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Sample records for reversible postreceptor defect

  1. Insulin resistance and postreceptor changes of liver metabolism in fat-fed mice

    DEFF Research Database (Denmark)

    Hedeskov, Carl Jørgen; Capito, Kirsten; Hansen, Svend Erik

    1992-01-01

    Medicinsk biokemi, animal diabetes, insulin resistance, postreceptor defects, liver metabolism, high-fat diet......Medicinsk biokemi, animal diabetes, insulin resistance, postreceptor defects, liver metabolism, high-fat diet...

  2. Postreceptor defects causing insulin resistance in normoinsulinemic non-insulin-dependent diabetes mellitus

    International Nuclear Information System (INIS)

    Bolinder, J.; Ostman, J.; Arner, P.

    1982-01-01

    The mechanisms of the diminished hypoglycemic response to insulin in non-insulin-dependent diabetes mellitus (NIDDM) with normal levels of circulating plasma insulin were investigated. Specific binding of mono- 125 I (Tyr A14)-insulin to isolated adipocytes and effects of insulin (5--10,000 microunits/ml) on glucose oxidation and lipolysis were determined simultaneously in subcutaneous adipose tissue of seven healthy subjects of normal weight and seven untreated NIDDM patients with normal plasma insulin levels. The two groups were matched for age, sex, and body weight. Insulin binding, measured in terms of receptor number and affinity, was normal in NIDDM, the total number of receptors averaging 350,000 per cell. Neither sensitivity nor the maximum antilipolytic effect of insulin was altered in NIDDM patients as compared with control subjects; the insulin concentration producing half the maximum effect (ED50) was 10 microunits/ml. As regards the effect of insulin on glucose oxidation, for the control subjects ED50 was 30 microunits/ml, whereas in NIDDM patients, insulin exerted no stimulatory effect. The results obtained suggest that the effect of insulin on glucose utilization in normoinsulinemic NIDDM may be diminished in spite of normal insulin binding to receptors. The resistance may be due solely to postreceptor defects, and does not involve antilipolysis

  3. Correlated cone noise decreases rod signal contributions to the post-receptoral pathways.

    Science.gov (United States)

    Hathibelagal, Amithavikram R; Feigl, Beatrix; Zele, Andrew J

    2018-04-01

    This study investigated how invisible extrinsic temporal white noise that correlates with the activity of one of the three [magnocellular (MC), parvocellular (PC), or koniocellular (KC)] post-receptoral pathways alters mesopic rod signaling. A four-primary photostimulator provided independent control of the rod and three cone photoreceptor excitations. The rod contributions to the three post-receptoral pathways were estimated by perceptually matching a 20% contrast rod pulse by independently varying the LMS (MC pathway), +L-M (PC pathway), and S-cone (KC pathway) excitations. We show that extrinsic cone noise caused a predominant decrease in the overall magnitude and ratio of the rod contributions to each pathway. Thus, the relative cone activity in the post-receptoral pathways determines the relative mesopic rod inputs to each pathway.

  4. Normalization of TAM post-receptor signaling reveals a cell invasive signature for Axl tyrosine kinase.

    Science.gov (United States)

    Kimani, Stanley G; Kumar, Sushil; Davra, Viralkumar; Chang, Yun-Juan; Kasikara, Canan; Geng, Ke; Tsou, Wen-I; Wang, Shenyan; Hoque, Mainul; Boháč, Andrej; Lewis-Antes, Anita; De Lorenzo, Mariana S; Kotenko, Sergei V; Birge, Raymond B

    2016-09-06

    Tyro3, Axl, and Mertk (TAMs) are a family of three conserved receptor tyrosine kinases that have pleiotropic roles in innate immunity and homeostasis and when overexpressed in cancer cells can drive tumorigenesis. In the present study, we engineered EGFR/TAM chimeric receptors (EGFR/Tyro3, EGFR/Axl, and EGF/Mertk) with the goals to interrogate post-receptor functions of TAMs, and query whether TAMs have unique or overlapping post-receptor activation profiles. Stable expression of EGFR/TAMs in EGFR-deficient CHO cells afforded robust EGF inducible TAM receptor phosphorylation and activation of downstream signaling. Using a series of unbiased screening approaches, that include kinome-view analysis, phosphor-arrays, RNAseq/GSEA analysis, as well as cell biological and in vivo readouts, we provide evidence that each TAM has unique post-receptor signaling platforms and identify an intrinsic role for Axl that impinges on cell motility and invasion compared to Tyro3 and Mertk. These studies demonstrate that TAM show unique post-receptor signatures that impinge on distinct gene expression profiles and tumorigenic outcomes.

  5. Reverse Abdominoplasty Flap in Reconstruction of Post-Bilateral Mastectomies Anterior Chest Wall Defect

    Directory of Open Access Journals (Sweden)

    William HC Tiong

    2014-01-01

    Full Text Available Reverse abdominoplasty was originally described for epigastric lift. Since the work by Baroudi and Huger in the 1970s, it has become clear that reverse abdominoplasty application can be extended beyond just aesthetic procedure. Through the knowledge of anterior abdominal wall vascularity, its application had included reconstructive prospect in the coverage of various chest wall defects. To date, reverse abdominoplasty flap has been used to reconstruct unilateral anterior chest wall defect or for larger defect but only in combination with other reconstructive techniques. Here, we presented a case where it is used as a standalone flap to reconstruct bilateral anterior chest wall soft tissue defect post-bilateral mastectomies in oncological resection. In conclusion, reverse abdominoplasty flap provided us with a simple, faster, and satisfactory reconstructive outcome.

  6. Reversible defects on myocardial perfusion imaging early after coronary stent implantation: a predictor of late restenosis

    International Nuclear Information System (INIS)

    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

  7. Effect of thallium-201 blood levels on reversible myocardial defects

    International Nuclear Information System (INIS)

    Nelson, C.W.; Wilson, R.A.; Angello, D.A.; Palac, R.T.

    1989-01-01

    To determine if 201 Tl plasma blood levels correlate with the presence of reversible myocardial defects during exercise testing, 14 patients with stable coronary artery disease underwent two separate exercise 201 Tl stress tests. Between initial and delayed imaging, on one test the patients drank an instant breakfast drink (eating) and on the other they drank an equivalent volume of water as a control (H 2 O). Thallium-201 imaging was performed immediately postexercise, immediately after eating/H 2 O and 210 min after eating/H 2 O. Between initial and immediate post eating/H 2 O images 201Tl reversible defects occurred in 27/38 regions in the H 2 O test versus 15/38 regions in the eating test (p = 0.02). Over this early time period, plasma 201 Tl activity was significantly higher in the H 2 O test than eating test (p less than 0.05). In conclusion, early reversal of 201 Tl defects may, in part, be the result of higher plasma 201 Tl activity early after initial postexercise 201 Tl imaging

  8. A Baseline-Free Defect Imaging Technique in Plates Using Time Reversal of Lamb Waves

    International Nuclear Information System (INIS)

    Jeong, Hyunjo; Cho, Sungjong; Wei, Wei

    2011-01-01

    We present an analytical investigation for a baseline-free imaging of a defect in plate-like structures using the time-reversal of Lamb waves. We first consider the flexural wave (A 0 mode) propagation in a plate containing a defect, and reception and time reversal process of the output signal at the receiver. The received output signal is then composed of two parts: a directly propagated wave and a scattered wave from the defect. The time reversal of these waves recovers the original input signal, and produces two additional sidebands that contain the time-of-flight information on the defect location. One of the side-band signals is then extracted as a pure defect signal. A defect localization image is then constructed from a beamforming technique based on the time-frequency analysis of the side band signal for each transducer pair in a network of sensors. The simulation results show that the proposed scheme enables the accurate, baseline-free imaging of a defect. (fundamental areas of phenomenology(including applications))

  9. Covering the Dorsal Finger Defect with Reverse Cross Finger Flap

    Directory of Open Access Journals (Sweden)

    Kaan Gurbuz

    2014-12-01

    Full Text Available Reconstruction of finger extensor zone defects with or without tendon gaps still remains a challenge for surgeons. Although surgical treatments may differ, and range from the use of local, regional, to free flaps, the outcomes for all cases are not satisfactory. In this case report, we present a case of a 3rd finger extensor side crush injury including a defect of Dd (Digit Dorsal 1, Dd2 and Dd3 defects of extensor zones with tendon gap. Tendon gap was reconstructed using m. palmaris longus tendon graft and the defect was covered with reversed cross-finger flap (random pattern with good cosmetic and excellent functional results.

  10. Vulval defect after pelvic trauma and its repair with reverse TRAM flap

    African Journals Online (AJOL)

    Introduction: In trauma, a vulval defect may result from avulsion injury or develops after a wound infection with or without necrosis in the event of infected heamatoma formation. Patient: We present a case report of a patient who had a vulval defect following pelvic trauma and its subsequent successful repair with a reversed ...

  11. Reverse peroneal artery flap for large defects of ankle and foot: A reliable reconstructive technique

    Directory of Open Access Journals (Sweden)

    Jose Tharayil

    2012-01-01

    Full Text Available Background: Large soft tissue defects around the lower third of the leg, ankle and foot always have been challenging to reconstruct. Reverse sural flaps have been used for this problem with variable success. Free tissue transfer has revolutionised management of these problem wounds in selected cases. Materials and Methods: Twenty-two patients with large defects around the lower third of the leg, ankle and foot underwent reconstruction with reverse peroneal artery flap (RPAF over a period of 7 years. The mean age of these patients was 41.2 years. Results: Of the 22 flaps, 21 showed complete survival without even marginal necrosis. One flap failed, where atherosclerotic occlusion of peroneal artery was evident on the table. Few patients had minor donor site problems that settled with conservative management. Conclusions: RPAF is a very reliable flap for the coverage of large soft tissue defects of the heel, sole and dorsum of foot. This flap adds versatility in planning and execution of this extended reverse sural flap.

  12. Late reversibility of tomographic myocardial thallium-201 defects: an accurate marker of myocardial viability

    International Nuclear Information System (INIS)

    Kiat, H.; Berman, D.S.; Maddahi, J.; De Yang, L.; Van Train, K.; Rozanski, A.; Friedman, J.

    1988-01-01

    Twenty-one patients were studied who underwent thallium-201 stress-redistribution single photon emission computed tomography (SPECT) both before and after coronary artery bypass grafting (n = 15) or transluminal coronary angioplasty (n = 6). All patients underwent thallium imaging 15 min, 4 h and late (18 to 72 h) after stress as part of the preintervention thallium-201 scintigram. In a total of 201 tomographic myocardial segments with definite post-stress thallium-201 perfusion defects in which the relevant coronary arteries were subsequently successfully reperfused, the 4 h redistribution images did not predict the postintervention scintigraphic improvement: 67 (85%) of the 79 4 h reversible as well as 88 (72%) of the 122 4 h nonreversible segments improved (p = NS). The 18 to 72 h late redistribution images effectively subcategorized the 4 h nonreversible segments with respect to postintervention scintigraphic improvement: 70 (95%) of the 74 late reversible segments improved after intervention, whereas only 18 (37%) of the 48 late nonreversible segments improved (p less than 0.0001). The frequency of late reversible defects and the frequency of postrevascularization improvement of late nonreversible defects are probably overestimated by this study because of referral biases. The cardiac counts and target to background ratios from late redistribution studies resulted in satisfactory cardiac images for visual interpretation. For optimal assessment of the extent of viable myocardium by thallium-201 scintigraphic studies, late redistribution imaging should be performed when nonreversible defects are observed on 4 h redistribution images

  13. Numerical Simulation of Ultrasonic Time Reversal Mirror in a Plate with Defect

    Czech Academy of Sciences Publication Activity Database

    Převorovský, Zdeněk; Krofta, Josef

    2008-01-01

    Roč. 13, č. 3 (2008), s. 1-5 ISSN 1435-4934. [NDT in Progress. Praha, 05.11.2007-07.11.2007] R&D Projects: GA ČR GA106/07/1393; GA ČR GA103/06/1711 Institutional research plan: CEZ:AV0Z20760514 Keywords : defect detection * nonlinear ultrasonic spectroscopy * time reversal mirror Subject RIV: BI - Acoustics http://www.ndt.net/ search /docs.php3?showForm=off&edit=1&MainSource=53&AuthorID=2812

  14. Extended Islanded Reverse Sural Artery Flap for Staged Reconstruction of Foot Defects Proximal to Toes

    International Nuclear Information System (INIS)

    Yousaf, M.A.; Abidin, Z.U.; Khalid, K.; Haq, A.U.; Tarar, F.A.; Asif, M.U.; Tarar, M.N.

    2018-01-01

    To assess the outcome of extended delayed reverse sural artery flap for reconstruction of foot defects proximal to toes in terms of flap survival, complication and extended area. Study Design:Case series. Place and Duration of Study:Jinnah Burn and Reconstructive Surgery Centre, Lahore, from February 2015 to April 2017. Methodology:Cases who underwent delayed sural artery flap were inducted. Preoperative hand-held doppler was done to confirm the location of perforator. Two suitable perforators were chosen to raise the extended flap by crossing the proximal limit in all cases. The pedicle was kept minimum 3 cm wide and perfusion was assessed. Flap was delayed for one week and vaccum-assisted closure (VAC) dressing was applied over wound. The second surgery was performed after one week. Proximal perforator was clamped and ligated after checking adequate perfusion of flap. Flap was insetted into defect. Results:Thirty-two patients were reconstructed with delayed reverse sural artery flap. The mean age of the patients was 26.5 +12.2 years. Twenty-four (75%) patients were males and 8 (25%) were females. Twenty-two (68.7%) cases were degloving wounds after road traffic accidents (RTA), 6 (18.7%) were diabetic foot wounds, 4 (12.5%) sustained injury after falling from height and 7 (21.8%) patients had fracture of metatarsals. Twenty-eight flaps were transferred after one week delay, and only in 4 cases, flap were transferred after two weeks. All flaps survived completely. Complications of infection noted in 3 (9.3%) flaps, 3 (9.3%) flaps showed tip necrosis, 2 (6.2%) flaps undergone epidermolysis and only 2 (6.2%) showed venous congestion. Conclusion:Delayed islanded reverse sural artery perforator flap is a reliable and versatile option for resurfacing soft tissue defects of lower limb proximal to the toes with lesser complications and extended coverage area. (author)

  15. Extended Islanded Reverse Sural Artery flap for Staged Reconstruction of Foot Defects Proximal to Toes.

    Science.gov (United States)

    Yousaf, Muhammad Amin; Abidin, Zain Ul; Khalid, Kamran; Haq, Ata Ul; Khalid, Farrukh Aslam; Tarar, Faraz Ahmad; Asif, Muhammad Umar; Tarar, Moazzam Nazeer

    2018-02-01

    Obective:To assess the outcome of extended delayed reverse sural artery flap for reconstruction of foot defects proximal to toes in terms of flap survival, complication and extended area. Case series. Jinnah Burn and Reconstructive Surgery Centre, Lahore, from February 2015 to April 2017. Cases who underwent delayed sural artery flap were inducted. Preoperative hand-held doppler was done to confirm the location of perforator. Two suitable perforators were chosen to raise the extended flap by crossing the proximal limit in all cases. The pedicle was kept minimum 3 cm wide and perfusion was assessed. Flap was delayed for one week and vaccum-assisted closure (VAC) dressing was applied over wound. The second surgery was performed after one week. Proximal perforator was clamped and ligated after checking adequate perfusion of flap. Flap was insetted into defect. Thirty-two patients were reconstructed with delayed reverse sural artery flap. The mean age of the patients was 26.5 12.2 years. Twenty-four (75%) patients were males and 8 (25%) were females. Twenty-two (68.7%) cases were degloving wounds after road traffic accidents (RTA), 6 (18.7%) were diabetic foot wounds, 4 (12.5%) sustained injury after falling from height and 7 (21.8%) patients had fracture of metatarsals. Twenty-eight flaps were transferred after one week delay, and only in 4 cases, flap were transferred after two weeks. All flaps survived completely. Complications of infection noted in 3 (9.3%) flaps, 3 (9.3%) flaps showed tip necrosis, 2 (6.2%) flaps undergone epidermolysis and only 2 (6.2%) showed venous congestion. Delayed islanded reverse sural artery perforator flap is a reliable and versatile option for resurfacing soft tissue defects of lower limb proximal to the toes with lesser complications and extended coverage area.

  16. [Are Visual Field Defects Reversible? - Visual Rehabilitation with Brains].

    Science.gov (United States)

    Sabel, B A

    2017-02-01

    local activation of the visual cortex and global reorganisation of neuronal brain networks. Because modulation of neuroplasticity can strengthen residual vision, the brain deserves a better reputation in ophthalmology for its role in visual rehabilitation. For patients, there is now more light at the end of the tunnel, because vision loss in some areas of the visual field defect is indeed reversible. Georg Thieme Verlag KG Stuttgart · New York.

  17. Defect thiospinels: a new class of reversible cathode material

    Science.gov (United States)

    James, A. C. W. P.; Goodenough, J. B.

    1989-05-01

    The defect thiospinel Cu 0.07[Ti 2]S 4 was prepared by low-temperature oxidative extraction of copper from Cu[Ti 2]S 4. Up to two equivalents of lithium can be inserted into Cu 0.07[Ti 2]S 4 reversibly with fast electrochemical kinetics at room temperature; the defect thiospinel is, therefore, a highly promising alternative to layered TiS 2 as a cathode material for lithium secondary batteries. Samples of Cu 1- x [Ti 2]S 4 (0⩽ x ⩽ 0.93) and Li xCu 0.07[Ti 2]S 4 (0 < x < 2) were prepared and characterised by 65Cu and 7Li solid-state NMR, neutron powder diffraction, and electrochemical measurements. Cu 0.07[Ti 2]S 4 is a semimetal with the residual copper located on the normal spinel A-cation sites. The lithium in Li xCu 0.07[Ti 2]S 4 is located only in the 16c octahedral sites of the spinel framework at all lithium compositions. The open-circuit voltage of Li xCu 0.07[Ti 2]S 4versus lithium metal is nearly identical to that of layered Li xTiS 2 over the whole lithium-composition range. The chemical diffusion constant of lithium in Li xCu 0.07[Ti 2]S 4 (0.5 ⩽ x⩽ 1.5) was found to be 1 × 10 -9 cm 2 s -1, which is comparable with that in layered Li xTiS 2.

  18. The reverse sural artery fasciomusculocutaneous flap for small lower-limb defects: the use of the gastrocnemius muscle cuff as a plug for small bony defects following debridement of infected/necrotic bone.

    Science.gov (United States)

    Al-Qattan, M M

    2007-09-01

    The reverse sural artery fasciomusculocutaneous flap is a modification of the original fasciocutaneous flap in which a midline gastrocnemius muscle cuff around the buried sural pedicle is included in the flap. This modification was done to improve the blood supply of the distal part of the flap, which is harvested from the upper leg. The aim of this paper is to demonstrate that there is another important advantage of the modified flap: the use of the muscle cuff as a "plug" for small lower limb defects following debridement of infected/necrotic bone. A total of 10 male adult patients with small complex lower-limb defects with underlying bone pathology were treated with the modified flap using the muscle component to fill up the small bony defects. The bony pathology included necrotic exposed bone without evidence of osteomyelitis or wound infection (n = 1), an underlying neglected tibial fracture with wound infection (n = 4), and a sinus at the heel with underlying calcaneal osteomyelitis (n = 5). Primary wound healing of the flap into the defect was noted in all patients. No recurrence of calcaneal osteomyelitis was seen and all tibial fractures united following appropriate orthopedic fixation. It was concluded that the reverse sural artery fasciomusculocutaneous flap is well suited for small complex lower-limb defects with underlying bone pathology.

