

    Sloss, W.M.; Bagley, K.Q.; Edmonds, E.; Potter, P.E.

    1979-01-01

    A program of defective fuel pin irradiations has been carried out in the DFR. This program employed fuel pins which had failed during previous irradiations (natural defects) and pins in which simulated failures (artificial defects) had been induced prior to irradiation or during an intermediate examination stage at moderate or substantial burnups. The artificial defects simulated longitudinal ruptures and were normally located at positions near the top, middle and bottom of the pin where clad temperatures were 450, 540 and 630 0 C respectively. The fuel was mixed U-Pu oxide, and fuel form, stoichiometry, clad type, pin diameter, linear rating, and burnup were among the variables examined. The defect pin tests were normally carried out in single pin or trefoil type vehicles. After irradiation all the pins were subjected to the normal nondestructive examination procedures and the visual, radiographic, gamma-scanning, and dimensional change results are presented. Several pins were destructively examined and the metallographic data are discussed

  1. Tritium releases, birth defects and infant deaths

    1991-01-01

    The AECB has published a report 'Tritium releases from the Pickering Nuclear Generating Station and Birth Defects and Infant Mortality in Nearby Communities 1971-1988' (report number INFO-0401). This presents the results of a detailed analysis of deaths and birth defects occurring in infants born to mothers living in the area (25 Km radius) of the Pickering nuclear power plant, over an 18-year period. The analysis looked at the frequency of these defects and deaths in comparison to the general rate for Ontario, and also in relation to airborne and waterborne releases of tritium from the power plant. The overall conclusion was that the rates of infant death and birth defects were generally not higher in the study population than in all of Ontario. There was no prevalent relationship between these deaths and defects and tritium releases measured either at the power plant or by ground monitoring stations t some distance from the facility

  2. Wafer plane inspection for advanced reticle defects

    Nagpal, Rajesh; Ghadiali, Firoz; Kim, Jun; Huang, Tracy; Pang, Song

    2008-05-01

    Readiness of new mask defect inspection technology is one of the key enablers for insertion & transition of the next generation technology from development into production. High volume production in mask shops and wafer fabs demands a reticle inspection system with superior sensitivity complemented by a low false defect rate to ensure fast turnaround of reticle repair and defect disposition (W. Chou et al 2007). Wafer Plane Inspection (WPI) is a novel approach to mask defect inspection, complementing the high resolution inspection capabilities of the TeraScanHR defect inspection system. WPI is accomplished by using the high resolution mask images to construct a physical mask model (D. Pettibone et al 1999). This mask model is then used to create the mask image in the wafer aerial plane. A threshold model is applied to enhance the inspectability of printing defects. WPI can eliminate the mask restrictions imposed on OPC solutions by inspection tool limitations in the past. Historically, minimum image restrictions were required to avoid nuisance inspection stops and/or subsequent loss of sensitivity to defects. WPI has the potential to eliminate these limitations by moving the mask defect inspections to the wafer plane. This paper outlines Wafer Plane Inspection technology, and explores the application of this technology to advanced reticle inspection. A total of twelve representative critical layers were inspected using WPI die-to-die mode. The results from scanning these advanced reticles have shown that applying WPI with a pixel size of 90nm (WPI P90) captures all the defects of interest (DOI) with low false defect detection rates. In validating CD predictions, the delta CDs from WPI are compared against Aerial Imaging Measurement System (AIMS), where a good correlation is established between WPI and AIMSTM.

  3. Defect identification in semiconductors with positron annihilation: experiment and theory

    Tuomisto, Filip

    2015-03-01

    Positron annihilation spectroscopy is a very powerful technique for the detection, identification and quantification of vacancy-type defects in semiconductors. In the past decades, it has been used to reveal the relationship between opto-electronic properties and specific defects in a wide variety of materials - examples include parasitic yellow luminescence in GaN, dominant acceptor defects in ZnO and broad-band absorption causing brown coloration in natural diamond. In typical binary compound semiconductors, the selective sensitivity of the technique is rather strongly limited to cation vacancies that possess significant open volume and suitable charge (negative of neutral). On the other hand, oxygen vacancies in oxide semiconductors are a widely debated topic. The properties attributed to oxygen vacancies include the inherent n-type conduction, poor p-type dopability, coloration (absorption), deep level luminescence and non-radiative recombination, while the only direct experimental evidence of their existence has been obtained on the crystal surface. We will present recent advances in combining state-of-the-art positron annihilation experiments and ab initio computational approaches. The latter can be used to model both the positron lifetime and the electron-positron momentum distribution - quantities that can be directly compared with experimental results. We have applied these methods to study vacancy-type defects in III-nitride semiconductors (GaN, AlN, InN) and oxides such as ZnO, SnO2, In2O3andGa2O3. We will show that cation-vacancy-related defects are important compensating centers in all these materials when they are n-type. In addition, we will show that anion (N, O) vacancies can be detected when they appear as complexes with cation vacancies.

  4. bioA mutant of Mycobacterium tuberculosis shows severe growth defect and imparts protection against tuberculosis in guinea pigs

    Kar, Ritika; Nangpal, Prachi; Mathur, Shubhita; Singh, Swati

    2017-01-01

    Owing to the devastation caused by tuberculosis along with the unsatisfactory performance of the Bacillus Calmette–Guérin (BCG) vaccine, a more efficient vaccine than BCG is required for the global control of tuberculosis. A number of studies have demonstrated an essential role of biotin biosynthesis in the growth and survival of several microorganisms, including mycobacteria, through deletion of the genes involved in de novo biotin biosynthesis. In this study, we demonstrate that a bioA mutant of Mycobacterium tuberculosis (MtbΔbioA) is highly attenuated in the guinea pig model of tuberculosis when administered aerogenically as well as intradermally. Immunization with MtbΔbioA conferred significant protection in guinea pigs against an aerosol challenge with virulent M. tuberculosis, when compared with the unvaccinated animals. Booster immunization with MtbΔbioA offered no advantage over a single immunization. These experiments demonstrate the vaccinogenic potential of the attenuated M. tuberculosis bioA mutant against tuberculosis. PMID:28658275

  5. bioA mutant of Mycobacterium tuberculosis shows severe growth defect and imparts protection against tuberculosis in guinea pigs.

    Ritika Kar

    Full Text Available Owing to the devastation caused by tuberculosis along with the unsatisfactory performance of the Bacillus Calmette-Guérin (BCG vaccine, a more efficient vaccine than BCG is required for the global control of tuberculosis. A number of studies have demonstrated an essential role of biotin biosynthesis in the growth and survival of several microorganisms, including mycobacteria, through deletion of the genes involved in de novo biotin biosynthesis. In this study, we demonstrate that a bioA mutant of Mycobacterium tuberculosis (MtbΔbioA is highly attenuated in the guinea pig model of tuberculosis when administered aerogenically as well as intradermally. Immunization with MtbΔbioA conferred significant protection in guinea pigs against an aerosol challenge with virulent M. tuberculosis, when compared with the unvaccinated animals. Booster immunization with MtbΔbioA offered no advantage over a single immunization. These experiments demonstrate the vaccinogenic potential of the attenuated M. tuberculosis bioA mutant against tuberculosis.

  6. How to 'visualize' lattice defects

    Doi, Kenji

    1974-01-01

    Methods to recognize objects are discussed. In case of optics, lenses are used, and light from objects passing through the lenses focuses on focal planes. The amplitude of light on the focal planes in given as a function of the structure factor of scattering light from objects, images of objects are made on image planes. In case of X-ray or neutron diffraction, lenses which make images by X-ray or neutrons can not be made, accordingly images cannot be obtained. Images can be seen with electron microscopes. By X-ray or thermal neutron diffraction, intensity on focal planes in observed, and the defects to be studied are recognized as diffuse scattering. Since it is necessary to minimize aberration in case of image observation with electron microscopes, slits are used to utilize electron beam near optical axis exclusively. Therefore large resolving power cannot be expected. The information concerning structure obtained from focal planes is of statistical nature, and that from image planes is local information. The principle of neutron topography, by which the informations concerning local points are obtained, is explained. A photograph of LiF irradiated by 0.5 MeV proton beam was taken by the topographic method, and shown in this paper. (Kato, T.)

  7. Optimal lot sizing in screening processes with returnable defective items

    Vishkaei, Behzad Maleki; Niaki, S. T. A.; Farhangi, Milad; Rashti, Mehdi Ebrahimnezhad Moghadam

    2014-07-01

    This paper is an extension of Hsu and Hsu (Int J Ind Eng Comput 3(5):939-948, 2012) aiming to determine the optimal order quantity of product batches that contain defective items with percentage nonconforming following a known probability density function. The orders are subject to 100 % screening process at a rate higher than the demand rate. Shortage is backordered, and defective items in each ordering cycle are stored in a warehouse to be returned to the supplier when a new order is received. Although the retailer does not sell defective items at a lower price and only trades perfect items (to avoid loss), a higher holding cost incurs to store defective items. Using the renewal-reward theorem, the optimal order and shortage quantities are determined. Some numerical examples are solved at the end to clarify the applicability of the proposed model and to compare the new policy to an existing one. The results show that the new policy provides better expected profit per time.

  8. Weyl geometry and the nonlinear mechanics of distributed point defects

    Yavari, A.