  19. Influence of defect size and localization on the engagement of reverse Hill-Sachs lesions.

    Science.gov (United States)

    Moroder, Philipp; Runer, Armin; Kraemer, Manuel; Fierlbeck, Johann; Niederberger, Alfred; Cotofana, Sebastian; Vasvari, Imre; Hettegger, Bernhard; Tauber, Mark; Hurschler, Christof; Resch, Herbert

    2015-03-01

    Reverse Hill-Sachs (RHS) lesions can cause recurrent posterior shoulder instability because of engagement with the posterior glenoid rim; however, the effect of defect size and localization have yet to be determined. Both size and localization are critical for the engagement of an RHS defect with the posterior glenoid rim. Controlled laboratory study. Ten RHS defects with predefined extent and localization were created through an anterolateral rotator cuff sparing approach in 10 fresh-frozen cadaveric shoulder specimens using a custom-made saw guide. Computed tomography scans of all specimens were completed, and standardized measurements were performed to determine the size (alpha angle) and localization (beta angle) of the defect as well as a combination of both parameters (gamma angle). Internal rotation motions were imposed on the shoulder joint in different arm positions and with varying amount of posterior translation by means of a robot-assisted shoulder simulator. The association between engagement of the defects and the defined parameters (alpha, beta, and gamma angles) was analyzed. In 0° of abduction, a cutoff value between engaging and nonengaging defects of 37.5° for the alpha angle (100% sensitivity; 75% specificity; area under the curve [AUC], 0.875; P = .055) and 36.5° for the beta angle (100% sensitivity; 25% specificity; AUC, 0.708; P = .286) was determined. The gamma angle showed the highest discriminatory power (AUC, 0.938; P = .025) with a cutoff value of 85.5° rendering 100% sensitivity and 75% specificity in the prediction of engagement. An increase in the applied posterior translation force decreased the degrees of internal rotation necessary before engagement occurred. No engagement occurred during internal rotation with the arm in 60° of abduction or 60° of flexion. The size and localization of RHS defects are both critical factors for engagement. The combination of both parameters in terms of the gamma angle measurement might be a

  20. Defect mediated reversible ferromagnetism in Co and Mn doped zinc oxide epitaxial films

    Energy Technology Data Exchange (ETDEWEB)

    Mal, Siddhartha; Nori, Sudhakar; Narayan, J. [Department of Material Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Mula, Suhrit [Department of Material Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Department of Metallurgical and Materials Engineering, National Institute of Technology, Rourkela 769008 (India); Prater, J. T. [Materials Science Division, Army Research Office, Research Triangle Park, North Carolina 27709 (United States)

    2012-12-01

    We have introduced defects in ZnO (undoped and doped with Co and Mn) epitaxial thin films using laser irradiation from nanosecond laser pulses and thermal annealing in oxygen ambient. In contrast to the as grown samples, the laser irradiated films show a significant increase in conductivity, enhancement in UV emission, while maintaining the same wurtzite crystal structure. Room-temperature ferromagnetism (RTFM) is observed in laser-irradiated samples, which increased with the number of laser pulses up to a certain value where magnetic moment saturates. The induced ferromagnetism as well as the enhanced electrical conductivity can be reversed with thermal annealing in oxygen ambient. The magnetization in Co and Mn doped films was found to be strong function of growth conditions and defect concentration. X-ray diffraction and optical absorption experiments suggested a 2+ valance state and tetrahedral coordination for both Co and Mn ions. There is a simultaneous increase in n-type electrical conductivity with the number of laser pulses and continue to exhibit semiconducting behavior in both undoped and doped films. The saturation magnetization was found to be 0.08 {mu}{sub B}/Co and 0.05 {mu}{sub B}/Mn, much lower than 3.0 {mu}{sub B}/Co and 5.0 {mu}{sub B}/Mn, indicating the prominent role of intrinsic defects in RTFM with some contribution from Co{sup 2+}-oxygen vacancy complexes. We propose a unified mechanism based upon introduction of intrinsic defects to explain RTFM and n-type conductivity enhancements during pulsed laser and thermal annealing.

  1. Reversibility of Defective Hematopoiesis Caused by Telomere Shortening in Telomerase Knockout Mice.

    Directory of Open Access Journals (Sweden)

    Aparna Raval

    Full Text Available Telomere shortening is common in bone marrow failure syndromes such as dyskeratosis congenita (DC, aplastic anemia (AA and myelodysplastic syndromes (MDS. However, improved knowledge of the lineage-specific consequences of telomere erosion and restoration of telomere length in hematopoietic progenitors is required to advance therapeutic approaches. We have employed a reversible murine model of telomerase deficiency to compare the dependence of erythroid and myeloid lineage differentiation on telomerase activity. Fifth generation Tert-/- (G5 Tert-/- mice with shortened telomeres have significant anemia, decreased erythroblasts and reduced hematopoietic stem cell (HSC populations associated with neutrophilia and increased myelopoiesis. Intracellular multiparameter analysis by mass cytometry showed significantly reduced cell proliferation and increased sensitivity to activation of DNA damage checkpoints in erythroid progenitors and in erythroid-biased CD150hi HSC, but not in myeloid progenitors. Strikingly, Cre-inducible reactivation of telomerase activity restored hematopoietic stem and progenitor cell (HSPC proliferation, normalized the DNA damage response, and improved red cell production and hemoglobin levels. These data establish a direct link between the loss of TERT activity, telomere shortening and defective erythropoiesis and suggest that novel strategies to restore telomerase function may have an important role in the treatment of the resulting anemia.

  2. Upward creep of the heart: A frequent source of false-positive reversible defects during thallium-201 stress-redistribution SPECT

    International Nuclear Information System (INIS)

    Friedman, J.; Van Train, K.; Maddahi, J.; Rozanski, A.; Prigent, F.; Bietendorf, J.; Waxman, A.; Berman, D.S.

    1989-01-01

    A new cause of artifactual 201 Tl defects on single photon emission computed tomography (SPECT) termed upward creep of the heart is described. In 102 consecutive patients undergoing 201 Tl SPECT, 30 (29%) demonstrated upward creep defined by an upward movement of the heart of greater than or equal to 2 pixels during acquisition. In 45 consecutive patients with a less than 5% likelihood of coronary artery disease, 17 (38%) had upward creep. Of these nine had reversible 201 Tl defects localized to the inferior and basal inferoseptal walls, while none of the 28 without upward creep had defects. The 17 low likelihood patients with upward creep had longer exercise duration and higher peak heart rate than those without upward creep. In five additional low likelihood patients with upward creep in whom imaging was immediately repeated, the upward creep pattern disappeared on the repeated images. After we changed our test protocol to begin imaging 15 min postexercise, only five (14%) of 36 low likelihood patients tested demonstrated upward creep. Upward creep is probably related to a transient increase in mean total lung volume early following exhaustive exercise, resulting in a mean lower position of the diaphragm (and thus the heart) at the beginning of imaging. The frequency of this source of false-positive 201 Tl studies can be reduced by delaying SPECT acquisition until 15 min postexercise

  3. Reconstruction of hand contracture by reverse ulnar perforator flap

    Directory of Open Access Journals (Sweden)

    Cengiz Eser

    2016-04-01

    Full Text Available Hand burn scar contractures affect patients in aesthetic and functional aspects. After releasing these scars, the defects should be repaired. The reconstruction methods include primary suturation, Z plasty, skin grafting, local or free flaps, etc. All methods have their own advantages and disadvantages. One of the most useful flaps is the reverse ulnar perforator flap. We performed a two-staged procedure for repairing a post-burn contracture release defect in a 40-year-old male. In the first stage we applied reverse ulnar perforator flap for the hand defect, and ulnar artery and vein repair in the second stage. In conclusion, this two-staged procedure is a non-primary but useful option for hand and finger defects and prevents major vascular structure damage of the forearm. [Hand Microsurg 2016; 5(1.000: 40-43

  4. Defect engineering of ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Weber, M.H. [Center for Materials Research and Department of Physics and Astronomy, Washington State University, Pullman, WA 99164-2711 (United States)], E-mail: m_weber@wsu.edu; Selim, F.A.; Solodovnikov, D.; Lynn, K.G. [Center for Materials Research and Department of Physics and Astronomy, Washington State University, Pullman, WA 99164-2711 (United States)

    2008-10-31

    The defect responsible for the transparent to red color change of nominally undoped ZnO bulk single crystals is investigated. Upon annealing in the presence of metallic Zn as reported by Halliburton et al. and also Ti and Zr a native defect forms with an energy level about 0.7 eV below the conduction band. This change is reversible upon annealing in oxygen. Optical transmission data along with positron depth profiles and annealing studies are combined to identify the defect as oxygen vacancies. Vacancy clustering occurs at about 500 deg. C if isolated zinc and oxygen vacancies. In the absence of zinc vacancies, clusters form at about 800 deg. C.

  5. Defect engineering of ZnO

    International Nuclear Information System (INIS)

    Weber, M.H.; Selim, F.A.; Solodovnikov, D.; Lynn, K.G.

    2008-01-01

    The defect responsible for the transparent to red color change of nominally undoped ZnO bulk single crystals is investigated. Upon annealing in the presence of metallic Zn as reported by Halliburton et al. and also Ti and Zr a native defect forms with an energy level about 0.7 eV below the conduction band. This change is reversible upon annealing in oxygen. Optical transmission data along with positron depth profiles and annealing studies are combined to identify the defect as oxygen vacancies. Vacancy clustering occurs at about 500 deg. C if isolated zinc and oxygen vacancies. In the absence of zinc vacancies, clusters form at about 800 deg. C

  6. Third-party Reverse logistics platform and method Based on Bilateral Resource Integration

    Directory of Open Access Journals (Sweden)

    Zheng Hong Zhen

    2016-01-01

    Full Text Available Dispersion of reverse logistics resources makes it difficult to create relationships between demanders and providers, thereby the personalized demand for the construction of enterprise reverse logistics cannot be satisfied and the service quality cannot be guaranteed. Aiming at these problems, this paper presents a platform and method of enterprise reverse logistics based on bilateral resource integration (RLBRI. The method creates a third-party reverse logistics platform to accumulate a mass of reverse logistics demanders and providers together. And the platform integrates bilateral resources and acts as an intermediary to establish relationships between two sides. Through the platform, a complete and high-quality business chain for enterprise reverse logistics will be built efficiently. Finally put forward an effective strategy of non-defective reverse logistics depends on the integrity checking service provided by third-party logistics. By using this strategy it can short the distance of non-defective reverse transportation. Computational tests validate the strategy.

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

    Science.gov (United States)

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

    2012-01-01

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

  8. Airways obstruction in survivors of thoracoplasty: reversibility is greater in non-smokers.

    LENUS (Irish Health Repository)

    O'Connor, Terence M

    2012-02-03

    OBJECTIVE: Before the advent of antituberculous chemotherapy, thoracoplasty (TPL) was the definitive form of therapy for cavitary pulmonary tuberculosis. This study aimed to characterize the late functional sequelae of TPL, and to establish the degree of reversibility of any consequent airway obstruction. METHODOLOGY: Pulmonary function was studied in 21 long-term (mean 35 years) survivors of TPL between the years 1990-2001. RESULTS: A mixed obstructive\\/restrictive defect was found in this patient cohort. After inhalation of bronchodilator, marginal increases in FEV(1) and FVC and marginal decreases in FRC, RV and TLC were observed. Maximum mid-expiratory flow rate was severely reduced (28.8% of predicted), but reversibility after inhaled beta(2)-agonist was highest for this parameter of pulmonary function (mean 11%). Smokers had a higher RV (P = 0.04), suggesting hyperinflation, while non-smokers had a larger increase in FEV(1)\\/FVC ratio postbronchodilator (P = 0.004), suggesting more marked reversibility of airways obstruction in this group. CONCLUSIONS: Long-term survivors of TPL have an obstructive as well as a restrictive ventilatory defect. These patients have partial reversibility of the obstructive defect. The degree of reversibility found suggests that bronchodilator therapy may help these patients.

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

    Science.gov (United States)

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

    2016-07-08

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

  10. Formation and biochemical characterization of tube/pelle death domain complexes: critical regulators of postreceptor signaling by the Drosophila toll receptor.

    Science.gov (United States)

    Schiffmann, D A; White, J H; Cooper, A; Nutley, M A; Harding, S E; Jumel, K; Solari, R; Ray, K P; Gay, N J

    1999-09-07

    In Drosophila, the Toll receptor signaling pathway is required for embryonic dorso-ventral patterning and at later developmental stages for innate immune responses. It is thought that dimerization of the receptor by binding of the ligand spätzle causes the formation of a postreceptor activation complex at the cytoplasmic surface of the membrane. Two components of this complex are the adaptor tube and protein kinase pelle. These proteins both have "death domains", protein interaction motifs found in a number of signaling pathways, particularly those involved in apoptotic cell death. It is thought that pelle is bound by tube during formation of the activation complexes, and that this interaction is mediated by the death domains. In this paper, we show using the yeast two-hybrid system that the wild-type tube and pelle death domains bind together. Mutant tube proteins which do not support signaling in the embryo are also unable to bind pelle in the 2-hybrid assay. We have purified proteins corresponding to the death domains of tube and pelle and show that these form corresponding heterodimeric complexes in vitro. Partial proteolysis reveals a smaller core consisting of the minimal death domain sequences. We have studied the tube/pelle interaction with the techniques of surface plasmon resonance, analytical ultracentrifugation and isothermal titration calorimetry. These measurements produce a value of K(d) for the complex of about 0.5 microM.

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

    Directory of Open Access Journals (Sweden)

    Sandra Almeida

    2012-10-01

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

  12. Pathogenesis of Insulin Resistance in Skeletal Muscle

    Directory of Open Access Journals (Sweden)

    Muhammad A. Abdul-Ghani

    2010-01-01

    Full Text Available Insulin resistance in skeletal muscle is manifested by decreased insulin-stimulated glucose uptake and results from impaired insulin signaling and multiple post-receptor intracellular defects including impaired glucose transport, glucose phosphorylation, and reduced glucose oxidation and glycogen synthesis. Insulin resistance is a core defect in type 2 diabetes, it is also associated with obesity and the metabolic syndrome. Dysregulation of fatty acid metabolism plays a pivotal role in the pathogenesis of insulin resistance in skeletal muscle. Recent studies have reported a mitochondrial defect in oxidative phosphorylation in skeletal muscle in variety of insulin resistant states. In this review, we summarize the cellular and molecular defects that contribute to the development of insulin resistance in skeletal muscle.

  13. Cytoskeletal defects in Bmpr2-associated pulmonary arterial hypertension.

    Science.gov (United States)

    Johnson, Jennifer A; Hemnes, Anna R; Perrien, Daniel S; Schuster, Manfred; Robinson, Linda J; Gladson, Santhi; Loibner, Hans; Bai, Susan; Blackwell, Tom R; Tada, Yuji; Harral, Julie W; Talati, Megha; Lane, Kirk B; Fagan, Karen A; West, James

    2012-03-01

    The heritable form of pulmonary arterial hypertension (PAH) is typically caused by a mutation in bone morphogenic protein receptor type 2 (BMPR2), and mice expressing Bmpr2 mutations develop PAH with features similar to human disease. BMPR2 is known to interact with the cytoskeleton, and human array studies in PAH patients confirm alterations in cytoskeletal pathways. The goal of this study was to evaluate cytoskeletal defects in BMPR2-associated PAH. Expression arrays on our Bmpr2 mutant mouse lungs revealed cytoskeletal defects as a prominent molecular consequence of universal expression of a Bmpr2 mutation (Rosa26-Bmpr2(R899X)). Pulmonary microvascular endothelial cells cultured from these mice have histological and functional cytoskeletal defects. Stable transfection of different BMPR2 mutations into pulmonary microvascular endothelial cells revealed that cytoskeletal defects are common to multiple BMPR2 mutations and are associated with activation of the Rho GTPase, Rac1. Rac1 defects are corrected in cell culture and in vivo through administration of exogenous recombinant human angiotensin-converting enzyme 2 (rhACE2). rhACE2 reverses 77% of gene expression changes in Rosa26-Bmpr2(R899X) transgenic mice, in particular, correcting defects in cytoskeletal function. Administration of rhACE2 to Rosa26-Bmpr2(R899X) mice with established PAH normalizes pulmonary pressures. Together, these findings suggest that cytoskeletal function is central to the development of BMPR2-associated PAH and that intervention against cytoskeletal defects may reverse established disease.

  14. Added Value of 3D Cardiac SPECT/CTA Fusion Imaging in Patients with Reversible Perfusion Defect on Myocardial Perfusion SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Eun Jung; Cho, Ihn Ho [Yeungnam University Hospital, Daegu (Korea, Republic of); Kang, Won Jun [Yonsei University Hospital, Seoul (Korea, Republic of); Kim, Seong Min [Chungnam National University Medical School and Hospital, Daejeon (Korea, Republic of); Won, Kyoung Sook [Keomyung University Dongsan Hospital, Daegu (Korea, Republic of); Lim, Seok Tae [Chonbuk National University Medical School and Hospital, Jeonju (Korea, Republic of); Hwang, Kyung Hoon [Gachon University Gil Hospital, Incheon (Korea, Republic of); Lee, Byeong Il; Bom, Hee Seung [Chonnam National University Medical School and Hospital, Gwangju (Korea, Republic of)

    2009-12-15

    Integration of the functional information of myocardial perfusion SPECT (MPS) and the morphoanatomical information of coronary CT angiography (CTA) may provide useful additional diagnostic information of the spatial relationship between perfusion defects and coronary stenosis. We studied to know the added value of three dimensional cardiac SPECT/CTA fusion imaging (fusion image) by comparing between fusion image and MPS. Forty-eight patients (M:F=26:22, Age: 63.3{+-}10.4 years) with a reversible perfusion defect on MPS (adenosine stress/rest SPECT with Tc-99m sestamibi or tetrofosmin) and CTA were included. Fusion images were molded and compared with the findings from the MPS. Invasive coronary angiography served as a reference standard for fusion image and MPS. Total 144 coronary arteries in 48 patients were analyzed; Fusion image yielded the sensitivity, specificity, negative and positive predictive value for the detection of hemodynamically significant stenosis per coronary artery 82.5%, 79.3%, 76.7% and 84.6%, respectively. Respective values for the MPS were 68.8%, 70.7%, 62.1% and 76.4%. And fusion image also could detect more multi-vessel disease. Fused three dimensional volume-rendered SPECT/CTA imaging provides intuitive convincing information about hemodynamic relevant lesion and could improved diagnostic accuracy.

  15. Pattern-reversal electroretinograms in unilateral glaucoma.

    Science.gov (United States)

    Wanger, P; Persson, H E

    1983-06-01

    Pattern-reversal and flash electroretinograms (ERG) and oscillatory potentials (OP) were recorded from 11 patients with unilateral glaucoma. All glaucomatous eyes had reduced amplitudes both compared to the opposite eye in the same patient and to reference values. In 10 of the 11 cases this reduction was below the level of normal variation. The difference in pattern-reversal ERG amplitude means from glaucomatous and opposite eyes was statistically significant. No differences were observed in flash ERGs or OPs. The histopathologic correlate to the visual field defects in glaucoma is retinal ganglion cell degeneration. The present electrophysiologic findings support the view, based on results from animal experiments, that the pattern-reversal ERG reflects ganglion cell activity.

  16. Hybrid Algorithms for Fuzzy Reverse Supply Chain Network Design

    Science.gov (United States)

    Che, Z. H.; Chiang, Tzu-An; Kuo, Y. C.

    2014-01-01

    In consideration of capacity constraints, fuzzy defect ratio, and fuzzy transport loss ratio, this paper attempted to establish an optimized decision model for production planning and distribution of a multiphase, multiproduct reverse supply chain, which addresses defects returned to original manufacturers, and in addition, develops hybrid algorithms such as Particle Swarm Optimization-Genetic Algorithm (PSO-GA), Genetic Algorithm-Simulated Annealing (GA-SA), and Particle Swarm Optimization-Simulated Annealing (PSO-SA) for solving the optimized model. During a case study of a multi-phase, multi-product reverse supply chain network, this paper explained the suitability of the optimized decision model and the applicability of the algorithms. Finally, the hybrid algorithms showed excellent solving capability when compared with original GA and PSO methods. PMID:24892057

  17. Reverse redistribution of thallium-201: a sign of nontransmural myocardial infarction with patency of the infarct-related coronary artery

    International Nuclear Information System (INIS)

    Weiss, A.T.; Maddahi, J.; Lew, A.S.; Shah, P.K.; Ganz, W.; Swan, H.J.; Berman, D.S.

    1986-01-01

    The pattern of reverse redistribution on the day 10 poststreptokinase resting thallium-201 myocardial scintigrams is a common finding in patients who have undergone streptokinase therapy in evolving myocardial infarction. To investigate this phenomenon, 67 patients who underwent streptokinase therapy were studied pre- and 10 days poststreptokinase therapy resting thallium-201 studies, poststreptokinase therapy resting radionuclide ventriculography and coronary arteriography (60 of the 67 patients). Of the 67 patients, 50 (75%) showed the reverse redistribution pattern on the day 10 thallium-201 study (Group I), 9 (13%) had a nonreversible defect (Group II) and the remaining 8 (12%) had a normal study or showed a reversible defect (Group III). The reverse redistribution pattern was associated with patency of the infarct-related artery (100%), quantitative improvement in resting thallium-201 defect size from day 1 to day 10 study (94%) and normal or near normal wall motion on day 10 radionuclide ventriculography (80% of segments with marked and 54% of those with mild reverse redistribution). In contrast, nonreversible defects were associated with significantly less frequent patency of the infarct-related artery (67%, p = 0.01), improvement in defect size (11%, p less than 0.001) and normal or near normal wall motion (21%, p less than 0.05). Group III patients were similar to Group I with respect to these variables. The quantitated thallium-201 percent washout was higher in the regions with the reverse redistribution pattern (49 +/- 15%) compared with the contralateral normal zone (24 +/- 15%, p less than 0.001)

  18. Posterior Reversible Encephalopathy (PRES)

    International Nuclear Information System (INIS)

    Moron E, Fanny E; Diaz Marchan, Pedro

    2005-01-01

    The Posterior Reversible Encephalopathy Syndrome (PRES) is a clinical Syndrome composed of cephalea, alteration in vision and convulsions, usually observed in patients with sudden elevation of arterial pressure. The imagenologic evidence shows reversible vasogenic brain edema without stroke. Its location is predominantly posterior; it affects the cortex and the subcortical white matter of the occipital, parietal and temporal lobes. The treatment with antihypertensive drugs and the removing of immunosupressor medication are generally associated with complete neurological recovery; this is reflected also in the images which return to their basal condition. The untreated hypertension, on the other side, can result in a progressive defect of the autoregulation system of the central nervous system with cerebral hemorrhage, irreversible brain stroke, coma and death

  19. THYROID HORMONE REVERSES AGING-INDUCED MYOCARDIAL FATTY ACID OXIDATION DEFECTS AND IMPROVES THE RESPONSE TO ACUTELY INCREASED AFTERLOAD

    Energy Technology Data Exchange (ETDEWEB)

    Ledee, Dolena; Portman, Michael A.; Kajimoto, Masaki; Isern, Nancy G.; Olson, Aaron

    2013-06-07

    Background: Subclinical hypothyroidism occurs during aging in humans and mice and may contribute to development of heart failure. Aging also impairs myocardial fatty acid oxidation, causing increased reliance on flux through pyruvate dehydrogenase (PDH) to maintain function. We hypothesize that the metabolic changes in aged hearts make them less tolerant to acutely increased work and that thyroid hormone reverses these defects. Methods: Studies were performed on young (Young, 4-6 months) and aged (Old, 22-24 months) C57/BL6 mice at standard (50 mmHg) and high afterload (80 mmHg). Another aged group received thyroid hormone for 3 weeks (Old-TH, high afterload only). Function was measured in isolated working hearts along with substrate fractional contributions (Fc) to the citric acid cycle (CAC) using perfusate with 13C labeled lactate, pyruvate, glucose and unlabeled palmitate and insulin. Results: Cardiac function was similar between Young and Old mice at standard afterload. Palmitate Fc was reduced but no individual carbohydrate contributions differed. CAC and individual substrate fluxes decreased in aged. At high afterload, -dP/dT was decreased in Old versus Young. Similar to low afterload, palmitate Fc was decreased in Old. Thyroid hormone reversed aging-induced changes in palmitate Fc and flux while significantly improving cardiac function. Conclusion: The aged heart shows diminished ability to increase cardiac work due to substrate limitations, primarily impaired fatty acid oxidation. The heart accommodates slightly by increasing efficiency through oxidation of carbohydrate substrates. Thyroid hormone supplementation in aged mice significantly improves cardiac function potentially through restoration of fatty acid oxidation.

  20. Absence of down-regulation of the insulin receptor by insulin. A possible mechanism of insulin resistance in the rat.

    OpenAIRE

    Walker, A P; Flint, D J

    1983-01-01

    Insulin resistance occurs in rat adipocytes during pregnancy and lactation despite increased or normal insulin binding respectively; this suggests that a post-receptor defect exists. The possibility has been examined that, although insulin binding occurs normally, internalization of insulin or its receptor may be impaired in these states. Insulin produced a dose-dependent reduction in the number of insulin receptors on adipocytes from virgin rats maintained in culture medium, probably due to ...

  1. Facile synthesis and electrochemical properties of continuous porous spheres assembled from defect-rich, interlayer-expanded, and few-layered MoS2/C nanosheets for reversible lithium storage

    Science.gov (United States)

    Chen, Biao; Lu, Huihui; Zhao, Naiqin; Shi, Chunsheng; Liu, Enzuo; He, Chunnian; Ma, Liying

    2018-05-01

    Hollow or continuous porous hierarchical MoS2/C structures with large Li-ion and electron transport kinetics, and high structural stability are urgent needs for their application in lithium ion batteries. In this regard, a novel continuous porous micro-sphere constructed from defect-rich, interlayer-expanded, and few-layered MoS2/C nanosheets is successfully synthesized through a facile one-pot hydrothermal method. The polyvinyl pyrrolidone surfactant serves as carbon source and supporter, while the CS2 works as soft template and sulfur source during hydrothermal process. The morphologies, structures, and electrochemical properties are systematically characterized. Importantly, it should be noted that the unique porous micro-spheres with merits of rich-defect, expanded-interlayer, few-layer (integrating carbon are favorable for lithium ion batteries application. When the uniform composites are used as lithium ion batteries anode materials, they deliver a high reversible capacity, excellent cycling performance (average capacity fading of 0.037% per cycle at 0.2 A g-1), and good rate capability.

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

    International Nuclear Information System (INIS)

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

    2005-01-01

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

  3. The role of bulk and interface states on performance of a-Si: H p-i-n solar cells using reverse current-voltage technique

    International Nuclear Information System (INIS)

    Mahmood, S A; Kabir, M Z; Murthy, R V R; Dutta, V

    2009-01-01

    The defect state densities in the bulk of the i-layer and at the p/i interface have been studied in hydrogenated amorphous silicon (a-Si : H) solar cells using reverse current-voltage (J-V) measurements. In this work the cells have been soaked with blue and red lights prior to measurements. The voltage-dependent reverse current has been analysed on the basis of thermal generation of the carriers from midgap states in the i-layer and the carrier injection through the p/i interface. Based on the reverse current behaviour, it has been analysed that at lower reverse bias (reverse voltage, V r r ∼ 25 V) the defect states at the p/i interface are contributing to the reverse currents. The applied reverse bias annealing (RBA) treatment on these cells shows more significant annihilation of defect states at the p/i interface as compared with the bulk of the i-layer. An analytical model is developed to explain the observed behaviour. There is good agreement between the theory and the experimental observations. The fitted defect state densities are 9.1 x 10 15 cm -3 and 8 x 10 18 cm -3 in the bulk of the i-layer and near the p/i interface, respectively. These values decrease to 2.5 x 10 15 cm -3 and 6 x 10 17 cm -3 , respectively, in the samples annealed under reverse bias at 2 V.

  4. Reverse (posterior) cloaca with congenital rectal stenosis and pseudohermaphrodism: a rare entity with rare association

    Science.gov (United States)

    Ahmed, Intezar; Kureel, Shiv Narain; Chandra, Naveen

    2010-01-01

    Reverse (posterior) cloaca is itself a rare entity and association of this defect with other congenital syndromes or defects is extremely rare to find. To diagnose this unique anomaly one should be aware about this very infrequently encountered clinical entity. Reverse cloaca is a very rare variant of anorectal malformation in which urethra and vagina fused to form a urogenital sinus that diverts posteriorly and opens in the anterior rectal wall at the anus or immediately anterior to it. We report a neonate with the rare clinical entity of reverse cloaca type C, pseudophallus with rudimentary urethra as a component of female pseudohermaphrodism and congenital rectal stenosis. Surprisingly, there was no associated urological abnormality on ultrasonography and laparotomy. PMID:22797480

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-05-01

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

  6. Application of reverse engineering in the medical industry.

    Science.gov (United States)

    Kaleev, A. A.; Kashapov, L. N.; Kashapov, N. F.; Kashapov, R. N.

    2017-09-01

    The purpose of this research is to develop on the basis of existing analogs new design of ophthalmologic microsurgical tweezers by using reverse engineering techniques. Virtual model was obtained by using a three-dimensional scanning system Solutionix Rexcan 450 MP. Geomagic Studio program was used to remove defects and inaccuracies of the obtained parametric model. A prototype of the finished model was made on the installation of laser stereolithography Projet 6000. Total time of the creation was 16 hours from the reverse engineering procedure to 3D-printing of the prototype.

  7. Light-induced defects in hybrid lead halide perovskite

    Science.gov (United States)

    Sharia, Onise; Schneider, William

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

  8. Reverse Saphenous Conduit Flap in 19 Dogs and 1 Cat.

    Science.gov (United States)

    Cavalcanti, Jacqueline V J; Barry, Sabrina L; Lanz, Otto I; Barnes, Katherine; Coutin, Julia V

    2018-05-14

    The purpose of this retrospective study was to report the outcomes of 19 dogs and 1 cat undergoing reverse saphenous conduit flap between 1999 and 2016. Reverse saphenous conduit flap was used to treat traumatic wounds and wounds resulting from tumor excision in the hind limb; the majority of cases had medial shearing injuries. All animals had complete flap survival. In five animals (20%), minor donor site dehiscence occurred, which did not require surgery. Other postoperative complications included signs of severe venous congestion in one dog. Reverse saphenous conduit flap is a useful technique to repair skin defects of the distal hind limb.

  9. Similarities between long interspersed element-1 (LINE-1) reverse transcriptase and telomerase.

    Science.gov (United States)

    Kopera, Huira C; Moldovan, John B; Morrish, Tammy A; Garcia-Perez, Jose Luis; Moran, John V

    2011-12-20

    Long interspersed element-1 (LINE-1 or L1) retrotransposons encode two proteins (ORF1p and ORF2p) that contain activities required for conventional retrotransposition by a mechanism termed target-site primed reverse transcription. Previous experiments in XRCC4 or DNA protein kinase catalytic subunit-deficient CHO cell lines, which are defective for the nonhomologous end-joining DNA repair pathway, revealed an alternative endonuclease-independent (ENi) pathway for L1 retrotransposition. Interestingly, some ENi retrotransposition events in DNA protein kinase catalytic subunit-deficient cells are targeted to dysfunctional telomeres. Here we used an in vitro assay to detect L1 reverse transcriptase activity to demonstrate that wild-type or endonuclease-defective L1 ribonucleoprotein particles can use oligonucleotide adapters that mimic telomeric ends as primers to initiate the reverse transcription of L1 mRNA. Importantly, these ribonucleoprotein particles also contain a nuclease activity that can process the oligonucleotide adapters before the initiation of reverse transcription. Finally, we demonstrate that ORF1p is not strictly required for ENi retrotransposition at dysfunctional telomeres. Thus, these data further highlight similarities between the mechanism of ENi L1 retrotransposition and telomerase.

  10. Angular dependence of magnetization reversal in epitaxial chromium telluride thin films with perpendicular magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Pramanik, Tanmoy, E-mail: pramanik.tanmoy@utexas.edu; Roy, Anupam, E-mail: anupam@austin.utexas.edu; Dey, Rik, E-mail: rikdey@utexas.edu; Rai, Amritesh; Guchhait, Samaresh; Movva, Hema C.P.; Hsieh, Cheng-Chih; Banerjee, Sanjay K.

    2017-09-01

    Highlights: • Perpendicular magnetic anisotropy in epitaxial Cr{sub 2}Te{sub 3} has been investigated. • Presence of a relatively strong second order anisotropy contribution is observed. • Magnetization reversal is explained quantitatively using a 1D defect model. • Relative roles of nucleation and pinning in magnetization reversal are discussed. • Domain structures and switching process are visualized by micromagnetic simulation. - Abstract: We investigate magnetic anisotropy and magnetization reversal mechanism in chromium telluride thin films grown by molecular beam epitaxy. We report existence of strong perpendicular magnetic anisotropy in these thin films, along with a relatively strong second order anisotropy contribution. The angular variation of the switching field observed from the magnetoresistance measurement is explained quantitatively using a one-dimensional defect model. The model reveals the relative roles of nucleation and pinning in the magnetization reversal, depending on the applied field orientation. Micromagnetic simulations are performed to visualize the domain structure and switching process.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. Mechanisms by Which Interleukin-12 Corrects Defective NK Cell Anticryptococcal Activity in HIV-Infected Patients

    Directory of Open Access Journals (Sweden)

    Stephen K. Kyei

    2016-08-01

    Full Text Available Cryptococcus neoformans is a pathogenic yeast and a leading cause of life-threatening meningitis in AIDS patients. Natural killer (NK cells are important immune effector cells that directly recognize and kill C. neoformans via a perforin-dependent cytotoxic mechanism. We previously showed that NK cells from HIV-infected patients have aberrant anticryptococcal killing and that interleukin-12 (IL-12 restores the activity at least partially through restoration of NKp30. However, the mechanisms causing this defect or how IL-12 restores the function was unknown. By examining the sequential steps in NK cell killing of Cryptococcus, we found that NK cells from HIV-infected patients had defective binding of NK cells to C. neoformans. Moreover, those NK cells that bound to C. neoformans failed to polarize perforin-containing granules to the microbial synapse compared to healthy controls, suggesting that binding was insufficient to restore a defect in perforin polarization. We also identified lower expression of intracellular perforin and defective perforin release from NK cells of HIV-infected patients in response to C. neoformans. Importantly, treatment of NK cells from HIV-infected patients with IL-12 reversed the multiple defects in binding, granule polarization, perforin content, and perforin release and restored anticryptococcal activity. Thus, there are multiple defects in the cytolytic machinery of NK cells from HIV-infected patients, which cumulatively result in defective NK cell anticryptococcal activity, and each of these defects can be reversed with IL-12.

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

    Science.gov (United States)

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

    2018-06-01

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

  14. Clinical significance of 201Tl reverse redistribution in patients with aorto-coronary bypass surgery

    International Nuclear Information System (INIS)

    Nishimura, Tsunehiko; Uehara, Tashiisa; Hayashida, Kohei; Kozuka, Takahira

    1987-01-01

    Detection of myocardial ischemia by the stress thallium scan has traditionally been performed using transient defect analysis on exercise, followed by redistribution studies. Worsening of the 201 Tl myocardial image from exercise to redistribution is referred to as reverse redistribution. In this study, we found reverse redistribution in 10 (21%) of 48 angina pectoris patients who had undergone aortocoronary bypass surgery. The clinical significance of this phenomenon in these patients was investigated in relation to angiographic and surgical findings. Reverse redistribution was found to occur in regions which were supplied by bypass grafts. These areas showed increased coronary blood flow and rapid thallium washout. Our results indicate that a perfusion defect in the bypass region of the redistribution image might be caused by relatively rapid washout in the bypass graft region compared to the adjacent normal myocardium. These results should be considered in the clinical interpretation of stress thallium scans. (orig.)

  15. Reverse Anterolateral Thigh Flap to Revise a Below-knee Amputation Stump at the Mid-tibial Level

    Directory of Open Access Journals (Sweden)

    Parviz Lionel Sadigh, MB ChB

    2013-12-01

    Full Text Available Summary: The reconstruction of defects around the knee often poses a challenge due to the limited availability of local soft tissues. Indeed, this same problem is encountered when attempting to revise a below-knee amputation stump. Moreover, due to a paucity of recipient vessels in those who have undergone previous amputation secondary to trauma, free-flap reconstruction is often challenging and not always successful. We report a case of a reverse anterolateral thigh (ALT flap used to revise a long below-knee amputation stump. Previous reports in the literature attest to the versatility of the reverse ALT to cover defects around the knee and proximal tibia, but to our knowledge, this is the first report of a reverse ALT reaching to the mid-tibial level.

  16. Structural analysis of retinal photoreceptor ellipsoid zone and postreceptor retinal layer associated with visual acuity in patients with retinitis pigmentosa by ganglion cell analysis combined with OCT imaging

    Science.gov (United States)

    Liu, Guodong; Li, Hui; Liu, Xiaoqiang; Xu, Ding; Wang, Fang

    2016-01-01

    Abstract The aim of this study was to examine changes in photoreceptor ellipsoid zone (EZ) and postreceptor retinal layer in retinitis pigmentosa (RP) patients by ganglion cell analysis (GCA) combined with optical coherence tomography (OCT) imaging to evaluate the structure–function relationships between retinal layer changes and best corrected visual acuity (BCVA). Sixty-eight eyes of 35 patients with RP and 65 eyes of 35 normal controls were analyzed in the study. The average length of EZ was 911.1 ± 208.8 μm in RP patients, which was shortened with the progression of the disease on the OCT images. The average ganglion cell–inner plexiform layer thickness (GCIPLT) was 54.7 ± 18.9 μm in RP patients, while in normal controls it was 85.6 ± 6.8 μm. The GCIPLT in all quarters became significantly thinner along with outer retinal thinning. There was a significantly positive correlation between BCVA and EZ (r = −0.7622, P retinal layer changes from a new perspective in RP patients, which suggests that EZ and GCIPLT obtained by GCA combined with OCT imaging are the direct and valid indicators to diagnosis and predict the pathological process of RP. PMID:28033301

  17. Hydrogen interaction with radiation defects in p-type silicon

    CERN Document Server

    Feklisova, O V; Yakimov, E B; Weber, J

    2001-01-01

    Hydrogen interaction with radiation defects in p-type silicon has been investigated by deep-level non-stationary spectroscopy. Hydrogen is introduced into the high-energy electron-irradiated crystals under chemical etching in acid solutions at room temperature followed by the reverse-bias annealing at 380 K. It is observed that passivation of the irradiation-induced defects is accompanied by formation of novel electrically active defects with hydrogen-related profiles. Effect of hydrogen on the electrical activity of the C sub s C sub i complexes is shown for the first time. Based on the spatial distribution and passivation kinetics, possible nature of the novel complexes is analyzed. The radii for hydrogen capture by vacancies, K-centers, C sub s C sub i centers and the novel complexes are determined

  18. Fatigue failure of sandwich beams with face sheet wrinkle defects

    DEFF Research Database (Denmark)

    Leong, Martin Klitgaard; Hvejsel, C.F.; Thomsen, Ole Thybo

    2012-01-01

    This paper presents experimental fatigue results for GFRP face sheet/balsa core sandwich beams with face sheet wrinkle defects, subjected to fully reversed in-plane fatigue loading. An estimate of the fatigue design limit is presented, based on static test results, finite element analyses and app...