    2012-09-05

    The residual stress field of a nonlinear elastic solid with a spherically symmetric distribution of point defects is obtained explicitly using methods from differential geometry. The material manifold of a solid with distributed point defects-where the body is stress-free-is a flat Weyl manifold, i.e. a manifold with an affine connection that has non-metricity with vanishing traceless part, but both its torsion and curvature tensors vanish. Given a spherically symmetric point defect distribution, we construct its Weyl material manifold using the method of Cartan\\'s moving frames. Having the material manifold, the anelasticity problem is transformed to a nonlinear elasticity problem and reduces the problem of computing the residual stresses to finding an embedding into the Euclidean ambient space. In the case of incompressible neo-Hookean solids, we calculate explicitly this residual stress field. We consider the example of a finite ball and a point defect distribution uniform in a smaller ball and vanishing elsewhere. We show that the residual stress field inside the smaller ball is uniform and hydrostatic. We also prove a nonlinear analogue of Eshelby\\'s celebrated inclusion problem for a spherical inclusion in an isotropic incompressible nonlinear solid. © 2012 The Royal Society.

  9. Reduced TCA Flux in Diabetic Myotubes: Determined by Single Defects?

    Gaster, Michael

    2012-01-01

    The diabetic phenotype is complex, requiring elucidation of key initiating defects. Diabetic myotubes express a primary reduced tricarboxylic acid (TCA) cycle flux but at present it is unclear in which part of the TCA cycle the defect is localised. In order to localise the defect we studied ATP production in isolated mitochondria from substrates entering the TCA cycle at various points. ATP production was measured by luminescence with or without concomitant ATP utilisation by hexokinase in mitochondria isolated from myotubes established from eight lean and eight type 2 diabetic subjects. The ATP production of investigated substrate combinations was significantly reduced in mitochondria isolated from type 2 diabetic subjects compared to lean. However, when ATP synthesis rates at different substrate combinations were normalized to the corresponding individual pyruvate-malate rate, there was no significant difference between groups. These results show that the primary reduced TCA cycle flux in diabetic myotubes is not explained by defects in specific part of the TCA cycle but rather results from a general downregulation of the TCA cycle.

  10. Porosity Defect Remodeling and Tensile Analysis of Cast Steel

    Linfeng Sun

    2016-02-01

    Full Text Available Tensile properties on ASTM A216 WCB cast steel with centerline porosity defect were studied with radiographic mapping and finite element remodeling technique. Non-linear elastic and plastic behaviors dependent on porosity were mathematically described by relevant equation sets. According to the ASTM E8 tensile test standard, matrix and defect specimens were machined into two categories by two types of height. After applying radiographic inspection, defect morphologies were mapped to the mid-sections of the finite element models and the porosity fraction fields had been generated with interpolation method. ABAQUS input parameters were confirmed by trial simulations to the matrix specimen and comparison with experimental outcomes. Fine agreements of the result curves between simulations and experiments could be observed, and predicted positions of the tensile fracture were found to be in accordance with the tests. Chord modulus was used to obtain the equivalent elastic stiffness because of the non-linear features. The results showed that elongation was the most influenced term to the defect cast steel, compared with elastic stiffness and yield stress. Additional visual explanations on the tensile fracture caused by void propagation were also given by the result contours at different mechanical stages, including distributions of Mises stress and plastic strain.

  11. Defective ribosome assembly in Shwachman-Diamond syndrome.

    Wong, Chi C; Traynor, David; Basse, Nicolas; Kay, Robert R; Warren, Alan J

    2011-10-20

    Shwachman-Diamond syndrome (SDS), a recessive leukemia predisposition disorder characterized by bone marrow failure, exocrine pancreatic insufficiency, skeletal abnormalities and poor growth, is caused by mutations in the highly conserved SBDS gene. Here, we test the hypothesis that defective ribosome biogenesis underlies the pathogenesis of SDS. We create conditional mutants in the essential SBDS ortholog of the ancient eukaryote Dictyostelium discoideum using temperature-sensitive, self-splicing inteins, showing that mutant cells fail to grow at the restrictive temperature because ribosomal subunit joining is markedly impaired. Remarkably, wild type human SBDS complements the growth and ribosome assembly defects in mutant Dictyostelium cells, but disease-associated human SBDS variants are defective. SBDS directly interacts with the GTPase elongation factor-like 1 (EFL1) on nascent 60S subunits in vivo and together they catalyze eviction of the ribosome antiassociation factor eukaryotic initiation factor 6 (eIF6), a prerequisite for the translational activation of ribosomes. Importantly, lymphoblasts from SDS patients harbor a striking defect in ribosomal subunit joining whose magnitude is inversely proportional to the level of SBDS protein. These findings in Dictyostelium and SDS patient cells provide compelling support for the hypothesis that SDS is a ribosomopathy caused by corruption of an essential cytoplasmic step in 60S subunit maturation.

  12. Topological defects in confined populations of spindle-shaped cells

    Duclos, Guillaume; Erlenkämper, Christoph; Joanny, Jean-François; Silberzan, Pascal

    2017-01-01

    Most spindle-shaped cells (including smooth muscles and sarcomas) organize in vivo into well-aligned `nematic’ domains, creating intrinsic topological defects that may be used to probe the behaviour of these active nematic systems. Active non-cellular nematics have been shown to be dominated by activity, yielding complex chaotic flows. However, the regime in which live spindle-shaped cells operate, and the importance of cell-substrate friction in particular, remains largely unexplored. Using in vitro experiments, we show that these active cellular nematics operate in a regime in which activity is effectively damped by friction, and that the interaction between defects is controlled by the system’s elastic nematic energy. Due to the activity of the cells, these defects behave as self-propelled particles and pairwise annihilate until all displacements freeze as cell crowding increases. When confined in mesoscopic circular domains, the system evolves towards two identical +1/2 disclinations facing each other. The most likely reduced positions of these defects are independent of the size of the disk, the cells’ activity or even the cell type, but are well described by equilibrium liquid crystal theory. These cell-based systems thus operate in a regime more stable than other active nematics, which may be necessary for their biological function.

  13. Enhanced defect of interest [DOI] monitoring by utilizing sensitive inspection and ADRTrue SEM review

    Kirsch, Remo; Zeiske, Ulrich; Shabtay, Saar; Beyer, Mirko; Yerushalmi, Liran; Goshen, Oren

    2011-03-01

    As semiconductor process design rules continue to shrink, the ability of optical inspection tools to separate between true defects and nuisance becomes more and more difficult. Therefore, monitoring Defect of Interest (DOI) become a real challenge (Figure 1). This phenomenon occurs due to the lower signal received from real defects while noise levels remain almost the same, resulting in inspection high nuisance rate, which jeopardizes the ability to provide a meaningful, true defect Pareto. A non-representative defect Pareto creates a real challenge to a reliable process monitoring (Figure 4). Traditionally, inspection tool recipes were optimized to keep data load at a manageable level and provide defect maps with ~10% nuisance rate, but as defects of interest get smaller with design rule shrinkage, this requirement results in a painful compromise in detection sensitivity. The inspection is usually followed by defect review and classification using scanning electron microscope (SEM), the classification done manually and it is performed on a small sample of the inspection defect map due to time and manual resources limitations. Sample is usually 50~60 randomly selected locations, review is performed manually most of the times, and manual classification is performed for all the reviewed locations. In the approach described in this paper, the inspection tool recipe is optimized for sensitivity rather than low nuisance rate (i.e. detect all DOI with compromising on a higher nuisance rate). Inspection results with high nuisance rate introduce new challenges for SEM review methodology & tools. This paper describe a new approach which enhances process monitoring quality and the results of collaborative work of the Process Diagnostic & Control Business Unit of Applied Materials® and GLOBALFOUNDRIES® utilizing Applied Materials ADRTrueTM & SEMVisionTM capabilities. The study shows that the new approach reveals new defect types in the Pareto, and improves the ability to

  14. Evaluation and Visualization of Surface Defects - a Numerical and Experimental Study on Sheet-Metal Parts

    Andersson, A.

    2005-01-01

    The ability to predict surface defects in outer panels is of vital importance in the automotive industry, especially for brands in the premium car segment. Today, measures to prevent these defects can not be taken until a test part has been manufactured, which requires a great deal of time and expense. The decision as to whether a certain surface is of acceptable quality or not is based on subjective evaluation. It is quite possible to detect a defect by measurement, but it is not possible to correlate measured defects and the subjective evaluation. If all results could be based on the same criteria, it would be possible to compare a surface by both FE simulations, experiments and subjective evaluation with the same result.In order to find a solution concerning the prediction of surface defects, a laboratory tool was manufactured and analysed both experimentally and numerically. The tool represents the area around a fuel filler lid and the aim was to recreate surface defects, so-called 'teddy bear ears'. A major problem with the evaluation of such defects is that the panels are evaluated manually and to a great extent subjectivity is involved in the classification and judgement of the defects. In this study the same computer software was used for the evaluation of both the experimental and the numerical results. In this software the surface defects were indicated by a change in the curvature of the panel. The results showed good agreement between numerical and experimental results. Furthermore, the evaluation software gave a good indication of the appearance of the surface defects compared to an analysis done in existing tools for surface quality measurements. Since the agreement between numerical and experimental results was good, this indicates that these tools can be used for an early verification of surface defects in outer panels

  15. Defect-band mediated ferromagnetism in Gd-doped ZnO thin films

    Venkatesh, S.