  19. Targeted reversion of induced pluripotent stem cells from patients with human cleidocranial dysplasia improves bone regeneration in a rat calvarial bone defect model.

    Science.gov (United States)

    Saito, Akiko; Ooki, Akio; Nakamura, Takashi; Onodera, Shoko; Hayashi, Kamichika; Hasegawa, Daigo; Okudaira, Takahito; Watanabe, Katsuhito; Kato, Hiroshi; Onda, Takeshi; Watanabe, Akira; Kosaki, Kenjiro; Nishimura, Ken; Ohtaka, Manami; Nakanishi, Mahito; Sakamoto, Teruo; Yamaguchi, Akira; Sueishi, Kenji; Azuma, Toshifumi

    2018-01-22

    Runt-related transcription factor 2 (RUNX2) haploinsufficiency causes cleidocranial dysplasia (CCD) which is characterized by supernumerary teeth, short stature, clavicular dysplasia, and osteoporosis. At present, as a therapeutic strategy for osteoporosis, mesenchymal stem cell (MSC) transplantation therapy is performed in addition to drug therapy. However, MSC-based therapy for osteoporosis in CCD patients is difficult due to a reduction in the ability of MSCs to differentiate into osteoblasts resulting from impaired RUNX2 function. Here, we investigated whether induced pluripotent stem cells (iPSCs) properly differentiate into osteoblasts after repairing the RUNX2 mutation in iPSCs derived from CCD patients to establish normal iPSCs, and whether engraftment of osteoblasts derived from properly reverted iPSCs results in better regeneration in immunodeficient rat calvarial bone defect models. Two cases of CCD patient-derived induced pluripotent stem cells (CCD-iPSCs) were generated using retroviral vectors (OCT3/4, SOX2, KLF4, and c-MYC) or a Sendai virus SeVdp vector (KOSM302L). Reverted iPSCs were established using programmable nucleases, clustered regularly interspaced short palindromic repeats (CRISPR)/Cas-derived RNA-guided endonucleases, to correct mutations in CCD-iPSCs. The mRNA expressions of osteoblast-specific markers were analyzed using quantitative reverse-transcriptase polymerase chain reaction. iPSCs-derived osteoblasts were transplanted into rat calvarial bone defects, and bone regeneration was evaluated using microcomputed tomography analysis and histological analysis. Mutation analysis showed that both contained nonsense mutations: one at the very beginning of exon 1 and the other at the initial position of the nuclear matrix-targeting signal. The osteoblasts derived from CCD-iPSCs (CCD-OBs) expressed low levels of several osteoblast differentiation markers, and transplantation of these osteoblasts into calvarial bone defects created in rats with

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

    International Nuclear Information System (INIS)

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

    2008-01-01

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

  1. Radiation defects in electron-irradiated InP crystals

    International Nuclear Information System (INIS)

    Brailovskii, E.Yu.; Karapetyan, F.K.; Megela, I.G.; Tartachnik, V.P.

    1982-01-01

    The results are presented of formation and annealing of defects in InP crystals at 1 to 50 MeV electron irradiation. The recovery of electrical properties in the range of 77 to 970 K during annealing processes is studied. Five low temperature annealing states in n-InP and the reverse annealing in p-InP are observed at 77 to 300 K. Four annealing stages at temperatures higher than 300 K are present. When the electron energy is increased more complicated thermostable defects are formed, and at 50 MeV electron energy besides of the point defect clusters are formed, which anneal at temperatures of 800 to 970 K. It is shown that the peculiarities of the Hall mobility at irradiation and annealing are caused by the scattering centres E/sub c/ - 0.2 eV. The 'limiting' position of the Fermi level in electron irradiated InP crystals is discussed. (author)

  2. Radiation defects in electron-irradiated InP crystals

    Energy Technology Data Exchange (ETDEWEB)

    Brailovskii, E.Yu.; Karapetyan, F.K.; Megela, I.G.; Tartachnik, V.P. (AN Ukrainskoj SSR, Kiev. Inst. Yadernykh Issledovanij)

    1982-06-16

    The results are presented of formation and annealing of defects in InP crystals at 1 to 50 MeV electron irradiation. The recovery of electrical properties in the range of 77 to 970 K during annealing processes is studied. Five low temperature annealing states in n-InP and the reverse annealing in p-InP are observed at 77 to 300 K. Four annealing stages at temperatures higher than 300 K are present. When the electron energy is increased more complicated thermostable defects are formed, and at 50 MeV electron energy besides of the point defect clusters are formed, which anneal at temperatures of 800 to 970 K. It is shown that the peculiarities of the Hall mobility at irradiation and annealing are caused by the scattering centres E/sub c/ - 0.2 eV. The 'limiting' position of the Fermi level in electron irradiated InP crystals is discussed.

  3. Synthesis of ZnTe nanowires onto TiO2 nanotubular arrays by pulse-reverse electrodeposition

    International Nuclear Information System (INIS)

    Gandhi, T.; Raja, K.S.; Misra, M.

    2009-01-01

    Growth of ZnTe nanowires using a pulse-reverse electrodeposition technique from a non-aqueous solution is reported. ZnTe nanowires were grown on to an ordered nanotubular TiO 2 template in a propylene carbonate solution at 130 o C inside a controlled atmosphere glove box. The pulse-reverse electro deposition process consisted of a cathodic pulse at - 0.62 V and an anodic pulse at 0.75 V Vs Zn 2+ /Zn. Stoichiometry growth of crystalline ZnTe nanowires was observed in the as-deposited condition. The anodic pulse cycle of the pulse-reverse electrodeposition process presumably introduced zinc vacancies as deep level acceptors at an energy level of E v + 0.47 eV. The resultant ZnTe nanowires showed p-type semiconductivity with a resistivity of 7.8 x 10 4 Ω cm and a charge carrier density of 1.67 x 10 14 cm -3 . Annihilation of the defects occurred upon thermal annealing that resulted in marginal decrease in the defect density.

  4. Influence of columnar defects on the thermodynamic properties of BSCCO

    Science.gov (United States)

    van der Beek, C. J.; Indenbom, M. V.; Berseth, V.; Konczykowski, M.; Li, T. W.; Kes, P. H.; Benoit, W.

    1996-03-01

    Amorphous columnar defects strongly affect the reversible magnetization of Bi2Sr2CaCu2O8+δ single crystals both in the vortex solid, where the change reflects the change in vortex energy due to pinning, and in the vortex liquid, where the randomly positioned columns disrupt the interaction between superconducting fluctuations.

  5. Reversible cold-induced abnormalities in myocardial perfusion and function in systemic sclerosis

    International Nuclear Information System (INIS)

    Alexander, E.L.; Firestein, G.S.; Weiss, J.L.; Heuser, R.R.; Leitl, G.; Wagner, H.N. Jr.; Brinker, J.A.; Ciuffo, A.A.; Becker, L.C.

    1986-01-01

    The effects of peripheral cold exposure on myocardial perfusion and function were studied in 13 patients with scleroderma without clinically evident myocardial disease. Ten patients had at least one transient, cold-induced, myocardial perfusion defect visualized by thallium-201 scintigraphy, and 12 had reversible, cold-induced, segmental left ventricular hypokinesis by two-dimensional echocardiography. The 10 patients with transient perfusion defects all had anatomically corresponding ventricular wall motion abnormalities. No one in either of two control groups (9 normal volunteers and 7 patients with chest pain and normal coronary arteriograms) had cold-induced abnormalities. This study is the first to show the simultaneous occurrence of cold-induced abnormalities in myocardial perfusion and function in patients with scleroderma. The results suggest that cold exposure in such patients may elicit transient reflex coronary vasoconstriction resulting in reversible myocardial ischemia and dysfunction. Chronic recurrent episodes of coronary spasm may lead to focal myocardial fibrosis

  6. Overexpressed of RAD51 suppresses recombination defects: a possible mechanism to reverse genomic instability

    Energy Technology Data Exchange (ETDEWEB)

    Schild, David; Wiese, Claudia

    2009-10-15

    RAD51, a key protein in the homologous recombinational DNA repair (HRR) pathway, is the major strand-transferase required for mitotic recombination. An important early step in HRR is the formation of single-stranded DNA (ss-DNA) coated by RPA (a ss-DNA binding protein). Displacement of RPA by RAD51 is highly regulated and facilitated by a number of different proteins known as the 'recombination mediators'. To assist these recombination mediators, a second group of proteins also is required and we are defining these proteins here as 'recombination co-mediators'. Defects in either recombination mediators or comediators, including BRCA1 and BRCA2, lead to impaired HRR that can genetically be complemented for (i.e. suppressed) by overexpression of RAD51. Defects in HRR have long been known to contribute to genomic instability leading to tumor development. Since genomic instability also slows cell growth, precancerous cells presumably require genomic restabilization to gain a growth advantage. RAD51 is overexpressed in many tumors, and therefore, we hypothesize that the complementing ability of elevated levels of RAD51 in tumors with initial HRR defects limits genomic instability during carcinogenic progression. Of particular interest, this model may also help explain the high frequency of TP53 mutations in human cancers, since wild-type p53 represses RAD51.

  7. A comparison of the M3/M4 metastable defect detected in hydrogen and ICP Ar plasma treated n-GaAs

    International Nuclear Information System (INIS)

    Nyamhere, C.; Venter, A.

    2012-01-01

    Defects created by a dc hydrogen plasma have been compared to those observed in n-GaAs exposed to an inductively coupled (ICP) Ar plasma. The reference sample (in the case of H-plasma treated material) contained two prominent native deep level electron traps, possibly M4 and E C −0.56 eV, which were both passivated by hydrogen. Plasma treatment also resulted in the formation of a defect observed at 0.58 eV (M3) below the conduction band. This defect transforms back into what is believed to be M4 when annealed at 350 K for 3 h under reverse bias. These two defects compare well with two similar defects observed in the Ar ICP treated samples also showing metastable behavior. Additionally, the electrical characterization of Schottky barrier diodes on n-GaAs, prior to and after hydrogen passivation shows that, depending on the plasma conditions, the plasma ions significantly damage the surface resulting in poor rectifying contacts. The damage is considerably reversed/repaired upon annealing between the room temperature and 573 K (300 °C).

  8. A comparison of the M3/M4 metastable defect detected in hydrogen and ICP Ar plasma treated n-GaAs

    Energy Technology Data Exchange (ETDEWEB)

    Nyamhere, C., E-mail: cloud.nyamhere@nmmu.ac.za [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa); Venter, A. [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa)

    2012-05-15

    Defects created by a dc hydrogen plasma have been compared to those observed in n-GaAs exposed to an inductively coupled (ICP) Ar plasma. The reference sample (in the case of H-plasma treated material) contained two prominent native deep level electron traps, possibly M4 and E{sub C}-0.56 eV, which were both passivated by hydrogen. Plasma treatment also resulted in the formation of a defect observed at 0.58 eV (M3) below the conduction band. This defect transforms back into what is believed to be M4 when annealed at 350 K for 3 h under reverse bias. These two defects compare well with two similar defects observed in the Ar ICP treated samples also showing metastable behavior. Additionally, the electrical characterization of Schottky barrier diodes on n-GaAs, prior to and after hydrogen passivation shows that, depending on the plasma conditions, the plasma ions significantly damage the surface resulting in poor rectifying contacts. The damage is considerably reversed/repaired upon annealing between the room temperature and 573 K (300 Degree-Sign C).

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

    Science.gov (United States)

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

    2017-11-01

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

  10. Time course of transient cortical scintigraphic defects associated with acute pyelonephritis

    Energy Technology Data Exchange (ETDEWEB)

    Ditchfield, Michael R.; Summerville, Dianne; Cook, David J.; Campo, John F. de [Department of Radiology, Royal Children' s Hospital, Melbourne 3052 (Australia); Grimwood, Keith; Nolan, Terrance M. [Department of General Paediatrics, Royal Children' s Hospital, Melbourne (Australia); Department of Paediatrics, University of Melbourne, Melbourne (Australia); Powell, Harley R. [Department of Nephrology, Royal Children' s Hospital, Melbourne (Australia); Sloane, Robert [Department of General Paediatrics, Royal Children' s Hospital, Melbourne (Australia)

    2002-12-01

    Acute pyelonephritis is distinguished from renal scarring using repeat cortical scintigraphy. The defects of acute pyelonephritis resolve, while those of scars persist. To determine the duration of reversible cortical defects following acute pyelonephritis and the time interval required to differentiate infection from scars. Materials and methods. An observational prospective study of 193 children (386 kidneys) aged less than 5 years following their first proven urinary tract infection (UTI). Renal cortical scintigraphic defects were detected in 112 (29%) kidneys within 15 days of diagnosis. Of these, 95 underwent repeat renal cortical scans 2 years after the UTI, including 50 with additional scans performed within 2-6 months of infection. Of the 50 kidneys undergoing a second renal cortical scan within 2-6 months of the first UTI, 22 (44%) had persistent defects. A third scan was performed on 17 (77%) kidneys after 2 years, by which time defects had resolved in another 8 (47%) kidneys. The predictive value of defects detected within 2-6 months of UTI representing scars is 53% (95% CI 28, 77). Overall, nine (18%) kidneys with initial renal cortical abnormalities had permanent defects. In the 45 kidneys undergoing a second cortical scan more than 6 months after the UTI, 11 (24%) had persistent defects. None of the 95 kidneys undergoing serial scans developed new or larger defects. Renal scars may not be reliably diagnosed by cortical scintigraphy performed within 6 months of UTI because the inflammatory lesions may not have fully resolved. (orig.)

  11. Time course of transient cortical scintigraphic defects associated with acute pyelonephritis

    International Nuclear Information System (INIS)

    Ditchfield, Michael R.; Summerville, Dianne; Cook, David J.; Campo, John F. de; Grimwood, Keith; Nolan, Terrance M.; Powell, Harley R.; Sloane, Robert

    2002-01-01

    Acute pyelonephritis is distinguished from renal scarring using repeat cortical scintigraphy. The defects of acute pyelonephritis resolve, while those of scars persist. To determine the duration of reversible cortical defects following acute pyelonephritis and the time interval required to differentiate infection from scars. Materials and methods. An observational prospective study of 193 children (386 kidneys) aged less than 5 years following their first proven urinary tract infection (UTI). Renal cortical scintigraphic defects were detected in 112 (29%) kidneys within 15 days of diagnosis. Of these, 95 underwent repeat renal cortical scans 2 years after the UTI, including 50 with additional scans performed within 2-6 months of infection. Of the 50 kidneys undergoing a second renal cortical scan within 2-6 months of the first UTI, 22 (44%) had persistent defects. A third scan was performed on 17 (77%) kidneys after 2 years, by which time defects had resolved in another 8 (47%) kidneys. The predictive value of defects detected within 2-6 months of UTI representing scars is 53% (95% CI 28, 77). Overall, nine (18%) kidneys with initial renal cortical abnormalities had permanent defects. In the 45 kidneys undergoing a second cortical scan more than 6 months after the UTI, 11 (24%) had persistent defects. None of the 95 kidneys undergoing serial scans developed new or larger defects. Renal scars may not be reliably diagnosed by cortical scintigraphy performed within 6 months of UTI because the inflammatory lesions may not have fully resolved. (orig.)

  12. Pulse reverse plating for integrated magnetics on Si

    International Nuclear Information System (INIS)

    Roy, S.; Connell, A.; Ludwig, M.; Wang, N.; O'Donnell, T.; Brunet, M.; McCloskey, P.; OMathuna, C.; Barman, A.; Hicken, R.J.

    2005-01-01

    Thin film microtransformers have been fabricated on silicon with Ni 45 Fe 55 as a core material. Fractal/dendritic growths are observed in the patterned cores in DC electroplating due to the enhancement of localized current density at defect/nucleation sites. A 'pulser' device was made in house to produce forward and reverse current of the required amplitude for a particular duration. The combination of a low amplitude long (millisecond) forward pulse and a short (microsecond) high-amplitude reverse pulse gave dendrite-free plated cores with a uniform thickness and alloy composition over a 3D topology of a microrough substrate surface. Finally, we characterized the material in situ by small signal electrical measurements, and with MOKE hysteresis loops measured on a complete device

  13. Fatigue Failure of Sandwich Beams with Wrinkle Defects Used for Wind Turbine Blades

    DEFF Research Database (Denmark)

    Leong, Martin Klitgaard; Hvejsel, C.F.; Lund, Erik

    2012-01-01

    Glass fiber face sheet/balsa wood core sandwich beams with out-of-plane fiber misalignments/wrinkle defects were subjected to in-plane fully reversed fatigue loading and the failure modes were documented. A fatigue life design limit was estimated using finite element analyses and the Northwestern...

  14. Tailored lithium storage performance of graphene aerogel anodes with controlled surface defects for lithium-ion batteries

    International Nuclear Information System (INIS)

    Shan, Hui; Xiong, Dongbin; Li, Xifei; Sun, Yipeng; Yan, Bo; Li, Dejun; Lawes, Stephen; Cui, Yanhua; Sun, Xueliang

    2016-01-01

    Graphical abstract: - Highlights: • The graphene aerogel (GA) with controllable surface defects was synthesized. • The graphene aerogel anodes showed high specific capacity and excellent cyclability. • Surface defects on the GA significantly function for lithium storage. • This study can extend the application of the graphene anodes for LIBs. - Abstract: Three dimensional self-assembled graphene aerogel (GA) anode materials with some surface defects have been successfully generated through a facile hydrothermal procedure using graphene oxide as precursor. The morphologies and textural properties of as-obtained GA were investigated by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman and other spectroscopy techniques. The surface defects and electrical conductivities of GA can be controlled by adjusting the hydrothermal reaction time. The results indicate that GA with a reaction time of 6 h exhibits extremely high reversible capacity (1430 mAh g"−"1 at the current density of 100 mA g"−"1) and superior rate capability (587 mAh g"−"1 at 800 mA g"−"1) with excellent cycling stability (maintaining a reversible capacity of 960 mAh g"−"1 at 100 mA g"−"1 after 100 cycles). It is demonstrated that the 3D porous network with increased defect density, as well as the considerable electrical conductivity, results in the excellent electrochemical performance of the as-made GA anodes in lithium-ion batteries.

  15. 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.

    Science.gov (United States)

    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.

  16. Defects and defect processes in nonmetallic solids

    CERN Document Server

    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.

  17. A theoretical investigation of defects in a boron nitride monolayer

    International Nuclear Information System (INIS)

    Azevedo, Sergio; Kaschny, J R; Castilho, Caio M C de; Mota, F de Brito

    2007-01-01

    We have investigated, using first-principles calculations, the energetic stability and structural properties of antisites, vacancies and substitutional carbon defects in a boron nitride monolayer. We have found that the incorporation of a carbon atom substituting for one boron atom, in an N-rich growth condition, or a nitrogen atom, in a B-rich medium, lowers the formation energy, as compared to antisites and vacancy defects. We also verify that defects, inducing an excess of nitrogen or boron, such as N B and B N , are more stable in its reverse atmosphere, i.e. N B is more stable in a B-rich growth medium, while B N is more stable in a N-rich condition. In addition we have found that the formation energy of a C N , in a N-rich medium, and C B in a B-rich medium, present formation energies comparable to those of the vacancies, V N and V B , respectively

  18. Detection of small surface defects using DCT based enhancement approach in machine vision systems

    Science.gov (United States)

    He, Fuqiang; Wang, Wen; Chen, Zichen

    2005-12-01

    Utilizing DCT based enhancement approach, an improved small defect detection algorithm for real-time leather surface inspection was developed. A two-stage decomposition procedure was proposed to extract an odd-odd frequency matrix after a digital image has been transformed to DCT domain. Then, the reverse cumulative sum algorithm was proposed to detect the transition points of the gentle curves plotted from the odd-odd frequency matrix. The best radius of the cutting sector was computed in terms of the transition points and the high-pass filtering operation was implemented. The filtered image was then inversed and transformed back to the spatial domain. Finally, the restored image was segmented by an entropy method and some defect features are calculated. Experimental results show the proposed small defect detection method can reach the small defect detection rate by 94%.

  19. EXTENDED REVERSE SURAL FLAP FOR LOWER LIMB COVERAGE

    Directory of Open Access Journals (Sweden)

    Biswajit Mishra

    2018-12-01

    Full Text Available BACKGROUND The reverse sural artery flap has been a workhorse for the reconstruction of distal third of leg, ankle, sole and foot. Major limitation of reverse sural flap has been venous congestion particularly when harvested from proximal third of the leg. Objective- To evaluate the efficacy, safety of the extended reverse sural flap from proximal third of the leg. MATERIALS AND METHODS A prospective study was conducted at the department of plastic surgery on twenty patients who needed soft tissue reconstruction in the distal third of the leg, ankle, heel, forefoot and midfoot due to various cause. In all cases flap was extended proximally to the upper third of the calf and neurovenoadipo fascial pedicled sural fasciocutaneous flap was harvested. RESULTS There were only two cases of marginal necrosis. None of the patients had complete necrosis. Two patients developed hypertrophy of the flap margin. CONCLUSION Distally based neuroveno adipofascial pedicled sural fasciocutaneous flap can be safely extended to proximal third of the leg and is a reliable option for reconstruction of the defects in the foot, ankle and sole.

  20. Prevalence of symptomatic and silent stress-induced perfusion defects in diabetic patients with suspected coronary artery disease referred for myocardial perfusion scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Prior, John O.; Calcagni, Maria-Lucia; Bischof Delaloye, Angelika [Centre Hospitalier Universitaire Vaudois (CHUV University Hospital), Division of Nuclear Medicine, Lausanne (Switzerland); Monbaron, David; Ruiz, Juan [Centre Hospitalier Universitaire Vaudois (CHUV University Hospital), Division of Endocrinology, Diabetology and Metabolism, Lausanne (Switzerland); Koehli, Melanie [Centre Hospitalier Universitaire Vaudois (CHUV University Hospital), Division of Nuclear Medicine, Lausanne (Switzerland); Centre Hospitalier Universitaire Vaudois (CHUV University Hospital), Division of Endocrinology, Diabetology and Metabolism, Lausanne (Switzerland)

    2005-01-01

    Silent myocardial ischaemia - as evaluated by stress-induced perfusion defects on myocardial perfusion scintigraphy (MPS) in patients without a history of chest pain - is frequent in diabetes and is associated with increased rates of cardiovascular events. Its prevalence has been determined in asymptomatic diabetic patients, but remains largely unknown in diabetic patients with suspected coronary artery disease (CAD) in the clinical setting. In this study we therefore sought (a) to determine the prevalence of symptomatic and silent perfusion defects in diabetic patients with suspected CAD and (b) to characterise the eventual predictors of abnormal perfusion. The patient population comprised 133 consecutive diabetic patients with suspected CAD who had been referred for MPS. Studies were performed with exercise (41%) or pharmacological stress testing (1-day protocol, {sup 99m}Tc-sestamibi, {sup 201}Tl or both). We used semi-quantitative analysis (20-segment polar maps) to derive the summed stress score (SSS) and the summed difference score (SDS). Abnormal MPS (SSS{>=}4) was observed in 49 (37%) patients (SSS=4.9{+-}8.4, SDS=2.4{+-}4.7), reversible perfusion defects (SDS{>=}2) in 40 (30%) patients [SSS=13.3{+-}10.9; SDS=8.0{+-}5.6; 20% moderate to severe (SDS>4), 7% multivessel] and fixed defects in 21 (16%) patients. Results were comparable between patients with and patients without a history of chest pain. Of 75 patients without a history of chest pain, 23 (31%, 95% CI=21-42%) presented reversible defects (SSS=13.9{+-}11.3; SDS=7.4{+-}1.2), indicative of silent ischaemia. Reversible defects were associated with inducible ST segment depression during MPS stress (odds ratio (OR)=3.2, p<0.01). Fixed defects were associated with erectile dysfunction in males (OR=3.7, p=0.02) and lower aspirin use (OR=0.25, p=0.02). Silent stress-induced perfusion defects occurred in 31% of the patients, a rate similar to that in patients with a history of chest pain. MPS could identify

  1. Atomic structure of pyramidal defects in GaN:Mg: Influence of annealing

    Energy Technology Data Exchange (ETDEWEB)

    Liliental-Weber, Z.; Tomaszewicz, T.; Zakharov, D.; O' Keefe, M. [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Hautakangas, S.; Saarinen, K. [Materials Science and Engineering, University of California, Berkeley, Berkeley, CA 94720 (United States); Freitas, J.A.; Henry, R.L. [ESTD-Electronic Materials Branch, Naval Research Laboratory, Washington, D.C. 20375 (United States)

    2006-05-15

    The atomic structure of the characteristic defects (Mg-rich hexagonal pyramids) in p-doped bulk and MOCVD GaN:Mg thin films grown with Ga polarity was determined at atomic resolution by direct reconstruction of the scattered electron wave in a transmission electron microscope. Small cavities were present inside the defects, confirmed also with positron annihilation. The inside walls of the cavities were covered by GaN of reverse polarity compared to the matrix. Annealing of the MOCVD layers lead to slight increase of the defect size and an increase of the room temperature photoluminescence intensity. Positron annihilation confirms presence of vacancy clusters of different sizes triggered by the Mg doping in as-grown samples and decrease of their concentration upon annealing at 900 and 1000 C. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Oxygen optical gas sensing by reversible fluorescence quenching in photo-oxidized poly(9,9-dioctylfluorene) thin films.

    Science.gov (United States)

    Anni, M; Rella, R

    2010-02-04

    We investigated the fluorescence (FL) dependence on the environment oxygen content of poly(9,9-dioctylfluorene) (PF8) thin films. We show that the PF8 interactions with oxygen are not limited to the known irreversible photo-oxidation, resulting in the formation of Keto defects, but also reversible FL quenching is observed. This effect, which is stronger for the Keto defects than for the PF8, has been exploited for the realization of a prototype oxygen sensor based on FL quenching. The sensing sensitivity of Keto defects is comparable with the state of the art organic oxygen sensors based on phosphorescence quenching.

  3. Reversible myocardial ischaemia or irreversible myocardial fibrosis

    International Nuclear Information System (INIS)

    Mathey, D.; Hanrath, P.; Kupper, W.; Bleifeld, W.; Montz, R.; Knop, J.; Stritzke, P.; Kroeger, E.; Bleese, N.

    1978-01-01

    The results of biphasis 201 thallium ( 201 Tl) scanning were compared with those of coronary arteriography, left ventricular angiography and stress ECG in 56 patients with coronary artery disease and six with no evidence of heart disease. There were 104 201 Tl defects, 50 of them reversible. The defects were always located in the area supplied by a critically stenotic coronary artery. Correlation of regional wall motion with 201 Tl activity demonstrated that in all forms of abnormal wall motion there was either ischaemia or fibrosis. The resting LV angiogram thus does not make it possible to distinguish between myocardial ischaemia and fibrosis. Taking the LV angiogram as a standard, the rate of false-positive 201 Tl scintigrams was 5%, that of false-negative ones 23%. The biphasic 201 Tl scintigram was more sensitive than the stress ECG in detecting myocardial ischaemia. It furthermore made it possible to localize the ischaemic (or fibrotic) region within the LV and to estimate its size. (orig.) [de

  4. Supracristal ventricular septal defect with severe right coronary cusp prolapse

    International Nuclear Information System (INIS)

    Hussain, A.H.; Hanif, B.; Khan, G.; Hasan, K.

    2011-01-01

    The case of a 20 years old male, diagnosed as supracristal ventricular septal defect (VSD) for last 6 years is being presented. He came in emergency department with decompensated congestive cardiac failure. After initial stabilization, he underwent trans thoracic echocardiogram which showed large supracristal VSD, severely prolapsing right coronary cusp, severe aortic regurgitation and severe pulmonary hypertension. Right heart catheterization was performed which documented reversible pulmonary vascular resistance after high flow oxygen inhalation. He underwent VSD repair, right coronary cusp was excised and aortic valve was replaced by mechanical prosthesis. Post operative recovery was uneventful. He was discharged home in one week.The case of a 20 years old male, diagnosed as supracristal ventricular septal defect (VSD) for last 6 years is being presented. He came in emergency department with decompensated congestive cardiac failure. After initial stabilization, he underwent trans thoracic echocardiogram which showed large supracristal VSD, severely prolapsing right coronary cusp, severe aortic regurgitation and severe pulmonary hypertension. Right heart catheterization was performed which documented reversible pulmonary vascular resistance after high flow oxygen inhalation. He underwent VSD repair, right coronary cusp was excised and aortic valve was replaced by mechanical prosthesis. Post operative recovery was uneventful. He was discharged home in one week. (author)

  5. Ultrasonic Stimulation of Mouse Skin Reverses the Healing Delays in Diabetes and Aging by Activation of Rac1.

    Science.gov (United States)

    Roper, James A; Williamson, Rosalind C; Bally, Blandine; Cowell, Christopher A M; Brooks, Rebecca; Stephens, Phil; Harrison, Andrew J; Bass, Mark D

    2015-11-01

    Chronic skin-healing defects are one of the leading challenges to lifelong well-being, affecting 2-5% of populations. Chronic wound formation is linked to age and diabetes and frequently leads to major limb amputation. Here we identify a strategy to reverse fibroblast senescence and improve healing rates. In healthy skin, fibronectin activates Rac1 in fibroblasts, causing migration into the wound bed, and driving wound contraction. We discover that mechanical stimulation of the skin with ultrasound can overturn healing defects by activating a calcium/CamKinaseII/Tiam1/Rac1 pathway that substitutes for fibronectin-dependent signaling and promotes fibroblast migration. Treatment of diabetic and aged mice recruits fibroblasts to the wound bed and reduces healing times by 30%, restoring healing rates to those observed in young, healthy animals. Ultrasound treatment is equally effective in rescuing the healing defects of animals lacking fibronectin receptors, and can be blocked by pharmacological inhibition of the CamKinaseII pathway. Finally, we discover that the migration defects of fibroblasts from human venous leg ulcer patients can be reversed by ultrasound, demonstrating that the approach is applicable to human chronic samples. By demonstrating that this alternative Rac1 pathway can substitute for that normally operating in the skin, we identify future opportunities for management of chronic wounds.

  6. Defects of the Glycinergic Synapse in Zebrafish

    Science.gov (United States)

    Ogino, Kazutoyo; Hirata, Hiromi

    2016-01-01

    Glycine mediates fast inhibitory synaptic transmission. Physiological importance of the glycinergic synapse is well established in the brainstem and the spinal cord. In humans, the loss of glycinergic function in the spinal cord and brainstem leads to hyperekplexia, which is characterized by an excess startle reflex to sudden acoustic or tactile stimulation. In addition, glycinergic synapses in this region are also involved in the regulation of respiration and locomotion, and in the nociceptive processing. The importance of the glycinergic synapse is conserved across vertebrate species. A teleost fish, the zebrafish, offers several advantages as a vertebrate model for research of glycinergic synapse. Mutagenesis screens in zebrafish have isolated two motor defective mutants that have pathogenic mutations in glycinergic synaptic transmission: bandoneon (beo) and shocked (sho). Beo mutants have a loss-of-function mutation of glycine receptor (GlyR) β-subunit b, alternatively, sho mutant is a glycinergic transporter 1 (GlyT1) defective mutant. These mutants are useful animal models for understanding of glycinergic synaptic transmission and for identification of novel therapeutic agents for human diseases arising from defect in glycinergic transmission, such as hyperekplexia or glycine encephalopathy. Recent advances in techniques for genome editing and for imaging and manipulating of a molecule or a physiological process make zebrafish more attractive model. In this review, we describe the glycinergic defective zebrafish mutants and the technical advances in both forward and reverse genetic approaches as well as in vivo visualization and manipulation approaches for the study of the glycinergic synapse in zebrafish. PMID:27445686

  7. Ultra-selective defect-free interfacially polymerized molecular sieve thin-film composite membranes for H2 purification

    KAUST Repository

    Ali, Zain; Pacheco Oreamuno, Federico; Litwiller, Eric; Wang, Yingge; Han, Yu; Pinnau, Ingo

    2017-01-01

    method for reverse osmosis membranes. Defect-free thin-film composite membranes were formed demonstrating unprecedented mixed-gas H2/CO2 selectivity of ≈ 50 at 140 °C with H2 permeance of 350 GPU, surpassing the permeance/selectivity upper bound of all

  8. Optically reversible electrical soft-breakdown in wide-bandgap oxides—A factorial study

    Science.gov (United States)

    Zhou, Y.; Ang, D. S.; Kalaga, P. S.

    2018-04-01

    In an earlier work, we found that an electrical soft-breakdown region in wide-bandgap oxides, such as hafnium dioxide, silicon dioxide, etc., could be reversed when illuminated by white light. The effect is evidenced by a decrease in the breakdown leakage current, termed as a negative photoconductivity response. This finding raises the prospect for optical sensing applications based on these traditionally non-photo-responsive but ubiquitous oxide materials. In this study, we examine the statistical distribution for the rate of breakdown reversal as well as the influence of factors such as wavelength, light intensity, oxide stoichiometry (or oxygen content) and temperature on the reversal rate. The rate of breakdown reversal is shown to be best described by the lognormal distribution. Light in the range of ˜400-700 nm is found to have relatively little influence on the reversal rate. On the other hand, light intensity, oxygen content and temperature, each of them has a clear impact; a stronger light intensity, an oxide that is richer in oxygen content and a reduced temperature all speed up the reversal process substantially. These experimental results are consistent with the proposed phenomenological redox model involving photo-assisted recombination of the surrounding oxygen interstitials with vacancy defects in the breakdown path.

  9. Prevalence of symptomatic and silent stress-induced perfusion defects in diabetic patients with suspected coronary artery disease referred for myocardial perfusion scintigraphy

    International Nuclear Information System (INIS)

    Prior, John O.; Calcagni, Maria-Lucia; Bischof Delaloye, Angelika; Monbaron, David; Ruiz, Juan; Koehli, Melanie

    2005-01-01

    Silent myocardial ischaemia - as evaluated by stress-induced perfusion defects on myocardial perfusion scintigraphy (MPS) in patients without a history of chest pain - is frequent in diabetes and is associated with increased rates of cardiovascular events. Its prevalence has been determined in asymptomatic diabetic patients, but remains largely unknown in diabetic patients with suspected coronary artery disease (CAD) in the clinical setting. In this study we therefore sought (a) to determine the prevalence of symptomatic and silent perfusion defects in diabetic patients with suspected CAD and (b) to characterise the eventual predictors of abnormal perfusion. The patient population comprised 133 consecutive diabetic patients with suspected CAD who had been referred for MPS. Studies were performed with exercise (41%) or pharmacological stress testing (1-day protocol, 99m Tc-sestamibi, 201 Tl or both). We used semi-quantitative analysis (20-segment polar maps) to derive the summed stress score (SSS) and the summed difference score (SDS). Abnormal MPS (SSS≥4) was observed in 49 (37%) patients (SSS=4.9±8.4, SDS=2.4±4.7), reversible perfusion defects (SDS≥2) in 40 (30%) patients [SSS=13.3±10.9; SDS=8.0±5.6; 20% moderate to severe (SDS>4), 7% multivessel] and fixed defects in 21 (16%) patients. Results were comparable between patients with and patients without a history of chest pain. Of 75 patients without a history of chest pain, 23 (31%, 95% CI=21-42%) presented reversible defects (SSS=13.9±11.3; SDS=7.4±1.2), indicative of silent ischaemia. Reversible defects were associated with inducible ST segment depression during MPS stress (odds ratio (OR)=3.2, p<0.01). Fixed defects were associated with erectile dysfunction in males (OR=3.7, p=0.02) and lower aspirin use (OR=0.25, p=0.02). Silent stress-induced perfusion defects occurred in 31% of the patients, a rate similar to that in patients with a history of chest pain. MPS could identify these patients with a

  10. Anterior Cranial Base Reconstruction with a Reverse Temporalis Muscle Flap and Calvarial Bone Graft

    Directory of Open Access Journals (Sweden)

    Seung Gee Kwon

    2012-07-01

    Full Text Available BackgroundCranial base defects are challenging to reconstruct without serious complications. Although free tissue transfer has been used widely and efficiently, it still has the limitation of requiring a long operation time along with the burden of microanastomosis and donor site morbidity. We propose using a reverse temporalis muscle flap and calvarial bone graft as an alternative option to a free flap for anterior cranial base reconstruction.MethodsBetween April 2009 and February 2012, cranial base reconstructions using an autologous calvarial split bone graft combined with a reverse temporalis muscle flap were performed in five patients. Medical records were retrospectively analyzed and postoperative computed tomography scans, magnetic resonance imaging, and angiography findings were examined to evaluate graft survival and flap viability.ResultsThe mean follow-up period was 11.8 months and the mean operation time for reconstruction was 8.4±3.36 hours. The defects involved the anterior cranial base, including the orbital roof and the frontal and ethmoidal sinus. All reconstructions were successful. Viable flap vascularity and bone survival were observed. There were no serious complications except for acceptable donor site depressions, which were easily corrected with minor procedures.ConclusionsThe reverse temporalis muscle flap could provide sufficient bulkiness to fill dead space and sufficient vascularity to endure infection. The calvarial bone graft provides a rigid framework, which is critical for maintaining the cranial base structure. Combined anterior cranial base reconstruction with a reverse temporalis muscle flap and calvarial bone graft could be a viable alternative to free tissue transfer.