    2015-01-07

    Gd-doped ZnO thin films prepared by pulsed laser deposition with Gd concentrations varying from 0.02–0.45 atomic percent (at. %) showed deposition oxygen pressure controlled ferromagnetism. Thin films prepared with Gd dopant levels (showed that the ferromagnetic exchange is mediated by a spin-split defect band formed due to oxygen deficiency related defect complexes. Mott\\'s theory of variable range of hopping conduction confirms the formation of the impurity/defect band near the Fermi level.

  16. Characterization of the structure and chemistry of defects in materials

    Larson, B.C.; Ruehle, M.; Seidman, D.N.

    1988-01-01

    Research programs, presented at the materials research symposium, on defects in materials are presented. Major areas include: point defects, defect aggregates, and ordering; defects in non-metals and semiconductors; atomic resolution imaging of defects; and gain boundaries, interfaces, and layered materials. Individual projects are processed separately for the data bases

  17. Enteric neurons show a primary cilium.

    Luesma, Ma José; Cantarero, Irene; Castiella, Tomás; Soriano, Mario; Garcia-Verdugo, José Manuel; Junquera, Concepción

    2013-01-01

    The primary cilium is a non-motile cilium whose structure is 9+0. It is involved in co-ordinating cellular signal transduction pathways, developmental processes and tissue homeostasis. Defects in the structure or function of the primary cilium underlie numerous human diseases, collectively termed ciliopathies. The presence of single cilia in the central nervous system (CNS) is well documented, including some choroid plexus cells, neural stem cells, neurons and astrocytes, but the presence of primary cilia in differentiated neurons of the enteric nervous system (ENS) has not yet been described in mammals to the best of our knowledge. The enteric nervous system closely resembles the central nervous system. In fact, the ultrastructure of the ENS is more similar to the CNS ultrastructure than to the rest of the peripheral nervous system. This research work describes for the first time the ultrastructural characteristics of the single cilium in neurons of rat duodenum myenteric plexus, and reviews the cilium function in the CNS to propose the possible role of cilia in the ENS cells. © 2012 The Authors. Published by Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

  18. A novel method to alleviate flash-line defects in coining process

    Xu, Jiangping; Khan, Kamran; El Sayed, Tamer S.

    2013-01-01

    with the reported experimental results. We also propose a novel method of redesigning the rim geometry of the workpiece to alleviate the flash-line defects which also shows good agreement with experiments. © 2012 Elsevier Inc. All rights reserved.

  19. Entropy Crisis, Defects and the Role of Competition in Monatomic Glass Formers

    Gujrati, P. D.

    2007-01-01

    We establish the existence of an entropy crisis in monatomic glass formers. The work finally shows that the entropy crisis is ubiqutous in all supercooled liquids. We also study the roles of defects and energetic competition on the ideal glass.

  20. Defect-band mediated ferromagnetism in Gd-doped ZnO thin films

    Venkatesh, S.; Franklin, J. B.; Ryan, M. P.; Lee, J.-S.; Ohldag, Hendrik; McLachlan, M. A.; Alford, N. M.; Roqan, Iman S.

    2015-01-01

    . %) at low oxygen deposition pressure (<25 mTorr) were ferromagnetic at room temperature. Negative magnetoresistance, electric transport properties showed that the ferromagnetic exchange is mediated by a spin-split defect band formed due to oxygen deficiency

  1. Formation of Defect-Free Latex Films on Porous Fiber Supports

    Lively, Ryan P.; Mysona, Joshua A.; Chance, Ronald R.; Koros, William J.

    2011-01-01

    a defect-free lumen-side barrier layer can be created. Film experiments examined the effect of drying rate, latex age, substrate porosity (porous vs nonporous), and substrate hydrophobicity/ hydrophilicity. Film studies show that in ideal conditions

  2. Distribution of defects in wind turbine blades and reliability assessment of blades containing defects

    Stensgaard Toft, Henrik; Branner, Kim; Berring, Peter

    2009-01-01

    on the assumption that one error in the production process tends to trigger several defects. For both models additional information about number, type and size of the defects is included as stochastic variables. The probability of failure for a wind turbine blade will not only depend on variations in the material......In the present paper two stochastic models for the distribution of defects in wind turbine blades are proposed. The first model assumes that the individual defects are completely randomly distributed in the blade. The second model assumes that the defects occur in clusters of different size based...... properties and the load but also on potential defects in the blades. As a numerical example the probability of failure is calculated for the main spar both with and without defects in terms of delaminations. The delaminations increase the probability of failure compared to a perfect blade, but by applying...

  3. Impact of interstitial iron on the study of meta-stable B-O defects in Czochralski silicon: Further evidence of a single defect

    Kim, Moonyong; Chen, Daniel; Abbott, Malcolm; Nampalli, Nitin; Wenham, Stuart; Stefani, Bruno; Hallam, Brett

    2018-04-01

    We explore the influence of interstitial iron (Fei) on lifetime spectroscopy of boron-oxygen (B-O) related degradation in p-type Czochralski silicon. Theoretical and experimental evidence presented in this study indicate that iron-boron pair (Fe-B) related reactions could have influenced several key experimental results used to derive theories on the fundamental properties of the B-O defect. Firstly, the presence of Fei can account for higher apparent capture cross-section ratios (k) of approximately 100 observed in previous studies during early stages of B-O related degradation. Secondly, the association of Fe-B pairs can explain the initial stage of a two-stage recovery of carrier lifetime with dark annealing after partial degradation. Thirdly, Fei can result in high apparent k values after the permanent deactivation of B-O defects. Subsequently, we show that a single k value can describe the recombination properties associated with B-O defects throughout degradation, that the recovery during dark annealing occurs with a single-stage, and both the fast- and slow-stage B-O related degradation can be permanently deactivated during illuminated annealing. Accounting for the recombination activity of Fei provides further evidence that the B-O defect is a single defect, rather than two separate defects normally attributed to fast-forming recombination centers and slow-forming recombination centers. Implications of this finding for the nature of the B-O defect are also discussed.

  4. Effect of noise on defect chaos in a reaction-diffusion model.

    Wang, Hongli; Ouyang, Qi

    2005-06-01

    The influence of noise on defect chaos due to breakup of spiral waves through Doppler and Eckhaus instabilities is investigated numerically with a modified Fitzhugh-Nagumo model. By numerical simulations we show that the noise can drastically enhance the creation and annihilation rates of topological defects. The noise-free probability distribution function for defects in this model is found not to fit with the previously reported squared-Poisson distribution. Under the influence of noise, the distributions are flattened, and can fit with the squared-Poisson or the modified-Poisson distribution. The defect lifetime and diffusive property of defects under the influence of noise are also checked in this model.

  5. Application of Ultrasonic Phased Array Technology to the Detection of Defect in Composite Stiffened-structures

    Zhou, Yuan-Qi; Zhan, Li-Hua

    2016-05-01

    Composite stiffened-structure consists of the skin and stringer has been widely used in aircraft fuselage and wings. The main purpose of the article is to detect the composite material reinforced structure accurately and explore the relationship between defect formation and structural elements or curing process. Based on ultrasonic phased array inspection technology, the regularity of defects in the manufacture of composite materials are obtained, the correlation model between actual defects and nondestructive testing are established. The article find that the forming quality of deltoid area in T-stiffened structure is obviously improved by pre-curing, the defects of hat-stiffened structure are affected by the mandrel. The results show that the ultrasonic phased array inspection technology can be an effectively way for the detection of composite stiffened-structures, which become an important means to control the defects of composite and improve the quality of the product.

  6. A defect model for UO2+x based on electrical conductivity and deviation from stoichiometry measurements

    Garcia, Philippe; Pizzi, Elisabetta; Dorado, Boris; Andersson, David; Crocombette, Jean-Paul; Martial, Chantal; Baldinozzi, Guido; Siméone, David; Maillard, Serge; Martin, Guillaume

    2017-10-01

    Electrical conductivity of UO2+x shows a strong dependence upon oxygen partial pressure and temperature which may be interpreted in terms of prevailing point defects. A simulation of this property along with deviation from stoichiometry is carried out based on a model that takes into account the presence of impurities, oxygen interstitials, oxygen vacancies, holes, electrons and clusters of oxygen atoms. The equilibrium constants for each defect reaction are determined to reproduce the experimental data. An estimate of defect concentrations and their dependence upon oxygen partial pressure can then be determined. The simulations carried out for 8 different temperatures (973-1673 K) over a wide range of oxygen partial pressures are discussed and resulting defect equilibrium constants are plotted in an Arrhenius diagram. This provides an estimate of defect formation energies which may further be compared to other experimental data or ab-initio and empirical potential calculations.

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

    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.

  8. Bone tissue ultrastructural defects in a mouse model for osteogenesis imperfecta: a Raman spectroscopy study

    Chen, Tsoching; Kozloff, Kenneth M.; Goldstein, Steven A.; Morris, Michael D.