  11. Reversal of diaschisis by zolpidem

    International Nuclear Information System (INIS)

    Claus, R.P.; Nel, H.W.; Sathekge, M.

    2004-01-01

    Full text: Introduction: Recent literature has reported on clinical improvement after zolpidem, a GABAergic anti insomnia drug, in brain injury and stroke patients. In this study, the effect of zolpidem on crossed cerebellar diaschisis was investigated in such patients. Method: Four patients with crossed cerebellar diaschisis after brain injury or stroke were investigated before and after application of 10 mg zolpidem by 99mTc HMPAO brain SPECT. Result: Apart from clinical improvements, 99mTc HMPAO brain SPECT studies showed reversal of the crossed cerebellar diaschisis and improvement of perfusion defects after zolpidem. Conclusion: 99mTc HMPAO brain SPECT may have a role to pre-select brain injury and stroke patients who will benefit clinically from zolpidem therapy. (author)

  12. Is there any advantage to the acquisition of 24-hour thallium images, in the presence of persistent perfusion defects at 4 h after reinjection?

    International Nuclear Information System (INIS)

    Bobba, K.; Botvinick, E.H.; Sciammarella, M.G.; Starsken, N.F.; Zhu, Y.Y.; Lapidus, A.; Dae, M.W.

    1998-01-01

    We determined the incidence of delayed 24-h reversibility post thallium-201 reinjection and imaging at 4 h, as well as the prognostic and significance of such delayed reversibility. We studied 46 consecutive patients with persistent thallium-201 perfusion or incompletely reversible SPET perfusion defects acquired within 10 min after reinjection performed 4 h after stress. In 38 of 46 patients 24-h images showed no further reversibility beyond the post-reinjection 4-h study (group A). Eight of 46 patients demonstrated reversibility on 24-h imaging (group B). Of these eight, three patients showed no improvement compared with the post-stress images, with a mean perfusion score of the abnormal segments of 1.25±0.50 on the 4-h images, and of 3.00 on the 24-h images. Four patients presented with nine mixed regions. Four of these regions showed an improvement in the mean perfusion score of 2.50±0.58 on 4- and 24-h images. Two of them, with moderate/severe defects, demonstrated complete reversibility at 4-h post-reinjection imaging. In addition, five other regions presented no improvement at 4-h imaging, but showed an improvement in the mean perfusion score from 0.80±0.84 at 4-h to 3.30±0.89 at 24-h imaging. Two of these regions in one patient showed a severe perfusion score of 0 at 4 h, and complete reversibility at 24 hours. Another patient had three severe perfusion defects; two of them redistributed partially at 4 h and completely at 24 h. The remaining segment with a perfusion score of 0 at 4 h, presented complete reversibility at 24 h. Two patients revealed significant reversibility at 24 h in a region that was severely underperfused after post-reinjection imaging at 4 h. Among group B patients, 75% had recent acute ischemic syndrome, compared with only 13% in group A. Among 11 patients with unstable angina, six had evidence of delayed 24-h reversibility, compared with 2 of 35 patients without clinically acute ischemia. On follow-up, there were seven cardiac

  13. Is there any advantage to the acquisition of 24-hour thallium images, in the presence of persistent perfusion defects at 4 h after reinjection?

    Energy Technology Data Exchange (ETDEWEB)

    Bobba, K.; Botvinick, E.H.; Sciammarella, M.G.; Starsken, N.F.; Zhu, Y.Y.; Lapidus, A.; Dae, M.W. [Nuclear Medicine Section, Department of Radiology, Cardiovascular Division, Department of Medicine, and the Cardiovascular Research Institute, University of California, San Francisco (United States)

    1998-05-01

    We determined the incidence of delayed 24-h reversibility post thallium-201 reinjection and imaging at 4 h, as well as the prognostic and significance of such delayed reversibility. We studied 46 consecutive patients with persistent thallium-201 perfusion or incompletely reversible SPET perfusion defects acquired within 10 min after reinjection performed 4 h after stress. In 38 of 46 patients 24-h images showed no further reversibility beyond the post-reinjection 4-h study (group A). Eight of 46 patients demonstrated reversibility on 24-h imaging (group B). Of these eight, three patients showed no improvement compared with the post-stress images, with a mean perfusion score of the abnormal segments of 1.25{+-}0.50 on the 4-h images, and of 3.00 on the 24-h images. Four patients presented with nine mixed regions. Four of these regions showed an improvement in the mean perfusion score of 2.50{+-}0.58 on 4- and 24-h images. Two of them, with moderate/severe defects, demonstrated complete reversibility at 4-h post-reinjection imaging. In addition, five other regions presented no improvement at 4-h imaging, but showed an improvement in the mean perfusion score from 0.80{+-}0.84 at 4-h to 3.30{+-}0.89 at 24-h imaging. Two of these regions in one patient showed a severe perfusion score of 0 at 4 h, and complete reversibility at 24 hours. Another patient had three severe perfusion defects; two of them redistributed partially at 4 h and completely at 24 h. The remaining segment with a perfusion score of 0 at 4 h, presented complete reversibility at 24 h. Two patients revealed significant reversibility at 24 h in a region that was severely underperfused after post-reinjection imaging at 4 h. Among group B patients, 75% had recent acute ischemic syndrome, compared with only 13% in group A. Among 11 patients with unstable angina, six had evidence of delayed 24-h reversibility, compared with 2 of 35 patients without clinically acute ischemia. On follow-up, there were seven

  14. Simulation of Ultrasonic Beam Focusing on a Defect in Anisotropic, Inhomogeneous Media

    International Nuclear Information System (INIS)

    Jeong, Hyun Jo; Cho, Sung Jong; Erdenetuya, Sharaa; Jung, Duck Yong

    2011-01-01

    In ultrasonic testing of dissimilar metal welds, application of phased array technique in terms of incident beam focusing is not easy because of complicated material structures formed during the multi-pass welding process. Time reversal(TR) techniques can overcome some limitations of phased array since they are self-focusing that does not depend on the geometrical and physical properties of testing components. In this paper, we test the possibility of TR focusing on a defect within anisotropic, heterogeneous austenitic welds. A commercial simulation software is employed for TR focusing and imaging of a side-drilled hole. The performance of time reversed adaptive focal law is compared with those of calculated focal laws for both anisotropic and isotropic welds

  15. Acousto-defect interaction in irradiated and non-irradiated silicon n+-p structures

    Science.gov (United States)

    Olikh, O. Ya.; Gorb, A. M.; Chupryna, R. G.; Pristay-Fenenkov, O. V.

    2018-04-01

    The influence of ultrasound on current-voltage characteristics of non-irradiated silicon n+-p structures as well as silicon structures exposed to reactor neutrons or 60Co gamma radiation has been investigated experimentally. It has been found that the ultrasound loading of the n+-p structure leads to the reversible change of shunt resistance, carrier lifetime, and ideality factor. Specifically, considerable acoustically induced alteration of the ideality factor and the space charge region lifetime was observed in the irradiated samples. The experimental results were described by using the models of coupled defect level recombination, Shockley-Read-Hall recombination, and dislocation-induced impedance. The experimentally observed phenomena are associated with the increase in the distance between coupled defects as well as the extension of the carrier capture coefficient of complex point defects and dislocations. It has been shown that divacancies and vacancy-interstitial oxygen pairs are effectively modified by ultrasound in contrast to interstitial carbon-interstitial oxygen complexes.

  16. Hydrogen trapping by VC precipitates and structural defects in a high strength Fe–Mn–C steel studied by small-angle neutron scattering

    International Nuclear Information System (INIS)

    Malard, B.; Remy, B.; Scott, C.; Deschamps, A.; Chêne, J.; Dieudonné, T.; Mathon, M.H.

    2012-01-01

    Highlights: ► SANS was used to study the interaction between H and a Fe–Mn–C steel containing V. ► No interaction between H and V in solid solution has been detected. ► A reversible interaction between H and structural defects has been measured. ► 5 ppm wt. of H can be trapped in the VC nanoprecipitates. - Abstract: The trapping of hydrogen by VC precipitates and structural defects in high strength Fe–Mn–C steel was studied by small angle neutron scattering. No interaction between H and V in solid solution has been detected but a significant interaction between H and structural defects introduced by plastic deformation has been measured. This last effect was reversible upon outgassing of the H. Moreover a significant interaction between H and VC precipitates has been measured; 5 ppm wt. of H could be trapped in the precipitates. This is consistent with the homogeneous trapping of H within the precipitates rather than at the precipitate/matrix interface.

  17. 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

    DEFF Research Database (Denmark)

    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...

  18. Reproducibility of quantitative planar thallium-201 scintigraphy: quantitative criteria for reversibility of myocardial perfusion defects

    International Nuclear Information System (INIS)

    Sigal, S.L.; Soufer, R.; Fetterman, R.C.; Mattera, J.A.; Wackers, F.J.

    1991-01-01

    Fifty-two paired stress/delayed planar 201 TI studies (27 exercise studies, 25 dipyridamole studies) were processed twice by seven technologists to assess inter- and intraobserver variability. The reproducibility was inversely related to the size of 201 Tl perfusion abnormalities. Intraobserver variability was not different between exercise and dipyridamole studies for lesions of similar size. Based upon intraobserver variability, objective quantitative criteria for reversibility of perfusion abnormalities were defined. These objective criteria were tested prospectively in a separate group of 35 201 Tl studies and compared with the subjective interpretation of quantitative circumferential profiles. Overall, exact agreement existed in 78% of images (kappa statistic k = 0.66). We conclude that quantification of planar 201 Tl scans is highly reproducible, with acceptable inter- and intraobserver variability. Objective criteria for lesion reversibility correlated well with analysis by experienced observers

  19. Reverse leakage current characteristics of InGaN/GaN multiple quantum well ultraviolet/blue/green light-emitting diodes

    Science.gov (United States)

    Zhou, Shengjun; Lv, Jiajiang; Wu, Yini; Zhang, Yuan; Zheng, Chenju; Liu, Sheng

    2018-05-01

    We investigated the reverse leakage current characteristics of InGaN/GaN multiple quantum well (MQW) near-ultraviolet (NUV)/blue/green light-emitting diodes (LEDs). Experimental results showed that the NUV LED has the smallest reverse leakage current whereas the green LED has the largest. The reason is that the number of defects increases with increasing nominal indium content in InGaN/GaN MQWs. The mechanism of the reverse leakage current was analyzed by temperature-dependent current–voltage measurement and capacitance–voltage measurement. The reverse leakage currents of NUV/blue/green LEDs show similar conduction mechanisms: at low temperatures, the reverse leakage current of these LEDs is attributed to variable-range hopping (VRH) conduction; at high temperatures, the reverse leakage current of these LEDs is attributed to nearest-neighbor hopping (NNH) conduction, which is enhanced by the Poole–Frenkel effect.

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

    Science.gov (United States)

    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.

  1. Birth Defects

    Science.gov (United States)

    A birth defect is a problem that happens while a baby is developing in the mother's body. Most birth defects happen during the first 3 months of ... in the United States is born with a birth defect. A birth defect may affect how the ...

  2. Nanometer-size magnetic domains and coherent magnetization reversal in a giant exchange-bias system

    DEFF Research Database (Denmark)

    Dufour, C.; Fitzsimmons, M. R.; Borchers, J. A.

    2011-01-01

    The role of magnetic domains and domain walls in exchange bias has stimulated much contemporary deliberation. Here we present compelling evidence obtained with small-angle scattering of unpolarized- and polarized-neutron beams that magnetization reversal occurs via formation of 10-100s nm-sized m...... to that of structural defects at the seed-layer-superlattice interface....

  3. [Research and application of computer-aided technology in restoration of maxillary defect].

    Science.gov (United States)

    Cheng, Xiaosheng; Liao, Wenhe; Hu, Qingang; Wang, Qian; Dai, Ning

    2008-08-01

    This paper presents a new method of designing restoration model of maxillectomy defect through Computer aided technology. Firstly, 3D maxillectomy triangle mesh model is constructed from Helical CT data. Secondly, the triangle mesh model is transformed into initial computer-aided design (CAD) model of maxillectomy through reverse engineering software. Thirdly, the 3D virtual restoration model of maxillary defect is obtained after designing and adjusting the initial CAD model through CAD software according to the patient's practical condition. Therefore, the 3D virtual restoration can be fitted very well with the broken part of maxilla. The exported design data can be manufactured using rapid prototyping technology and foundry technology. Finally, the result proved that this method is effective and feasible.

  4. Retinal, visual, and refractive development in retinopathy of prematurity

    Science.gov (United States)

    Moskowitz, Anne; Hansen, Ronald M; Fulton, Anne B

    2016-01-01

    The pivotal role of the neurosensory retina in retinopathy of prematurity (ROP) disease processes has been amply demonstrated in rat models. We have hypothesized that analogous cellular processes are operative in human ROP and have evaluated these presumptions in a series on non-invasive investigations of the photoreceptor and post-receptor peripheral and central retina in infants and children. Key results are slowed kinetics of phototransduction and deficits in photoreceptor sensitivity that persist years after ROP has completely resolved based on clinical criteria. On the other hand, deficits in post-receptor sensitivity are present in infancy regardless of the severity of the ROP but are not present in older children if the ROP was so mild that it never required treatment and resolved without a clinical trace. Accompanying the persistent deficits in photoreceptor sensitivity, there is increased receptive field size and thickening of the post-receptor retinal laminae in the peripheral retina of ROP subjects. In the late maturing central retina, which mediates visual acuity, attenuation of multifocal electroretinogram activity in the post-receptor retina led us to the discovery of a shallow foveal pit and significant thickening of the post-receptor retinal laminae in the macular region; this is most likely due to failure of the normal centrifugal movement of the post-receptor cells during foveal development. As for refractive development, myopia, at times high, is more common in ROP subjects than in control subjects, in accord with refractive findings in other populations of former preterms. This information about the neurosensory retina enhances understanding of vision in patients with a history of ROP, and taken as a whole, raises the possibility that the neurosensory retina is a target for therapeutic intervention. PMID:28539805

  5. Grain boundary cavitation under reversed constant stress

    International Nuclear Information System (INIS)

    Hales, R.

    1978-06-01

    The growth of grain boundary cavities by diffusion processes has been examined for cyclic stresses. It is found that the time required to grow a void by a predetermined amount (tsub(t)) is always longer than the time required to shrink the same defect to its original size (tsub(c)) under reversed stress. The ratio tsub(c)/tsub(t) is a function of the magnitude of the applied stress and tensile hold time. Similar calculations have been performed for gas filled bubbles. Similar results to those for voids are found at long hold times, but a significantly different ratio of tsub(c)/tsub(t) is obtained at short times. (author)

  6. The reverse boomerang sign: a marker for first-trimester transposition of great arteries.

    Science.gov (United States)

    Bravo-Valenzuela, Nathalie Jeanne; Peixoto, Alberto Borges; Araujo Júnior, Edward; Da Silva Costa, Fabricio; Meagher, Simon

    2017-10-12

    To describe a new sonographic marker of transposition of great arteries (TGA) during the first-trimester screening. We reviewed six cases of TGA from 2013 to 2016 in which an antenatal diagnosis of TGA at first-trimester screening (11-13 + 6 weeks of gestation) was confirmed postnatally. We specifically assessed images obtained by scanning the fetal heart in three vessels (3V) and three-vessel with trachea (3VT) views using color Doppler. The "reverse boomerang" sign was defined as a reverse curvature of right ventricle outflow tract (RVOT) at level of the 3VT view. We described six cases of confirmed TGA, five singletons and one twin pregnancy, among which only two vessels and the reverse curvature of RVOT (reverse boomerang sign) was demonstrated in the first-trimester screening at level of 3VT view. Ventricular septal defects were observed in three cases, and double outlet right ventricle in one case. No other cardiac or extracardiac anomalies were identified. Termination of pregnancy was not performed in any case. Our series case suggests that the reverse boomerang sign may improve the early prenatal screening for TGA.

  7. Influence of oxygen on the annealing of radioactive defects in germanium

    International Nuclear Information System (INIS)

    Gasimov, G.M.; Mustafayev, Yn.M.; Gasimova, V.G.

    2002-01-01

    The isochronal annealing were carried out in the wide temperature range, for the establishment of oxygen influence on the annealing of radioactive defects (Rd) in any radiated germanium samples, concentrated with oxygen up to concentration of 9.7·10 16 cm -3 . It is shown that the curves of isochronal annealing of one of the such samples 1, with primary current charge concentration of 9.0·10 cm 14 , radiated by integral electron flow of φ= 8.0·10 16 cm -3 , at 293 K and also the non-oxygen samples 2, with primary concentration of 1.7·10 cm -3 , radiated at above mentioned conditions. The sample 1 is converted by radiation to p-type, but the conversion not occur in samples 2. It is illustrated, that that there is two annealing stage at 340-430 K, for the samples 2, which in results takes place the complete annealing of the RD. At 300 K the annealing takes place in samples of 1, but at 340 K - the reverse annealing of RD. The sample was at compensated state in the temperature range of 360-400 K. An annealing of RD takes place again at 440 K and the sample re-converted its conductivity type. The reverse annealing at 480 K, and at about 510 K, the substantial annealing of the defects has been observed, which in results a sample restores it's primary parameters. The carried out experiments show that as in converted, and also in n-type be samples, Is observed the reverse annealing of RD, but the reverse annealing of current charge carriers in n-type samples is observed only at such conditions, of the integral flow of accelerated elections exceeds the primary concentration of current charge carriers about 4 time of magnitude (φ≥4n 0 ). Besides, the complete annealing of RD in germanium samples concentrated with oxygen, takes place at more high temperatures in comparison with the non-oxygen samples

  8. Osteogenic capability of autologous rabbit adipose-derived stromal cells in repairing calvarial defects.

    Science.gov (United States)

    Cheng, Shao-Wen; Lin, Zhong-Qin; Wang, Wei; Zhang, Wei; Kou, Dong-Quan; Ying, Xiao-Zhou; Chen, Qing-Yu; Shen, Yue; Cheng, Xiao-Jie; Peng, Lei; Lv, Chuan-Zhu

    2011-01-01

    To evaluate the in vitro and in vivo osteogenic capability of adipose-derived stromal cells (ASCs). ASCs were isolated from New Zealand white rabbits and determined by alkaline phosphatase (ALP) staining, von Kossa staining and alizarin red staining. Some specific markers of osteogenic differentiation, including ALP, osteocalcin (OCN), osteopontin (OPN) were examined by reverse transcription-polymerase chain reaction (RT-PCR). In vivo, demineralized bone matrix (DBM)-ASCs composites were implanted into the rabbit calvarial defects created at each side of the longitudinal midline. After 6 weeks, histologic properties of the transplants were analyzed. ASCs were successfully induced into osteogenesis. ALP staining, von Kossa staining and alizarin red staining showed positive results. The expressions of ALP, OCN and OPN were detected in ASCs after cultivation in osteogenic medium. Extensive new bone was observed in the defects transplanted with DBM-ASCs composites. ASCs have the potential to differentiate into osteogenic lineage and DBM-ASCs constructs are a promising method for regeneration in bone defects.