    2004-07-01

    Osteogenesis imperfecta (OI) is genetic defect in which the genes that code for the α1(I) or α2(I) chains of type I collagen are defective. The defects often result in substitution of a bulky amino acid for glycine, causing formation of collagen that can not form the normal triple helix. Depending on the details of the defects, the outcomes range from controllable to lethal. This study focuses on OI type IV, a more common and moderately severe form of the disease. People with the disease have a substantial increase in the risk and rate of fracture. We examine the spectroscopic consequences of these defects, using a mouse model (BRTL) that mimics OI type IV. We compare Raman images from tibial cortical tissue of wild-type mice and BRTL mice with single copy of mutation and show that both mineral to matrix ratios and collagen inter-fibril cross-links are different in wild-type and mutant mice.

  9. Oxidation behavior of graphene-coated copper at intrinsic graphene defects of different origins.

    Kwak, Jinsung; Jo, Yongsu; Park, Soon-Dong; Kim, Na Yeon; Kim, Se-Yang; Shin, Hyung-Joon; Lee, Zonghoon; Kim, Sung Youb; Kwon, Soon-Yong

    2017-11-16

    The development of ultrathin barrier films is vital to the advanced semiconductor industry. Graphene appears to hold promise as a protective coating; however, the polycrystalline and defective nature of engineered graphene hinders its practical applications. Here, we investigate the oxidation behavior of graphene-coated Cu foils at intrinsic graphene defects of different origins. Macro-scale information regarding the spatial distribution and oxidation resistance of various graphene defects is readily obtained using optical and electron microscopies after the hot-plate annealing. The controlled oxidation experiments reveal that the degree of structural deficiency is strongly dependent on the origins of the structural defects, the crystallographic orientations of the underlying Cu grains, the growth conditions of graphene, and the kinetics of the graphene growth. The obtained experimental and theoretical results show that oxygen radicals, decomposed from water molecules in ambient air, are effectively inverted at Stone-Wales defects into the graphene/Cu interface with the assistance of facilitators.

  10. Structural and electronic properties of zigzag InP nanoribbons with Stone–Wales type defects

    Longo, R C; Carrete, J; Varela, L M; Gallego, L J

    2016-01-01

    By means of density-functional-theoretic calculations, we investigate the structural and electronic properties of a hexagonal InP sheet and of hydrogen-passivated zigzag InP nanoribbons (ZInPNRs) with Stone–Wales (SW)-type defects. Our results show that the influence of this kind of defect is not limited to the defected region but it leads to the formation of ripples that extend across the systems, in keeping with the results obtained recently for graphene and silicene sheets. The presence of SW defects in ZInPNRs causes an appreciable broadening of the band gap and transforms the indirect-bandgap perfect ZInPNR into a direct-bandgap semiconductor. An external transverse electric field, regardless of its direction, reduces the gap in both the perfect and defective ZInPNRs. (paper)

  11. Defect-tuning exchange bias of ferromagnet/antiferromagnet core/shell nanoparticles by numerical study

    Mao Zhongquan; Chen Xi; Zhan Xiaozhi

    2012-01-01

    The influence of non-magnetic defects on the exchange bias (EB) of ferromagnet (FM)/antiferromagnet (AFM) core/shell nanoparticles is studied by Monte Carlo simulations. It is found that the EB can be tuned by defects in different positions. Defects at both the AFM and FM interfaces reduce the EB field while they enhance the coercive field by decreasing the effective interface coupling. However, the EB field and the coercive field show respectively a non-monotonic and a monotonic dependence on the defect concentration when the defects are located inside the AFM shell, indicating a similar microscopic mechanism to that proposed in the domain state model. These results suggest a way to optimize the EB effect for applications. (paper)

  12. Quantitative Evaluation of Defect Based on Ultrasonic Guided Wave and CHMM

    Chen Le

    2016-01-01

    Full Text Available The axial length of pipe defects is not linear with the reflection coefficient, which is difficult to identify the axial length of the defect by the reflection coefficient method. Continuous Hidden Markov Model (CHMM is proposed to accurately classify the axial length of defects, achieving the objective of preliminary quantitative evaluation. Firstly, wavelet packet decomposition method is used to extract the characteristic information of the guided wave signal, and Kernel Sliced Inverse Regression (KSIR method is used to reduce the dimension of feature set. Then, a variety of CHMM models are trained for classification. Finally, the trained models are used to identify the artificial corrosion defects on the outer surface of the pipe. The results show that the CHMM model has better robustness and can accurately identify the axial defects.

  13. Three-dimensional characterization of extreme ultraviolet mask blank defects by interference contrast photoemission electron microscopy.

    Lin, Jingquan; Weber, Nils; Escher, Matthias; Maul, Jochen; Han, Hak-Seung; Merkel, Michael; Wurm, Stefan; Schönhense, Gerd; Kleineberg, Ulf

    2008-09-29

    A photoemission electron microscope based on a new contrast mechanism "interference contrast" is applied to characterize extreme ultraviolet lithography mask blank defects. Inspection results show that positioning of interference destructive condition (node of standing wave field) on surface of multilayer in the local region of a phase defect is necessary to obtain best visibility of the defect on mask blank. A comparative experiment reveals superiority of the interference contrast photoemission electron microscope (Extreme UV illumination) over a topographic contrast one (UV illumination with Hg discharge lamp) in detecting extreme ultraviolet mask blank phase defects. A depth-resolved detection of a mask blank defect, either by measuring anti-node peak shift in the EUV-PEEM image under varying inspection wavelength condition or by counting interference fringes with a fixed illumination wavelength, is discussed.

  14. Treatment experience of surgical repair for long-term skull defect

    Shou-cheng FAN

    2015-12-01

    Full Text Available Retrospective analysis was performed on 30 patients of skull defect who underwent surgical repair. Intraoperative and postoperative curative effect was evaluated on those patients, and the results showed that the incidence rate of intraoperative dura mater defect (P = 0.001, early postoperative complications [new epilepsy (P = 0.035 and effusion (P = 0.021] and late postoperative complications [foreign body sensation (P = 0.035 and dizziness and headache (P = 0.050] in long-term skull defect group were all higher than those in control group. In conclusion, surgical repair of long-term skull defect incurring high risk and various complications will not be an ideal management. Therefore, early surgical treatment for skull defect is suggested. DOI: 10.3969/j.issn.1672-6731.2015.12.016

  15. Risk factors predisposing to congenital heart defects

    Ul Haq, Faheem; Jalil, Fatima; Hashmi, Saman; Jumani, Maliha Iqbal; Imdad, Aamer; Jabeen, Mehnaz; Hashmi, Javad Tauseef; Irfan, Furqan Bin; Imran, Muhammad; Atiq, Mehnaz

    2011-01-01

    Congenital heart disease (CHD) is associated with multiple risk factors, consanguinity may be one such significant factor. The role of consanguinity in the etiology of CHD is supported by inbreeding studies, which demonstrate an autosomal recessive pattern of inheritance of some congenital heart defects. This study was done to find out the risk factors for CHD. A case-control study was done on pediatric patients at a tertiary care hospital, Aga Khan University Hospital, located in Karachi, Pakistan. A total of 500 patients, 250 cases and 250 controls were included in the study. Amongst the 250 cases (i.e. those diagnosed with CHD), 122 patients (48.8%) were born of consanguineous marriages while in the controls (i.e. non-CHD) only 72 patients (28.9%) showed a consanguinity amongst parents. On multivariate analysis, consanguinity emerged as an independent risk factor for CHD; adjusted odds ratio 2.59 (95% C. I. 1.73 - 3.87). Other risk factors included low birth weight, maternal co-morbidities, family history of CHD and first born child. On the other hand, medications used by the mother during the index pregnancy, maternal age and gender of the child did not significantly increase the risk of developing CHD. Analyses of our results show that parental consanguinity, family history of CHD, maternal co-morbidities, first born child and low birth weight are independent risk factors for CHD

  16. Reduction in Defect Content in ODS Alloys

    Ritherdon, J.; Jones, A.R.

    2000-02-01

    The work detailed within this report is a continuation of earlier work that was carried out under contract number IDX-SY382V. The earlier work comprised a literature review of the sources and types of defects found principally in Fe-based ODS alloys together with a series of experiments designed to identify defects in ODS Fe{sub 3}Al material and recommend methods of defect reduction. Defects found in the Mechanically Alloyed (MA) ODS Fe{sub 3}Al included regions of incomplete MA, porosity, intrusions and fine-grained stringers. Some defects tended to be found in association with one another e.g. intrusions and fine-grained stringers. Preliminary powder separation experiments were also performed. The scope and objectives of the present work were laid out in the technical proposal ``Reduction in Defect Content in ODS Alloys--II'' which formed the basis of amendment 3 of the current contract. The current studies were devised in the context of the preceding work with a view to extending and concluding certain experiments while exploring new avenues of investigation of defect control and reduction where appropriate. All work proposed was within the context of achieving an ODS Fe{sub 3}Al alloy of improved overall quality and potential creep performance (particularly) in the consolidated, release condition. The interim outturn of the experimental work performed is also reported.

  17. Modeling of Powder Bed Manufacturing Defects

    Mindt, H.-W.; Desmaison, O.; Megahed, M.; Peralta, A.; Neumann, J.

    2018-01-01

    Powder bed additive manufacturing offers unmatched capabilities. The deposition resolution achieved is extremely high enabling the production of innovative functional products and materials. Achieving the desired final quality is, however, hampered by many potential defects that have to be managed in due course of the manufacturing process. Defects observed in products manufactured via powder bed fusion have been studied experimentally. In this effort we have relied on experiments reported in the literature and—when experimental data were not sufficient—we have performed additional experiments providing an extended foundation for defect analysis. There is large interest in reducing the effort and cost of additive manufacturing process qualification and certification using integrated computational material engineering. A prerequisite is, however, that numerical methods can indeed capture defects. A multiscale multiphysics platform is developed and applied to predict and explain the origin of several defects that have been observed experimentally during laser-based powder bed fusion processes. The models utilized are briefly introduced. The ability of the models to capture the observed defects is verified. The root cause of the defects is explained by analyzing the numerical results thus confirming the ability of numerical methods to provide a foundation for rapid process qualification.

  18. Human diseases associated with defective DNA repair

    Friedberg, E.C.; Ehmann, U.K.; Williams, J.I.

    1979-01-01

    The observations on xeroderma pigmentosum (XP) cells in culture were the first indications of defective DNA repair in association with human disease. Since then, a wealth of information on DNA repair in XP, and to a lesser extent in other diseases, has accumulated in the literature. Rather than clarifying the understanding of DNA repair mechanisms in normal cells and of defective DNA repair in human disease, the literature suggests an extraordinary complexity of both of the phenomena. In this review a number of discrete human diseases are considered separately. An attempt was made to systematically describe the pertinent clinical features and cellular and biochemical defects in these diseases, with an emphasis on defects in DNA metabolism, particularly DNA repair. Wherever possible observations have been correlated and unifying hypotheses presented concerning the nature of the basic defect(s) in these diseases. Discussions of the following diseases are presented: XP, ataxia telangiectasia; Fanconi's anemia; Hutchinson-Gilford progeria syndrome; Bloom's syndrome, Cockayne's syndrome; Down's syndrome; retinoblastoma; chronic lymphocytic leukemia; and other miscellaneous human diseases with possble DNA repair defects

  19. Extrusion product defects: a statistical study

    Qamar, S.Z.; Arif, A.F.M.; Sheikh, A.K.

    2003-01-01

    In any manufacturing environment, defects resulting in rework or rejection are directly related to product cost and quality, and indirectly linked with process, tooling and product design. An analysis of product defects is therefore integral to any attempt at improving productivity, efficiency and quality. Commercial aluminum extrusion is generally a hot working process and consists of a series of different but integrated operations: billet preheating and sizing, die set and container preheating, billet loading and deformation, product sizing and stretching/roll-correction, age hardening, and painting/anodizing. Product defects can be traced back to problems in billet material and preparation, die and die set design and maintenance, process variable aberrations (ram speed, extrusion pressure, container temperature, etc), and post-extrusion treatment (age hardening, painting/anodizing, etc). The current paper attempts to analyze statistically the product defects commonly encountered in a commercial hot aluminum extrusion setup. Real-world rejection data, covering a period of nine years, has been researched and collected from a local structural aluminum extrusion facility. Rejection probabilities have been calculated for all the defects studied. The nine-year rejection data have been statistically analyzed on the basis of (i) an overall breakdown of defects, (ii) year-wise rejection behavior, (iii) breakdown of defects in each of three cost centers: press, anodizing, and painting. (author)

  20. Exploring atomic defects in molybdenum disulphide monolayers

    Hong, Jinhua; Hu, Zhixin; Probert, Matt; Li, Kun; Lv, Danhui; Yang, Xinan; Gu, Lin; Mao, Nannan; Feng, Qingliang; Xie, Liming; Zhang, Jin; Wu, Dianzhong; Zhang, Zhiyong; Jin, Chuanhong; Ji, Wei; Zhang, Xixiang; Yuan, Jun; Zhang, Ze

    2015-01-01

    Defects usually play an important role in tailoring various properties of two-dimensional materials. Defects in two-dimensional monolayer molybdenum disulphide may be responsible for large variation of electric and optical properties. Here we present a comprehensive joint experiment-theory investigation of point defects in monolayer molybdenum disulphide prepared by mechanical exfoliation, physical and chemical vapour deposition. Defect species are systematically identified and their concentrations determined by aberration-corrected scanning transmission electron microscopy, and also studied by ab-initio calculation. Defect density up to 3.5 × 10 13 cm '2 is found and the dominant category of defects changes from sulphur vacancy in mechanical exfoliation and chemical vapour deposition samples to molybdenum antisite in physical vapour deposition samples. Influence of defects on electronic structure and charge-carrier mobility are predicted by calculation and observed by electric transport measurement. In light of these results, the growth of ultra-high-quality monolayer molybdenum disulphide appears a primary task for the community pursuing high-performance electronic devices.

  1. Platelet rich fibrin in jaw defects

    Nica, Diana; Ianes, Emilia; Pricop, Marius

    2016-03-01

    Platelet rich fibrin (PRF) is a tissue product of autologous origin abundant in growth factors, widely used in regenerative procedures. Aim of the study: Evaluation of the regenerative effect of PRF added in the bony defects (after tooth removal or after cystectomy) Material and methods: The comparative nonrandomized study included 22 patients divided into 2 groups. The first group (the test group) included 10 patients where the bony defects were treated without any harvesting material. The second group included 12 patients where the bony defects were filled with PRF. The bony defect design was not critical, with one to two walls missing. After the surgeries, a close clinically monitoring was carried out. The selected cases were investigated using both cone beam computer tomography (CBCT) and radiographic techniques after 10 weeks postoperatively. Results: Faster bone regeneration was observed in the bony defects filled with PRF comparing with the not grafted bony defects. Conclusions: PRF added in the bony defects accelerates the bone regeneration. This simplifies the surgical procedures and decreases the economic costs.

  2. Exploring atomic defects in molybdenum disulphide monolayers

    Hong, Jinhua

    2015-02-19

    Defects usually play an important role in tailoring various properties of two-dimensional materials. Defects in two-dimensional monolayer molybdenum disulphide may be responsible for large variation of electric and optical properties. Here we present a comprehensive joint experiment-theory investigation of point defects in monolayer molybdenum disulphide prepared by mechanical exfoliation, physical and chemical vapour deposition. Defect species are systematically identified and their concentrations determined by aberration-corrected scanning transmission electron microscopy, and also studied by ab-initio calculation. Defect density up to 3.5 × 10 13 cm \\'2 is found and the dominant category of defects changes from sulphur vacancy in mechanical exfoliation and chemical vapour deposition samples to molybdenum antisite in physical vapour deposition samples. Influence of defects on electronic structure and charge-carrier mobility are predicted by calculation and observed by electric transport measurement. In light of these results, the growth of ultra-high-quality monolayer molybdenum disulphide appears a primary task for the community pursuing high-performance electronic devices.

  3. Defect Chemistry of Oxides for Energy Applications.

    Schweke, Danielle; Mordehovitz, Yuval; Halabi, Mahdi; Shelly, Lee; Hayun, Shmuel

    2018-05-31

    Oxides are widely used for energy applications, as solid electrolytes in various solid oxide fuel cell devices or as catalysts (often associated with noble metal particles) for numerous reactions involving oxidation or reduction. Defects are the major factors governing the efficiency of a given oxide for the above applications. In this paper, the common defects in oxide systems and external factors influencing the defect concentration and distribution are presented, with special emphasis on ceria (CeO 2 ) based materials. It is shown that the behavior of a variety of oxide systems with respect to properties relevant for energy applications (conductivity and catalytic activity) can be rationalized by general considerations about the type and concentration of defects in the specific system. A new method based on transmission electron microscopy (TEM), recently reported by the authors for mapping space charge defects and measuring space charge potentials, is shown to be of potential importance for understanding conductivity mechanisms in oxides. The influence of defects on gas-surface reactions is exemplified on the interaction of CO 2 and H 2 O with ceria, by correlating between the defect distribution in the material and its adsorption capacity or splitting efficiency. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Estimates of point defect production in α-quartz using molecular dynamics simulations

    Cowen, Benjamin J.; El-Genk, Mohamed S.

    2017-07-01

    Molecular dynamics (MD) simulations are performed to investigate the production of point defects in α-quartz by oxygen and silicon primary knock-on atoms (PKAs) of 0.25-2 keV. The Wigner-Seitz (WS) defect analysis is used to identify the produced vacancies, interstitials, and antisites, and the coordination defect analysis is used to identify the under and over-coordinated oxygen and silicon atoms. The defects at the end of the ballistic phase and the residual defects, after annealing, increase with increased PKA energy, and are statistically the same for the oxygen and silicon PKAs. The WS defect analysis results show that the numbers of the oxygen vacancies and interstitials (VO, Oi) at the end of the ballistic phase is the highest, followed closely by those of the silicon vacancies and interstitials (VSi, Sii). The number of the residual oxygen and silicon vacancies and interstitials are statistically the same. In addition, the under-coordinated OI and SiIII, which are the primary defects during the ballistic phase, have high annealing efficiencies (>89%). The over-coordinated defects of OIII and SiV, which are not nearly as abundant in the ballistic phase, have much lower annealing efficiencies (PKA energy.