  9. A half-century of studies of growth hormone insensitivity/Laron syndrome: A historical perspective.

    Science.gov (United States)

    Rosenbloom, Arlan L

    2016-06-01

    A growth hormone (GH) dependent substance responsible for sulfate uptake by costal cartilage of hypophysectomized rats, labeled sulfation factor, was reported in 1957. In 1962 the radioimmunoassay for GH was described. The clinical picture of severe GH deficiency but with high serum concentrations of GH was reported in 3 siblings in 1966 and followed by a 1968 report of 22 patients belonging to 14 consanguineous oriental Jewish families in Israel. Defective sulfation factor generation was demonstrated in 15 of these individuals and in a 1971 report; FFA response to IV GH and growth response to GH injections suggested competitive saturation of peripheral tissue receptors by an abnormal GH. However, studies published in 1973 demonstrated normal fractionation of their circulating GH, and normal binding of GH from 22 patients to various antisera used for radioimmunoassay. In 1976, the Israeli investigators reported that circulating GH from 7 patients reacted normally in the recently developed radioreceptor assay for GH. In 1984, using hepatic microsome pellets, they demonstrated that the defect was a failure of GH binding to receptors. Characterization of the human GH receptor (GHR) gene, reported in 1989, included the initial description of a genetic defect of the GHR in 2 of 9 Israeli patients. At about the same time began the identification in Ecuador of what was to become the largest population of GH insensitivity in the world, ~100 individuals, and the only substantial population with a common mutation of the GH receptor. Treatment studies with recombinant IGF-I began in 1990. Growth response was modest compared to that of GH treated GH deficient subjects. The spectrum of GH insensitivity has expanded beyond GH receptor deficiency to include postreceptor abnormalities: IGF-I gene mutation (1996); IGF-I receptor mutation (2003); signal transducer and activator of transcription 5b mutation (2003); and mutation of the GH-dependent acid labile subunit (2004). Rare

  10. Luminance and chromatic signals interact differently with melanopsin activation to control the pupil light response.

    Science.gov (United States)

    Barrionuevo, Pablo A; Cao, Dingcai

    2016-09-01

    Intrinsically photosensitive retinal ganglion cells (ipRGCs) express the photopigment melanopsin. These cells receive afferent inputs from rods and cones, which provide inputs to the postreceptoral visual pathways. It is unknown, however, how melanopsin activation is integrated with postreceptoral signals to control the pupillary light reflex. This study reports human flicker pupillary responses measured using stimuli generated with a five-primary photostimulator that selectively modulated melanopsin, rod, S-, M-, and L-cone excitations in isolation, or in combination to produce postreceptoral signals. We first analyzed the light adaptation behavior of melanopsin activation and rod and cones signals. Second, we determined how melanopsin is integrated with postreceptoral signals by testing with cone luminance, chromatic blue-yellow, and chromatic red-green stimuli that were processed by magnocellular (MC), koniocellular (KC), and parvocellular (PC) pathways, respectively. A combined rod and melanopsin response was also measured. The relative phase of the postreceptoral signals was varied with respect to the melanopsin phase. The results showed that light adaptation behavior for all conditions was weaker than typical Weber adaptation. Melanopsin activation combined linearly with luminance, S-cone, and rod inputs, suggesting the locus of integration with MC and KC signals was retinal. The melanopsin contribution to phasic pupil responses was lower than luminance contributions, but much higher than S-cone contributions. Chromatic red-green modulation interacted with melanopsin activation nonlinearly as described by a "winner-takes-all" process, suggesting the integration with PC signals might be mediated by a postretinal site.

  11. Comprehensive Study of Solar Cell Structure Defects by Means of Noise and Light Emission Analysis

    Directory of Open Access Journals (Sweden)

    Robert Macku

    2012-01-01

    Full Text Available This paper discusses the issue of silicon solar cells localized defects from metrological and physical points of view. Structure imperfections represent the real problem because of solar cells long-term degradation and conversion efficiency decreasing. To this aim we pay our attention to research relating to the defect light emission and correlation with rectangular microplasma fluctuation. A sensitive CCD camera has been used for mapping of surface photon emission. The operation point of the samples has been set to reverse bias mode, and different electric field intensity was applied. We managed to get interesting information using a combination of optical investigation and electrical noise measurement in time and spectral domain. It will be revealed that a direct correlation between noise and photon emission exists and the results related to several defect spots are presented in detail in this paper.

  12. Clinical value and severity of myocardial perfusion defects in asymptomatic diabetic patients with negative or weakly positive exercise treadmill test

    International Nuclear Information System (INIS)

    Zakavi, Seyed Rasoul; Taherpour, Mehdi; Moossavi, Zohreh; Sadeghi, Ramin; Kakhki, Vahidreza Dabbagh; Rokni, Haleh

    2013-01-01

    Although coronary artery disease (CAD) is the leading cause of death in type 2 diabetic patients, it is frequently asymptomatic. Myocardial perfusion imaging (MPI) is reported to show ischemia in a significant number of asymptomatic diabetic patients. We studied the prevalence and severity of myocardial perfusion defects in asymptomatic diabetic patients and its clinical impact. One hundred thirty consecutive asymptomatic patients, aged 35-65 years with type 2 diabetes mellitus and with no history of CAD and no cardiac symptoms were recruited in the study. Echocardiography, electrocardiography (ECG), routine laboratory tests and exercise treadmill test (ETT) were performed and patients with weakly positive or negative ETT underwent Dipyridamole MPI. Patients with positive ETT were referred to coronary angiography. Patients were followed for at least 17 months (mean 21.7 months) and any cardiac event was recorded. We studied 81 female and 49 male patients with mean age of 51.8 years. Negative, weakly positive and positive ETT result was noted in 74.3%, 15% and 10.7% respectively. 75% of patients with positive ETT had coronary artery disease in angiography. Gated myocardial perfusion SPECT was done in 106 patients. MPI showed reversible defect in 26.9% of the patients with a mean summed stress score of 3.3±1.8. Follow up completed in 112 patients and only one patient with abnormal MPI underwent coronary angiography followed by PTCA. No cardiac death, MI, UA or hospital admission occurred among our patients during follow up (17-26 months). Mean stress end diastolic volume (EDV) was significantly higher in patients with reversible defect compared to patients without reversible defect based on MPI findings (62.0±31.6 Vs 48.5±18.4 ml, P=0.04). Blood glucose and HbA1c were significantly higher in patients with ischemia compared to patients without ischemia (P<0.05). Meanwhile the ratio of TG to HDL was 6.06±3.2 in ischemic patients compared to 4.8±2.3 in normal

  13. I2 basal stacking fault as a degradation mechanism in reverse gate-biased AlGaN/GaN HEMTs

    Science.gov (United States)

    Lang, A. C.; Hart, J. L.; Wen, J. G.; Miller, D. J.; Meyer, D. J.; Taheri, M. L.

    2016-09-01

    Here, we present the observation of a bias-induced, degradation-enhancing defect process in plasma-assisted molecular beam epitaxy grown reverse gate-biased AlGaN/GaN high electron mobility transistors (HEMTs), which is compatible with the current theoretical framework of HEMT degradation. Specifically, we utilize both conventional transmission electron microscopy and aberration-corrected transmission electron microscopy to analyze microstructural changes in not only high strained regions in degraded AlGaN/GaN HEMTs but also the extended gate-drain access region. We find a complex defect structure containing an I2 basal stacking fault and offer a potential mechanism for device degradation based on this defect structure. This work supports the reality of multiple failure mechanisms during device operation and identifies a defect potentially involved with device degradation.

  14. Solution-diffusion with defects model for pressure-assisted forward osmosis

    KAUST Repository

    Duan, Jintang

    2014-11-01

    An osmosis transport model is presented that combines the standard internal and external concentration polarization equations in the forward osmosis (FO) field with the selective layer transport equations first proposed by Sherwood in 1967. The Sherwood model describes water flux as the sum of a solute-selective, diffusive component driven by the sum of osmotic pressure and hydraulic pressure differences, and a nonselective, convective component driven by hydraulic pressure difference only. This solution-diffusion with defects (SDWD) model and the solution-diffusion (SD) model were compared against data collected using polyamide thin-film-composite (PA-TFC) and integrally-skinned asymmetric cellulose triacetate (CTA) membranes, evaluated in various configurations. When tested with pure water on the porous support side and 1.5. M (π=72.7. bar) sodium chloride solution on the selective layer side, applying 1.25. bar of hydraulic pressure to the porous support side increased water flux by an order of magnitude for PA-TFC membranes, but had negligible effect on CTA membrane flux. These large flux variations can be explained by the SDWD model, but not the SD model. To confirm the existence of defects, a PA-TFC membrane was coated with a uniform, highly water-permeable, nonselective polymer. After coating to block convection through defects, the influence of hydraulic pressure on water flux through this membrane essentially disappeared. Water flux through these defects is low (<1% of total water flux for PA-TFC membranes) and of little consequence in practical FO or reverse osmosis (RO) applications. But in pressure-assisted forward osmosis (PAFO) or pressure-retarded osmosis (PRO), convective transport through defects affects the solute concentration difference across the membrane selective layer, increasing or decreasing water flux through defect-free regions. The presence of defects may explain why membrane power density in PRO is lower than that predicted based on

  15. First interactions between hydrogen and stress-induced reverse transformation of Ni-Ti superelastic alloy

    Science.gov (United States)

    Yokoyama, Ken'ichi; Hashimoto, Tatsuki; Sakai, Jun'ichi

    2017-11-01

    The first dynamic interactions between hydrogen and the stress-induced reverse transformation have been investigated by performing an unloading test on a Ni-Ti superelastic alloy subjected to hydrogen charging under a constant applied strain in the elastic deformation region of the martensite phase. Upon unloading the specimen, charged with a small amount of hydrogen, no change in the behaviour of the stress-induced reverse transformation is observed in the stress-strain curve, although the behaviour of the stress-induced martensite transformation changes. With increasing amount of hydrogen charging, the critical stress for the reverse transformation markedly decreases. Eventually, for a larger amount of hydrogen charging, the reverse transformation does not occur, i.e. there is no recovery of the superelastic strain. The residual martensite phase on the side surface of the unloaded specimen is confirmed by X-ray diffraction. Upon training before the unloading test, the properties of the reverse transformation slightly recover after ageing in air at room temperature. The present study indicates that to change the behaviour of the reverse transformation a larger amount of hydrogen than that for the martensite transformation is necessary. In addition, it is likely that a substantial amount of hydrogen in solid solution more strongly suppresses the reverse transformation than hydrogen trapped at defects, thereby stabilising the martensite phase.

  16. Improved Healing of Large, Osseous, Segmental Defects by Reverse Dynamization: Evaluation in a Sheep Model

    Science.gov (United States)

    2017-12-01

    project: mechanical testing Name: Miguel Trujillo, PhD Project role: Research Scientist Nearest person month worked: 2 Contribution to project...formation and maturation. This article describes a novel strat- egy in which the defect is first stabi- lized at low axial stiffness, with subsequent...in a commercial company or institution related directly or indirectly to the subject of this article . J Am Acad Orthop Surg 2016;24: e60-e61 http

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

    Science.gov (United States)

    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.

  18. Reversible flowchart languages and the structured reversible program theorem

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2008-01-01

    Many irreversible computation models have reversible counterparts, but these are poorly understood at present. We introduce reversible flowcharts with an assertion operator and show that any reversible flowchart can be simulated by a structured reversible flowchart using only three control flow...... operators. Reversible flowcharts are r- Turing-complete, meaning that they can simuluate reversible Turing machines without garbage data. We also demonstrate the injectivization of classical flowcharts into reversible flowcharts. The reversible flowchart computation model provides a theoretical...

  19. Functional antigen binding by the defective B cells of CBA/N mice.

    Science.gov (United States)

    Snippe, H; Merchant, B; Lizzio, E F; Inman, J K

    1982-01-01

    CBA/N mice have an X-linked B cell defect which prevents them from responding to nonmitogenic thymic independent (TI-2) antigens such as dinitrophenylated DNP-Ficoll (1,2). The F1 male progeny of CBA/N female mice express the same defect. Spleen cell suspensions from such defective mice (CBA/N X C3H/HeN F1 males) could not respond to DNP-Ficoll following in vitro immunization and subsequent transfer into irradiated, syngeneic, F1 male recipients as expected. In contrast, normal CBA/N X C3H/HeN F1 female spleen cells could respond and effect a "rescue"; they mounted strong plaque-forming cell responses 7 days after in vitro exposure to DNP-Ficoll and subsequent transfer into irradiated F1 male recipients. Defective F1 male spleen cells, however, could bind significant quantities of 125I-DNP-Ficoll after in vitro exposure. Extensive washing of these spleen cells could not reverse this binding. Such DNP-Ficoll-exposed and washed F1 male spleen cells could, after transfer, aid normal untreated F1 female cells in their rescue function. The defective F1 male spleen cells could convey immunogenic quantities of DNP-Ficoll to the "rescuing" F1 female cells. Mitomycin treatment of F1 male cells did not interfere with their conveyor function. Goat anti-mouse mu serum impeded the passive antigen conveyor function of defective F1 male cells as did prior exposure to high concentrations of free DNP hapten. Our data support the view that the B cell defect of CBA/N X C3H/HeN F1 male mice does not relate to antigen binding, but rather to an inability to be effectively triggered by certain cell-bound polymeric antigens.

  20. Management of Anterior Abdominal Wall Defect Using a Pedicled Tensor Fascia Lata Flap: A Case Report

    Directory of Open Access Journals (Sweden)

    K. D. Ojuka

    2012-01-01

    Full Text Available Degloving injuries to anterior abdominal wall are rare due to the mechanism of injury. Pedicled tensor fascia lata is known to be a versatile flap with ability to reach the lower anterior abdomen. A 34-year-old man who was involved in a road traffic accident presented with degloving injury and defect at the left inguinal region, sigmoid colon injury, and scrotal bruises. At investigation, he was found to have pelvic fracture. The management consisted of colostomy and tensor fascia lata to cover the defect at reversal. Though he developed burst abdomen on fifth postoperative day, the flap healed with no complications.

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

    DEFF Research Database (Denmark)

    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...

  2. Reverse Algols

    Science.gov (United States)

    Leung, K. C.

    1989-01-01

    Reverse Algols, binary systems with a semidetached configuration in which the more massive component is in contact with the critical equipotential surface, are examined. Observational evidence for reverse Algols is presented and the parameters of seven reverse Algols are listed. The evolution of Algols and reverse Algols is discussed. It is suggested that, because reverse Algols represent the premass-reversal semidetached phase of close binary evolution, the evolutionary time scale between regular and reverse Algols is the ratio of the number of confirmed systems of these two Algol types.

  3. Association between left ventricular perfusion defects and myocardial deformation indexes in heart transplantation recipients.

    Science.gov (United States)

    D'Andrea, Antonello; De Rimini, Maria Luisa; America, Raffaella; Cirillo, Chiara; Riegler, Lucia; Limongelli, Giuseppe; D'Alto, Michele; Salerno, Gemma; Maiello, Ciro; Muto, Pietro; Russo, Maria Giovanna; Calabrò, Raffaele; Bossone, Eduardo; Pacileo, Giuseppe

    2017-10-01

    The aim of the study was to analyze possible correlations between strain echocardiography (STE) and PET myocardial perfusion in a population of heart transplantation (HTx) recipients showing preserved left ventricular (LV) ejection fraction. By STE, LV global longitudinal strain (LV GLS) was lower in HTx. PET showed no transient or chronic ischemia in 83 of 115 HTx (73%). Fixed perfusion defects were observed in 17% of HTx and reversible ischemia in 10%. Significant coronary stenosis was observed only in 10 cases. GLS was independently associated with age at HTx and fixed perfusion defects (HR 0.41; P<.001). Such relationships underline STE ability to early identify HTx pts with subclinical myocardial dysfunction during long-term follow-up. © 2017, Wiley Periodicals, Inc.

  4. Defect modelling

    International Nuclear Information System (INIS)

    Norgett, M.J.

    1980-01-01

    Calculations, drawing principally on developments at AERE Harwell, of the relaxation about lattice defects are reviewed with emphasis on the techniques required for such calculations. The principles of defect modelling are outlined and various programs developed for defect simulations are discussed. Particular calculations for metals, ionic crystals and oxides, are considered. (UK)

  5. Osteogenic capability of autologous rabbit adipose-derived stromal cells in repairing calvarial defects

    Directory of Open Access Journals (Sweden)

    CHENG Shao-wen

    2012-02-01

    Full Text Available 【Abstract】Objective: To evaluate the in vitro and in vivo osteogenic capability of adipose-derived stromal cells (ASCs. Methods: ASCs were isolated from New Zealand white rabbits and determined by alkaline phosphatase (ALP staining, von Kossa staining and alizarin red staining. Some specific markers of osteogenic differentiation, including ALP, osteocalcin (OCN, osteopontin (OPN were examined by reverse transcription-polymerase chain reaction (RT-PCR. In vivo, demineralized bone matrix (DBM-ASCs composites were implanted into the rabbit calvarial defects created at each side of the longitudinal midline. After 6 weeks, histologic properties of the transplants were analyzed. Results: ASCs were successfully induced into osteogenesis. ALP staining, von Kossa staining and alizarin red staining showed positive results. The expressions of ALP, OCN and OPN were detected in ASCs after cultivation in osteogenic medium. Extensive new bone was observed in the defects transplanted with DBM-ASCs composites. Conclusion: ASCs have the potential to differentiate into osteogenic lineage and DBM-ASCs constructs are a promising method for regeneration in bone defects. Key words: Adipose tissue; Bone regeneration; Osteogenesis

  6. Natural history of the classical form of primary growth hormone (GH) resistance (Laron syndrome).

    Science.gov (United States)

    Laron, Z

    1999-04-01

    A description of the clinical, biochemical and endocrinological features of the classical form of the syndrome of primary growth hormone (GH) resistance (Laron syndrome) is presented including the progressive changes during follow-up from infancy into adulthood. The main diagnostic features are: severe growth retardation, acromicria, small gonads and genitalia, and obesity. Serum GH levels are elevated and insulin-like growth factor-I (IGF-I) values are low and do not rise upon stimulation by exogenous hGH. The pathogenesis of this syndrome is due to various molecular defects from exon deletion to nonsense, frameshift, splice and missense mutations in the GH receptor (GH-R) gene or in its post-receptor pathways.

  7. Creation and annealing of metastable defect states in CH3NH3PbI3 at low temperatures

    Science.gov (United States)

    Lang, F.; Shargaieva, O.; Brus, V. V.; Rappich, J.; Nickel, N. H.

    2018-02-01

    Methylammonium lead iodide (CH3NH3PbI3), an organic-inorganic perovskite widely used for optoelectronic applications, is known to dissociate under illumination with light at photon energies around 2.7 eV and higher. Here, we show that photo-induced dissociation is not limited to ambient temperatures but can be observed even at 5 K. The photo-induced dissociation of N-H bonds results in the formation of metastable states. Photoluminescence (PL) measurements reveal the formation of defect states that are located 100 meV within the bandgap. This is accompanied by a quenching of the band-to-band PL by one order of magnitude. Defect generation is reversible and annealing at 30 K recovers the band-to-band PL, while the light-induced defect states disappear concurrently.