  5. Defect properties of CuCrO2: A density functional theory calculation

    Fang Zhi-Jie; Zhu Ji-Zhen; Zhou Jiang; Mo Man

    2012-01-01

    Using the first-principles methods, we study the formation energetics properties of intrinsic defects, and the charge doping properties of extrinsic defects in transparent conducting oxides CuCrO 2 . Intrinsic defects, some typical acceptor-type, and donor-type extrinsic defects in their relevant charge state are considered. By systematically calculating the formation energies and transition energy, the results of calculation show that, V Cu , O i , and O Cu are the relevant intrinsic defects in CuCrO 2 ; among these intrinsic defects, V Cu is the most efficient acceptor in CuCrO 2 . It is found that all the donor-type extrinsic defects have difficulty in inducing n-conductivity in CuCrO 2 because of their deep transition energy level. For all the acceptor-type extrinsic defects, substituting Mg for Cr is the most prominent doping acceptor with relative shallow transition energy levels in CuCrO 2 . Our calculation results are expected to be a guide for preparing promising n-type and p-type materials in CuCrO 2 . (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  6. Influence of cover defects on the attenuation of radon with earthen covers

    Kalkwarf, D.R.; Mayer, D.W.

    1983-11-01

    Experimental and theoretical evaluations of radon flux through laboratory-scale defective soil columns are presented together with a survey of literature on the formation and prevention of defects in soil covers. This report focuses on air-filled, centimeter-scale defects that are most probable in earthen covers for attenuating radon emission from uranium-mill tailings. Examples include shirnkage and erosion cracks, erosion piping, animal burrows and air channels formed by the biodegradation of vegetation roots. Calculations based on mathematical models indicate that collections of defects which could increase the radon flux from an earthen cover by a factor of two would be easily detected by visual inspection. However, these models ignore air-turbulence in the defect and drying of the soil around the defect. Laboratory measurements showed that turbulent diffusion of radon occurred through defects as narrow as 0.3 cm when subjected to a transverse air velocity of 1 to 6 miles per hour at the surface. Both turbulence and more-rapid drying of soil can accelerate radon flux to the cover surface. Consequently, recommended methods to inhibit defect formation should be applied. 29 references, 3 figures, 5 tables

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

    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)

  8. Nonlinear effects in defect production by atomic and molecular ion implantation

    David, C.; Dholakia, Manan; Chandra, Sharat; Nair, K. G. M.; Panigrahi, B. K.; Amirthapandian, S.; Amarendra, G.; Varghese Anto, C.; Santhana Raman, P.; Kennedy, John

    2015-01-01

    This report deals with studies concerning vacancy related defects created in silicon due to implantation of 200 keV per atom aluminium and its molecular ions up to a plurality of 4. The depth profiles of vacancy defects in samples in their as implanted condition are carried out by Doppler broadening spectroscopy using low energy positron beams. In contrast to studies in the literature reporting a progressive increase in damage with plurality, implantation of aluminium atomic and molecular ions up to Al 3 , resulted in production of similar concentration of vacancy defects. However, a drastic increase in vacancy defects is observed due to Al 4 implantation. The observed behavioural trend with respect to plurality has even translated to the number of vacancies locked in vacancy clusters, as determined through gold labelling experiments. The impact of aluminium atomic and molecular ions simulated using MD showed a monotonic increase in production of vacancy defects for cluster sizes up to 4. The trend in damage production with plurality has been explained on the basis of a defect evolution scheme in which for medium defect concentrations, there is a saturation of the as-implanted damage and an increase for higher defect concentrations

  9. THE INFRARED SPECTROSCOPY OF POLYCYCLIC AROMATIC HYDROCARBONS WITH FIVE- AND SEVEN-MEMBERED FUSED RING DEFECTS

    Ricca, Alessandra; Bauschlicher, Charles W. Jr; Allamandola, Louis J.

    2011-01-01

    Polycyclic aromatic hydrocarbon (PAH) growth and destruction are thought to proceed via the occasional incorporation of five- and seven-membered fused ring defects in the hexagonal carbon skeleton. Using density functional theory, this paper investigates the effect such five- and seven-membered fused ring defects have on the infrared spectra of ovalene, circumovalene, and circumcircumovalene. The defects make only small changes to the overall infrared (IR) spectra, both in the mid-IR and in the far-IR, of these species. In addition to small shifts in the positions of the bands between the PAHs with and without defects, the most common effect of the defects is to increase the number of bands. Except for an anion with the Stone-Wales defect, all of the species studied have the C-C stretching band at 6.3 μm or at longer wavelengths, the position in Classes B and C astronomical PAH spectra. In the case of the Stone-Wales anion, the band falls at 6.20 μm, suggesting that further study of defects is probably worthwhile, as some PAHs with defects might be important in those sources (Class A) that show a C-C stretching band that falls near 6.2 μm.

  10. Reversible defects on myocardial perfusion imaging early after coronary stent implantation: a predictor of late restenosis

    Kim, D. E.; Park, S. A.; Kim, C. K.; Chang, J. A.; Jeong, J. W.; Oh, S. G.; Lee, C.

    2007-01-01

    It appears logical that myocardial perfusion should be fixed and not reversible, in the territory supplied by a dilated coronary artery. However, several studies have demonstrated reversible perfusion in the territory supplied by a coronary artery with an optimally implanted stent. The main objective of this study was to evaluate the incidence of reversible defects detected by M-SPECT early after optimal PTCA with stent implantation. Its second objective was to determine the predictive value of detecting reversible defects after stent implantation for late restenosis. Sixty-six patients that underwent M-SPECT within 24 hours of successful PTCA with stent implantation were included. All patients were followed up clinically and angiographically. The incidence of reversible perfusion defects on M-SPECT and the rate of late restenosis in target coronary arteries were evaluated retrospectively. Reversible perfusion defects on M-SPECT were observed in 26% of the patients and in 36% of lesions following successful PTCA with stent implantation. The incidence of late restenosis was significantly higher in patients and lesions with reversible perfusion defects (47% vs. 18%). According to binary logistic regression analysis, the presence of a reversible perfusion defects was the only independent predictor of late restenosis. This study shows that the predictive value of reversible perfusion defects on M-SPECT early after stent implantation with respect to the incidence of late restenosis was 47% in patients with a reversible defect, and 18% in those without it

  11. Spin-wave dispersion of nanostructured magnonic crystals with periodic defects

    V. L. Zhang

    2016-11-01

    Full Text Available The spin-wave dispersions in nanostructured magnonic crystals with periodic defects have been mapped by Brillouin light scattering. The otherwise perfect crystals are one-dimensional arrays of alternating 460nm-wide Ni80Fe20 stripes and 40nm-wide air gaps, where one in ten Ni80Fe20 stripes is a defect of width other than 460 nm. Experimentally, the defects are manifested as additional Brillouin peaks, lying within the first and second bandgaps of the perfect crystal, whose frequencies decrease with increasing defect stripe width. Finite-element calculations, based on a supercell comprising one defect and nine perfect Py stripes, show that the defect modes are localized about the defects, with the localization exhibiting an approximate U-shaped dependence on defect size. Calculations also reveal extra magnon branches and the opening of mini-bandgaps, within the allowed bands of the perfect crystal, arising from Bragg reflections at the boundaries of the shorter supercell Brillouin zone. Simulated magnetization profiles of the band-edge modes of the major and mini-bandgaps reveal their different symmetries and localization properties. The findings could find application in microwave magnonic devices like single-frequency passband spin-wave filters.

  12. Elastic fields, dipole tensors, and interaction between self-interstitial atom defects in bcc transition metals

    Dudarev, S. L.; Ma, Pui-Wai

    2018-03-01

    Density functional theory (DFT) calculations show that self-interstitial atom (SIA) defects in nonmagnetic body-centered-cubic (bcc) metals adopt strongly anisotropic configurations, elongated in the direction [S. Han et al., Phys. Rev. B 66, 220101 (2002), 10.1103/PhysRevB.66.220101; D. Nguyen-Manh et al., Phys. Rev. B 73, 020101 (2006), 10.1103/PhysRevB.73.020101; P. M. Derlet et al., Phys. Rev. B 76, 054107 (2007), 10.1103/PhysRevB.76.054107; S. L. Dudarev, Annu. Rev. Mater. Res. 43, 35 (2013), 10.1146/annurev-matsci-071312-121626]. Elastic distortions, associated with such anisotropic atomic structures, appear similar to distortions around small prismatic dislocation loops, although the extent of this similarity has never been quantified. We derive analytical formulas for the dipole tensors of SIA defects, which show that, in addition to the prismatic dislocation looplike character, the elastic field of a SIA defect also has a significant isotropic dilatation component. Using empirical potentials and DFT calculations, we parametrize dipole tensors of defects for all the nonmagnetic bcc transition metals. This enables a quantitative evaluation of the energy of elastic interaction between the defects, which also shows that in a periodic three-dimensional simple cubic arrangement of crowdions, long-range elastic interactions between a defect and all its images favor a orientation of the defect.

  13. Reconstruction of Ligament and Tendon Defects Using Cell Technologies.

    Chailakhyan, R K; Shekhter, A B; Ivannikov, S V; Tel'pukhov, V I; Suslin, D S; Gerasimov, Yu V; Tonenkov, A M; Grosheva, A G; Panyushkin, P V; Moskvina, I L; Vorob'eva, N N; Bagratashvili, V N

    2017-02-01

    We studied the possibility of restoring the integrity of the Achilles tendon in rabbits using autologous multipotent stromal cells. Collagen or gelatin sponges populated with cells were placed in a resorbable Vicryl mesh tube and this tissue-engineered construct was introduced into a defect of the middle part of the Achilles tendon. In 4 months, histological analysis showed complete regeneration of the tendon with the formation of parallel collagen fibers, spindle-shaped tenocytes, and newly formed vessels.

  14. Periorbital cyst with bone defect in a dog

    Ito, K.; Asano, K.; Urano, T.; Ogiwara, N.; Seki, M.; Kato, Y.; Sasaki, Y.; Teshima, K.; Kutara, K.; Edamura, K.; Shibuya, H.; Tanaka, S.

    2006-01-01

    A 4-year-old female Miniature Dachshund was referred with a chief complaint of right periorbital swelling that had not responded to antibiotic therapy. Ultrasonography and fine-needle aspiration revealed that the periorbital lesion had a cystic structure without any inflammatory or neoplastic cells. Computed tomography (CT) showed that the cyst occupied a defect in the periorbital maxillary, lacrimal, and frontal bones and had invaded the nasal cavity. The lesion was histologically suspected by incisional biopsy as an epithelial cyst

  15. Interdisciplinary Management of an Isolated Intrabony Defect

    Sheetal Ghivari

    2014-01-01

    Full Text Available The treatment of intrabony defects is a real challenge in molar teeth as it is chronic, slowly progressing disease which needs timely intervention. Periodontal inflammation associated with intrabony defect is not a separate entity as it secondarily affects the pulp causing retrograde pulpitis. However, treatment of these lesions will be complicated due to extensive bone loss. The tooth was endodontically treated followed by periodontal surgery to eliminate the deep periodontal pocket and promote bone fill in osseous defect. PepGen P-15 composited with platelet rich plasma was utilized for enhancing bone formation. The combination of these graft materials provides synergistic effect on bone regeneration.

  16. Tibial and fibular developmental fields defects

    Khoury, N.J.; Haddad, M.C.; Hourani, M.H.

    1999-01-01

    Malformations of the lower limbs are rare and heterogeneous anomalies. To explain the diversity and complexity of these abnormalities, authors introduced the concept of tibial and fibular developmental fields. Defects in these fields are responsible for different malformations, which have been described, to our knowledge, in only one report in the radiology literature. We present a case of a newborn with femoral bifurcation, absent fibulae and talar bones, ankle and foot malformations, and associated atrial septal defect. Our case is an example of defects in both fibular and tibial developmental fields. (orig.)

  17. Dimensions of defects determined by radiographical testing

    Oesterberg, J.

    Normally industrial radiography using x-rays or radionuclides gives information on the existence of defects in welds. These defects may in some instances be harmless, the size of the flaw is important. Radiography may be used for determining the thickness of the defect in many cases, by measuring the blackening of the photographic film used. The report gives a theoretical treatment of the problems and goes on to practical examples of the application. For flaws that have a width of at least 0.3 mm, a thickness of the order 0.1 mm can be determined with sufficient accuracy in materials 40 mm thick.(P.Aa.)

  18. Analysis of probability of defects in the disposal canisters

    Holmberg, J.-E.; Kuusela, P.

    2011-06-01

    This report presents a probability model for the reliability of the spent nuclear waste final disposal canister. Reliability means here that the welding of the canister lid has no critical defects from the long-term safety point of view. From the reliability point of view, both the reliability of the welding process (that no critical defects will be born) and the non-destructive testing (NDT) process (all critical defects will be detected) are equally important. In the probability model, critical defects in a weld were simplified into a few types. Also the possibility of human errors in the NDT process was taken into account in a simple manner. At this moment there is very little representative data to determine the reliability of welding and also the data on NDT is not well suited for the needs of this study. Therefore calculations presented here are based on expert judgements and on several assumptions that have not been verified yet. The Bayesian probability model shows the importance of the uncertainty in the estimation of the reliability parameters. The effect of uncertainty is that the probability distribution of the number of defective canisters becomes flat for larger numbers of canisters compared to the binomial probability distribution in case of known parameter values. In order to reduce the uncertainty, more information is needed from both the reliability of the welding and NDT processes. It would also be important to analyse the role of human factors in these processes since their role is not reflected in typical test data which is used to estimate 'normal process variation'.The reported model should be seen as a tool to quantify the roles of different methods and procedures in the weld inspection process. (orig.)

  19. Knowledge of birth defects among nursing mothers in a developing ...

    sponsibility is placed on parents in the recognition of these defects. Objectives: The .... be prevented, detected, inherited or treated; and if they knew that folic ... could be used to prevent certain birth defects. ..... birth defects such as smoking.

  20. Vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association with Mayer-Rokitansky-Küster-Hauser syndrome in co-occurrence

    Bjørsum-Meyer, Thomas; Herlin, Morten; Qvist, Niels

    2016-01-01

    Background: The vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association and Mayer-Rokitansky-Küster-Hauser syndrome are rare conditions. We aimed to present two cases with the vertebral defect, anal atresia, cardiac...... defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association and Mayer-Rokitansky-Küster-Hauser co-occurrence from our local surgical center and through a systematic literature search detect published cases. Furthermore, we aimed to collect existing knowledge...... in the embryopathogenesis and genetics in order to discuss a possible link between the vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association and Mayer-Rokitansky-Küster-Hauser syndrome. Case presentation: Our first case was a white girl...

  1. ILT based defect simulation of inspection images accurately predicts mask defect printability on wafer

    Deep, Prakash; Paninjath, Sankaranarayanan; Pereira, Mark; Buck, Peter

    2016-05-01

    At advanced technology nodes mask complexity has been increased because of large-scale use of resolution enhancement technologies (RET) which includes Optical Proximity Correction (OPC), Inverse Lithography Technology (ILT) and Source Mask Optimization (SMO). The number of defects detected during inspection of such mask increased drastically and differentiation of critical and non-critical defects are more challenging, complex and time consuming. Because of significant defectivity of EUVL masks and non-availability of actinic inspection, it is important and also challenging to predict the criticality of defects for printability on wafer. This is one of the significant barriers for the adoption of EUVL for semiconductor manufacturing. Techniques to decide criticality of defects from images captured using non actinic inspection images is desired till actinic inspection is not available. High resolution inspection of photomask images detects many defects which are used for process and mask qualification. Repairing all defects is not practical and probably not required, however it's imperative to know which defects are severe enough to impact wafer before repair. Additionally, wafer printability check is always desired after repairing a defect. AIMSTM review is the industry standard for this, however doing AIMSTM review for all defects is expensive and very time consuming. Fast, accurate and an economical mechanism is desired which can predict defect printability on wafer accurately and quickly from images captured using high resolution inspection machine. Predicting defect printability from such images is challenging due to the fact that the high resolution images do not correlate with actual mask contours. The challenge is increased due to use of different optical condition during inspection other than actual scanner condition, and defects found in such images do not have correlation with actual impact on wafer. Our automated defect simulation tool predicts

  2. Holographic entanglement entropy of surface defects

    Gentle, Simon A.; Gutperle, Michael; Marasinou, Chrysostomos [Department of Physics and Astronomy, University of California,Los Angeles, CA 90095 (United States)

    2016-04-12

    We calculate the holographic entanglement entropy in type IIB supergravity solutions that are dual to half-BPS disorder-type surface defects in N=4 supersymmetric Yang-Mills theory. The entanglement entropy is calculated for a ball-shaped region bisected by a surface defect. Using the bubbling supergravity solutions we also compute the expectation value of the defect operator. Combining our result with the previously-calculated one-point function of the stress tensor in the presence of the defect, we adapt the calculation of Lewkowycz and Maldacena http://dx.doi.org/10.1007/JHEP05(2014)025 to obtain a second expression for the entanglement entropy. Our two expressions agree up to an additional term, whose possible origin and significance is discussed.

  3. Holographic entanglement entropy of surface defects

    Gentle, Simon A.; Gutperle, Michael; Marasinou, Chrysostomos

    2016-01-01

    We calculate the holographic entanglement entropy in type IIB supergravity solutions that are dual to half-BPS disorder-type surface defects in N=4 supersymmetric Yang-Mills theory. The entanglement entropy is calculated for a ball-shaped region bisected by a surface defect. Using the bubbling supergravity solutions we also compute the expectation value of the defect operator. Combining our result with the previously-calculated one-point function of the stress tensor in the presence of the defect, we adapt the calculation of Lewkowycz and Maldacena http://dx.doi.org/10.1007/JHEP05(2014)025 to obtain a second expression for the entanglement entropy. Our two expressions agree up to an additional term, whose possible origin and significance is discussed.

  4. Di-interstitial defect in silicon revisited

    Londos, C. A.; Antonaras, G.; Chroneos, A.

    2013-01-01

    Infrared spectroscopy was used to study the defect spectrum of Cz-Si samples following fast neutron irradiation. We mainly focus on the band at 533 cm −1 , which disappears from the spectra at ∼170 °C, exhibiting similar thermal stability with the Si-P6 electron paramagnetic resonance (EPR) spectrum previously correlated with the di-interstitial defect. The suggested structural model of this defect comprises of two self-interstitial atoms located symmetrically around a lattice site Si atom. The band anneals out following a first-order kinetics with an activation energy of 0.88 ± 0.3 eV. This value does not deviate considerably from previously quoted experimental and theoretical values for the di-interstitial defect. The present results indicate that the 533 cm −1 IR band originates from the same structure as that of the Si-P6 EPR spectrum

  5. Microcephaly and Other Birth Defects: Zika

    ... Español (Spanish) Recommend on Facebook Tweet Share Compartir Zika and Microcephaly Microcephaly is a birth defect in ... pregnancy or has stopped growing after birth. Congenital Zika Syndrome Congenital Zika syndrome is a unique pattern ...

  6. Ultrasonic determination of the size of defects

    Zetterwall, T.

    1989-01-01

    The paper presents results from a study of ultrasonic testing of materials. The main topic has been the determination of the size, length and deep, of cracks or defects in stainless steel plates. (K.A.E)

  7. Focal skin defect, limb anomalies and microphthalmia.

    Jackson, K.E.; Andersson, H.C.

    2004-01-01

    We describe two unrelated female patients with congenital single focal skin defects, unilateral microphthalmia and limb anomalies. Growth and psychomotor development were normal and no brain malformation was detected. Although eye and limb anomalies are commonly associated, clinical anophthalmia and

  8. Genetic Counseling for Congenital Heart Defects

    ... 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 ...

  9. Reduction of Defects in Jewelry Manufacturing

    Ayudhya, Phitchaya Phanomwan na; Tangjitsitcharoen, Somkiat

    2017-06-01

    The aim of this research was to reduce the defects of gem bracelet found during manufacturing process at a jewelry company. It was found that gem bracelet product has the highest rejects compared to the rejects found in ring, earring, and pendant products. Types of defect were classified by using Pareto Diagram consisting of gem falling, seam, unclean casting, impinge, and deformation. The causes of defect were analyzed by Cause and Effect Diagram and applied Failure Mode and Effects Analysis (FMEA) was applied during manufacturing processes. This research found that the improvement of manufacturing process could reduce the Risk Priority Number (RPN) and total of all defects by 48.70% and 48.89%, respectively.

  10. Dental Enamel Defects and Celiac Disease

    ... Digestive System & How it Works Zollinger-Ellison Syndrome Dental Enamel Defects and Celiac Disease Celiac disease manifestations ... affecting any organ or body system. One manifestation—dental enamel defects—can help dentists and other health ...

  11. Creation of radiation defects in KCl crystals

    Lushchik, A.Ch.; Pung, L.A.; Khaldre, Yu.Yu.; Kolk, Yu.V.

    1981-01-01

    Optical and EPR methods were used to study the creation of anion and cation Frenkel defects in KCl crystals irradiated by X-ray and VUV-radiation. The decay of excitons with the creation of charged Frenkel defects (α and I centres) was detected and investigated at 4.2 K. The decay of excitons as well as the recombination of electrons with self-trapped holes leads to the creation of neutral Frenkel defects (F and H centres). The creation of Cl 3 - and Vsub(F) centres (cation vacancy is a component of these centres) by X-irradiation at 80 K proves the possibility of cation defects creation in KCl [ru

  12. Infrared computations of defect Schur indices

    Córdova, Clay [School of Natural Sciences, Institute for Advanced Study,1 Einstein Dr., Princeton, NJ (United States); Gaiotto, Davide [Perimeter Institute for Theoretical Physics,31 Caroline St., Waterloo, Ontario, N2L 2Y5 (Canada); Shao, Shu-Heng [Jefferson Physical Laboratory, Harvard University,17 Oxford St., Cambridge, MA (United States); School of Natural Sciences, Institute for Advanced Study,1 Einstein Dr., Princeton, NJ (United States)

    2016-11-18

    We conjecture a formula for the Schur index of four-dimensional N=2 theories in the presence of boundary conditions and/or line defects, in terms of the low-energy effective Seiberg-Witten description of the system together with massive BPS excitations. We test our proposal in a variety of examples for SU(2) gauge theories, either conformal or asymptotically free. We use the conjecture to compute these defect-enriched Schur indices for theories which lack a Lagrangian description, such as Argyres-Douglas theories. We demonstrate in various examples that line defect indices can be expressed as sums of characters of the associated two-dimensional chiral algebra and that for Argyres-Douglas theories the line defect OPE reduces in the index to the Verlinde algebra.

  13. Intrinsic defects in 3D printed materials

    Bolton, Christopher; Dagastine, Raymond

    2015-01-01

    We discuss the impact of bulk structural defects on the coherence, phase and polarisation of light passing through transparent 3D printed materials fabricated using a variety of commercial print technologies.

  14. International conference on defects in insulating crystals

    1977-01-01

    Short summaries of conference papers are presented. Some of the conference topics included transport properties, defect levels, superionic conductors, radiation effects, John-Teller effect, electron-lattice interactions, and relaxed excited states

  15. Apparatus for locating defective nuclear fuel elements

    Lawrie, W.E.

    1979-01-01

    An ultrasonic search unit for locating defective fuel elements within a fuel assembly used in a water cooled nuclear reactor is presented. The unit is capable of freely traversing the restricted spaces between the fuel elements

  16. Point defects dynamics in a stress field

    Smetniansky de De Grande, Nelida.

    1989-01-01

    The dependence of anisotropic defect diffusion on stress is studied for a hexagonal close packed (hcp) material under irradiation and uniaxially stressed. The diffusion is described as a discrete process of thermally activated jumps. It is shown that the presence of an external stress field enhances the intrinsic anisotropic diffusion, being this variation determined by the defect dipole tensors' symmetry in the equilibrium and saddle point configurations. Also, the point defect diffusion equations to sinks, like edge dislocations and spherical cavities, are solved and the sink strengths are calculated. The conclusion is that the dynamics of the interaction between defects and sinks is controlled by the changes in diffusivity induced by stress fields. (Author) [es

  17. Genetics Home Reference: abdominal wall defect

    ... 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) ...

  18. Defect networks and supersymmetric loop operators

    Bullimore, Mathew [Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Waterloo, ON N2L 2Y5 (Canada)

    2015-02-10

    We consider topological defect networks with junctions in A{sub N−1} Toda CFT and the connection to supersymmetric loop operators in N=2 theories of class S on a four-sphere. Correlation functions in the presence of topological defect networks are computed by exploiting the monodromy of conformal blocks, generalising the notion of a Verlinde operator. Concentrating on a class of topological defects in A{sub 2} Toda theory, we find that the Verlinde operators generate an algebra whose structure is determined by a set of generalised skein relations that encode the representation theory of a quantum group. In the second half of the paper, we explore the dictionary between topological defect networks and supersymmetric loop operators in the N=2{sup ∗} theory by comparing to exact localisation computations. In this context, the the generalised skein relations are related to the operator product expansion of loop operators.

  19. Electronic structure of point defects in semiconductors

    Bruneval, Fabien

    2014-01-01

    This 'Habilitation a diriger des Recherches' memoir presents most of my scientific activities during the past 7 years, in the field of electronic structure calculations of defects in solids. Point defects (vacancies, interstitials, impurities) in functional materials are a key parameter to determine if these materials will actually fill the role they have been assigned or not. Indeed, the presence of defects cannot be avoided when the temperature is increased or when the material is subjected to external stresses, such as irradiation in the nuclear reactors and in artificial satellites with solar radiations. However, in many cases, defects are introduced in the materials on purpose to tune the electronic transport, optical or even magnetic properties. This procedure is called the doping of semiconductors, which is the foundation technique for transistors, diodes, or photovoltaic cells. However, doping is not always straightforward and unexpected features may occur, such as doping asymmetry or Fermi level pinning, which can only be explained by complex phenomena involving different types of defects or complexes of defects. In this context, the calculations of electronic structure ab initio is an ideal tool to complement the experimental observations, to gain the understanding of phenomena at the atomic level, and even to predict the properties of defects. The power of the ab initio calculations comes from their ability to describe any system of electrons and nuclei without any specific adjustment. But although there is a strong need for numerical simulations in this field, the ab initio calculations for defects are still under development as of today. The work presented in this memoir summarizes my contributions to methodological developments on this subject. These developments have followed two main tracks. The first topic is the better understanding of the unavoidable finite size effects. Indeed, defects in semiconductors or insulators are generally present in

  20. Elastic interaction energies of defect structures

    Seitz, E.; de Fontaine, D.

    1976-01-01

    The elastic strain energy between point defects and small disk-shaped clusters of defects are calculated to determine stable configurations. A distortion tensor of tetragonal symmetry is assigned to each impurity atom. The tetragonality ratio t is varied to cover needle-type (t greater than 1), spherical (t = 1) and disk-type (t less than 0) strain fields. To vary the elastic properties of the host material, Fe, Cu, Al, and V were chosen as examples. Computer calculations are based on the microscopic theory of elasticity which emphasizes calculations in discrete Fourier space. Pairs of point defects order along [001] for t less than 1 and along (001) for t = 1 for all host elements. For t greater than 1 fcc lattices and bcc lattices behave differently. It is shown that only certain three dimensional periodic arrangements of parallel and perpendicular disk-like defect clusters are realized for given tetragonality ratio t and host element