  8. Nonlinear elastic wave spectroscopy in symbiosis with time reversal for localization of defects: TR-NEWS

    Czech Academy of Sciences Publication Activity Database

    Dos Santos, S.; Vejvodová, Šárka; Převorovský, Zdeněk

    2009-01-01

    Roč. 19, č. 2 (2009), s. 14-14 ISSN 1213-3825. [NDT in PROGRESS. 12.11.2009-14.11.2009, Praha] R&D Projects: GA ČR GA106/07/1393; GA MPO(CZ) FR-TI1/274 Institutional research plan: CEZ:AV0Z20760514 Keywords : nonlinear elastic wave spectroscopy (NEWS) * ESAM * time reversal (TR) * TR-NEWS imaging * tomography * DORT Subject RIV: BI - Acoustics

  9. Managing Reverse Logistics or Reversing Logistics Management?

    OpenAIRE

    Brito, Marisa

    2004-01-01

    textabstractIn the past, supply chains were busy fine-tuning the logistics from raw material to the end customer. Today an increasing flow of products is going back in the chain. Thus, companies have to manage reverse logistics as well.This thesis contributes to a better understanding of reverse logistics. The thesis brings insights on reverse logistics decision-making and it lays down theoretical principles for reverse logistics as a research field.In particular it puts together a framework ...

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  11. Skeletal Muscle Insulin Resistance in Endocrine Disease

    Directory of Open Access Journals (Sweden)

    Melpomeni Peppa

    2010-01-01

    Full Text Available We summarize the existing literature data concerning the involvement of skeletal muscle (SM in whole body glucose homeostasis and the contribution of SM insulin resistance (IR to the metabolic derangements observed in several endocrine disorders, including polycystic ovary syndrome (PCOS, adrenal disorders and thyroid function abnormalities. IR in PCOS is associated with a unique postbinding defect in insulin receptor signaling in general and in SM in particular, due to a complex interaction between genetic and environmental factors. Adrenal hormone excess is also associated with disrupted insulin action in peripheral tissues, such as SM. Furthermore, both hyper- and hypothyroidism are thought to be insulin resistant states, due to insulin receptor and postreceptor defects. Further studies are definitely needed in order to unravel the underlying pathogenetic mechanisms. In summary, the principal mechanisms involved in muscle IR in the endocrine diseases reviewed herein include abnormal phosphorylation of insulin signaling proteins, altered muscle fiber composition, reduced transcapillary insulin delivery, decreased glycogen synthesis, and impaired mitochondrial oxidative metabolism.

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

    International Nuclear Information System (INIS)

    Junkes, Alexandra

    2011-10-01

    rich material the defect transforms (V 3 activation energy for migration E a = 1.77 ± 0.08 eV) to the L defect, which can be assigned to the V 3 O defect. In the second part of this work, it is demonstrated that the radiation induced effective doping concentration can be attributed to the generation of three deep acceptors (H(116K), H(140K), H(151K)), two donors (BD defect and E(30K)) and the vacancyphosphorus defect VP. The reverse annealing of the effective doping concentration is presented for samples irradiated with neutrons for fluences up to Φ=10 15 cm -2 . From defect concentrations it is possible to reproduce the effective doping concentration as extracted from capacitance-voltage characteristics. The last part of this work deals with the characterisation of Float Zone pad sensors in the frame of the CMS tracker upgrade programme. Due to a new production process, several material defects were introduced in the sensors. They explain unexpected electrical properties in thin sensors. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

    Junkes, Alexandra

    2011-10-15

    exhibits a bistability, as does the leakage current. In oxygen rich material the defect transforms (V{sub 3} activation energy for migration E{sub a} = 1.77 {+-} 0.08 eV) to the L defect, which can be assigned to the V{sub 3}O defect. In the second part of this work, it is demonstrated that the radiation induced effective doping concentration can be attributed to the generation of three deep acceptors (H(116K), H(140K), H(151K)), two donors (BD defect and E(30K)) and the vacancyphosphorus defect VP. The reverse annealing of the effective doping concentration is presented for samples irradiated with neutrons for fluences up to {phi}=10{sup 15} cm{sup -2}. From defect concentrations it is possible to reproduce the effective doping concentration as extracted from capacitance-voltage characteristics. The last part of this work deals with the characterisation of Float Zone pad sensors in the frame of the CMS tracker upgrade programme. Due to a new production process, several material defects were introduced in the sensors. They explain unexpected electrical properties in thin sensors. (orig.)

  14. Dirichlet topological defects

    International Nuclear Information System (INIS)

    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

  15. Reverse total shoulder glenoid baseplate stability with superior glenoid bone loss.

    Science.gov (United States)

    Martin, Elise J; Duquin, Thomas R; Ehrensberger, Mark T

    2017-10-01

    Superior wear of the glenoid bone is common in patients with rotator cuff arthropathy. This can become a treatment challenge for patients who require shoulder arthroplasty. In reverse shoulder arthroplasty (RSA), glenoid bone loss may affect the stability of baseplate fixation. The primary purpose of this biomechanical laboratory study was to assess the initial fixation stability of RSA glenosphere baseplates in the presence of variable amounts of superior glenoid bone loss. High-density solid rigid polyurethane foam (30 pounds/cubic foot) was machined to model the glenoid with variable superior defects that provided different levels of support (100%, 90%, 75%, and 50%) for the glenosphere baseplate. The samples were cyclically loaded (0-750 N at 1 Hz for 5000 cycles) at a 60° glenohumeral angle. The micromotion and migration of the baseplate were calculated from displacement data captured during the loading tests with an array of 3 linear variable differential transformers mounted around the baseplate. Micromotion was significantly greater in samples with 50% defects compared with those with smaller defects. Migration was significantly greater after testing for all defect sizes. Initial fixation of RSA glenosphere baseplates was significantly reduced in models with 50% bone loss on the superior edge compared with models with less bone loss in this high-density bone foam model. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  16. Is there any advantage to the acquisition of 24-hour thallium images, in the presence of persistent perfusion defects at 4 h after reinjection?

    Science.gov (United States)

    Bobba, K; Botvinick, E H; Sciammarella, M G; Starsken, N F; Zhu, Y Y; Lapidus, A; Dae, M W

    1998-05-01

    We determined the incidence of delayed 24-h reversibility post thallium-201 reinjection and imaging at 4 h, as well as the prognostic and significance of such delayed reversibility. We studied 46 consecutive patients with persistent thallium-201 perfusion or incompletely reversible single-photon emission tomography (SPET) perfusion defects acquired within 10 min after reinjection performed 4 h after stress. In 38 of 46 patients (82%) 24-h images showed no further reversibility beyond the post-reinjection 4-h study (group A). Eight of 46 patients (17%) demonstrated reversibility on 24-h imaging (group B). Of these eight, three patients showed no improvement compared with the post-stress images, with a mean perfusion score of the abnormal segments of 1. 25+/-0.50 on the 4-h images, and of 3.00 on the 24-h images, where normal is 4. Four patients presented with nine mixed regions. Four of these regions showed an improvement in the mean perfusion score of 2.50+/-0.58 on 4- and 24-h images. Two of them, with moderate/severe defects, demonstrated complete reversibility at 4-h post-reinjection imaging. In addition, five other regions presented no improvement at 4-h imaging, but showed an improvement in the mean perfusion score from 0.80+/-0.84 at 4-h to 3.30+/-0.89 at 24-h imaging. Two of these regions in one patient showed a severe perfusion score of 0 at 4 h, and complete reversibility at 24 hours, with a mean score improvement of 4. Another patient had three severe perfusion defects; two of them redistributed partially at 4 h and completely at 24 h. The remaining segment with a perfusion score of 0 at 4 h, presented complete reversibility with a score of 4 at 24 h. Two (4%) patients revealed significant reversibility at 24 h in a region that was severely underperfused after post-reinjection imaging at 4 h. Among group B patients, 75% (6/8) had recent acute ischemic syndrome, compared with only 13% (5/38) in group A (P = 0. 001). Among 11 patients with unstable angina

  17. Synthetic lethality between gene defects affecting a single non-essential molecular pathway with reversible steps.

    Directory of Open Access Journals (Sweden)

    Andrei Zinovyev

    2013-04-01

    Full Text Available Systematic analysis of synthetic lethality (SL constitutes a critical tool for systems biology to decipher molecular pathways. The most accepted mechanistic explanation of SL is that the two genes function in parallel, mutually compensatory pathways, known as between-pathway SL. However, recent genome-wide analyses in yeast identified a significant number of within-pathway negative genetic interactions. The molecular mechanisms leading to within-pathway SL are not fully understood. Here, we propose a novel mechanism leading to within-pathway SL involving two genes functioning in a single non-essential pathway. This type of SL termed within-reversible-pathway SL involves reversible pathway steps, catalyzed by different enzymes in the forward and backward directions, and kinetic trapping of a potentially toxic intermediate. Experimental data with recombinational DNA repair genes validate the concept. Mathematical modeling recapitulates the possibility of kinetic trapping and revealed the potential contributions of synthetic, dosage-lethal interactions in such a genetic system as well as the possibility of within-pathway positive masking interactions. Analysis of yeast gene interaction and pathway data suggests broad applicability of this novel concept. These observations extend the canonical interpretation of synthetic-lethal or synthetic-sick interactions with direct implications to reconstruct molecular pathways and improve therapeutic approaches to diseases such as cancer.

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

    International Nuclear Information System (INIS)

    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

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

    Directory of Open Access Journals (Sweden)

    Hee Jin Shim

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

  20. Neural Tube Defects

    Science.gov (United States)

    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 ...

  1. Reversible switching in self-assembled monolayers of azobenzene thiolates on Au (111) probed by threshold photoemission

    Energy Technology Data Exchange (ETDEWEB)

    Heinemann, Nils, E-mail: heinemann@physik.uni-kiel.de [Institut fuer Experimentelle und Angewandte Physik, Christian-Albrechts-Universitaet zu Kiel, Leibnizstr. 19, 24098 Kiel (Germany); Grunau, Jan; Leissner, Till; Andreyev, Oleksiy; Kuhn, Sonja; Jung, Ulrich [Institut fuer Experimentelle und Angewandte Physik, Christian-Albrechts-Universitaet zu Kiel, Leibnizstr. 19, 24098 Kiel (Germany); Zargarani, Dordaneh; Herges, Rainer [Otto-Diels-Institut fuer Organische Chemie, Christian-Albrechts-Universitaet zu Kiel, Otto-Hahn-Platz 4, 24098 Kiel (Germany); Magnussen, Olaf; Bauer, Michael [Institut fuer Experimentelle und Angewandte Physik, Christian-Albrechts-Universitaet zu Kiel, Leibnizstr. 19, 24098 Kiel (Germany)

    2012-06-19

    Highlights: Black-Right-Pointing-Pointer Photoelectron spectroscopy of liquid phase prepared SAMs of azobenzene derivative. Black-Right-Pointing-Pointer Photo-induced reversible switching in densely packed SAM is monitored. Black-Right-Pointing-Pointer Maximum density of switched molecules in SAM is derived from photoemission data. Black-Right-Pointing-Pointer Switching reaction only enabled at defects sites within the molecular layer. - Abstract: The reversible photo- and thermally activated isomerization of the molecular switch 3-(4-(4-Hexyl-phenylazo)-phenoxy)-propane-1-thiol (ABT, short for AzoBenzeneThiol) deposited by self-assembly from solution on Au (111) was studied using laser-based photoelectron spectroscopy. Differences in the molecular dipole moment characteristic for the trans and the cis isomer of ABT were monitored via changes in the sample work function, accessible by detection of the threshold energy for photoemission. A quantitative analysis of our data shows that the fraction of molecules within the densely packed monolayer that undergoes a switching process is of the order of 1%. This result indicates the relevance of substrate and film defects required to overcome the steric or electronic hindrance of the isomerization reaction in a densely packed monolayer.

  2. Reverse Logistics

    OpenAIRE

    Kulikova, Olga

    2016-01-01

    This thesis was focused on the analysis of the concept of reverse logistics and actual reverse processes which are implemented in mining industry and finding solutions for the optimization of reverse logistics in this sphere. The objective of this paper was the assessment of the development of reverse logistics in mining industry on the example of potash production. The theoretical part was based on reverse logistics and mining waste related literature and provided foundations for further...

  3. Electric-dipole effect of defects on the energy band alignment of rutile and anatase TiO₂.

    Science.gov (United States)

    Zhang, Daoyu; Yang, Minnan; Dong, Shuai

    2015-11-21

    Titanium dioxide materials have been studied intensively and extensively for photocatalytic applications. A long-standing open question is the energy band alignment of rutile and anatase TiO2 phases, which can affect the photocatalytic process in the composite system. There are basically two contradictory viewpoints about the alignment of these two TiO2 phases supported by the respective experiments: (1) straddling type and (2) staggered type. In this work, our DFT plus U calculations show that the perfect rutile(110) and anatase(101) surfaces have the straddling type band alignment, whereas the surfaces with defects can turn the band alignment into the staggered type. The electric dipoles induced by defects are responsible for the reversal of band alignment. Thus the defects introduced during the preparation and post-treatment processes of materials are probably the answer to the above open question regarding the band alignment, which can be considered in real practice to tune the photocatalytic activity of materials.

  4. An integrated conceptual framework for selecting reverse logistics providers in the presence of vagueness

    Science.gov (United States)

    Fırdolaş, Tugba; Önüt, Semih; Kongar, Elif

    2005-11-01

    In recent years, relating organization's attitude towards sustainable development, environmental management is gaining an increasing interest among researchers in supply chain management. With regard to a long term requirement of a shift from a linear economy towards a cycle economy, businesses should be motivated to embrace change brought about by consumers, government, competition, and ethical responsibility. To achieve business goals and objectives, a company must reply to increasing consumer demand for "green" products and implement environmentally responsible plans. Reverse logistics is an activity within organizations delegated to the customer service function, where customers with warranted or defective products would return them to their supplier. Emergence of reverse logistics enables to provide a competitive advantage and significant return on investment with an indirect effect on profitability. Many organizations are hiring third-party providers to implement reverse logistics programs designed to retain value by getting products back. Reverse logistics vendors play an important role in helping organizations in closing the loop for products offered by the organizations. In this regard, the selection of third-party providers issue is increasingly becoming an area of reverse logistics concept and practice. This study aims to assist managers in determining which third-party logistics provider to collaborate in the reverse logistics process with an alternative approach based on an integrated model using neural networks and fuzzy logic. An illustrative case study is discussed and the best provider is identified through the solution of this model.

  5. Volumetric Analysis of Alveolar Bone Defect Using Three-Dimensional-Printed Models Versus Computer-Aided Engineering.

    Science.gov (United States)

    Du, Fengzhou; Li, Binghang; Yin, Ningbei; Cao, Yilin; Wang, Yongqian

    2017-03-01

    Knowing the volume of a graft is essential in repairing alveolar bone defects. This study investigates the 2 advanced preoperative volume measurement methods: three-dimensional (3D) printing and computer-aided engineering (CAE). Ten unilateral alveolar cleft patients were enrolled in this study. Their computed tomographic data were sent to 3D printing and CAE software. A simulated graft was used on the 3D-printed model, and the graft volume was measured by water displacement. The volume calculated by CAE software used mirror-reverses technique. The authors compared the actual volumes of the simulated grafts with the CAE software-derived volumes. The average volume of the simulated bone grafts by 3D-printed models was 1.52 mL, higher than the mean volume of 1.47 calculated by CAE software. The difference between the 2 volumes was from -0.18 to 0.42 mL. The paired Student t test showed no statistically significant difference between the volumes derived from the 2 methods. This study demonstrated that the mirror-reversed technique by CAE software is as accurate as the simulated operation on 3D-printed models in unilateral alveolar cleft patients. These findings further validate the use of 3D printing and CAE technique in alveolar defect repairing.

  6. On holographic defect entropy

    International Nuclear Information System (INIS)

    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

  7. Electric field effects on radiation defects annealing in p-InP

    International Nuclear Information System (INIS)

    Sibille, A.

    1983-01-01

    Annealing experiments have been performed on electron irradiated Schottky diodes on p-InP. They show a strong influence of the applied reverse bias during annealing on the recovery of the free holes concentration, as well as on the disappearance of the dominant radiation induced hole traps detected by deep level transient spectroscopy (DLTS). Compensating defects are observed to drift under the action of the electric field and accumulate at the edge of the depleted zone, while the main hole traps created by the irradiation anneal faster when empty of holes or subjected to an electric field. (author)

  8. Defect-dependent elasticity: Nanoindentation as a probe of stress state

    International Nuclear Information System (INIS)

    Jarausch, K. F.; Kiely, J. D.; Houston, J. E.; Russell, P. E.

    2000-01-01

    Using an interfacial force microscope, the measured elastic response of 100-nm-thick Au films was found to be strongly correlated with the films' stress state and thermal history. Large, reversible variations (2x) of indentation modulus were recorded as a function of applied stress. Low-temperature annealing caused permanent changes in the films' measured elastic properties. The measured elastic response was also found to vary in close proximity to grain boundaries in thin films and near surface steps on single-crystal surfaces. These results demonstrate a complex interdependence of stress state, defect structure, and elastic properties in thin metallic films. (c) 2000 Materials Research Society

  9. RECONSTRUCTION OF POST ELECTRIC BURN DEFECTS OF UPPER LIMB WITH DIFFERENT FLAPS

    Directory of Open Access Journals (Sweden)

    Satyajit

    2015-08-01

    Full Text Available INTRODUCTION: P ost electric burn defects are difficult to manage due to deep injury involving all the structures up to bony level. A good vascularized flap is required to resurface the defect for preventing the complication and for reconstruction of involved structures. AIM: Resurfacing the post electric burn defect with different flaps according to need of the defect. MATERIAL AND METHOD: All patients of electric burn hand and fore arm defect admitted to burn, p lastic and reconstructi ve department of SCB Medical College &hospital, Cuttack between January 2012 to December 2012 were included in the study. During this period the patients were followed up at weekly interval for first 2 month, then at 1 monthly interv al for next 6 - 8 month. OBSERVATION: Out of 40 cases of post electric burn forearm and hand reconstruction, 10 cases underwent groin flap cover, 6 cases underwent abdominal flap cover, 5 cases underwent cross finger flap cover 5 cases underwent free antero lateral thigh flap cover, 4 cases underwent free latissimus dorsi flap cover, 5 cases underwent first dorsal metacarpal artery flap cover, 5 cases reverse radial forearm flap cover. All the defects were resurfaced successfully with flaps. Four had marginal necrosis and six had wound infection. Eventually all flaps settled well without further intervention. Due to involvement of all important tendons & nerves, functional outcome is guarded. DISCUSSION: Hand and forearm are most commonly and most severely aff ected in electric burn injury because they are mostly first part of body to come in contact with electric circuit. Even though at initial part the injury appears to be superficial, deepe r structures like bone, tendon and neurovascular bundles are affected requiring flap cover for future reconstruction of these structures to get functional and sensate hand. CONCLUSION: Reconstruction of post electric burn defect of distal forearm and hand represents great challenge due to

  10. Diode characteristics and residual deep-level defects of p+n abrupt junctions fabricated by rapid thermal annealing of boron implanted silicon

    International Nuclear Information System (INIS)

    Usami, A.; Katayama, M.; Wada, T.; Tokuda, Y.

    1987-01-01

    p + n diodes were fabricated by rapid thermal annealing (RTA) of boron implanted silicon in the annealing temperature range 700-1100 0 C for around 7 s, and the RTA temperature dependence of electrical characteristics of these diodes was studied. Deep-level transient spectroscopy (DLTS) measurements were made to evaluate residual deep-level defects in the n-type bulk. Three electron traps were observed in p + n diodes fabricated by RTA at 700 0 C. It was considered that these three traps were residual point defects near the tail of the implantation damage after RTA. Residual defect concentrations increased in the range 700-900 0 C and decreased in the range 1000-1100 0 C. The growth of defects in the bulk was ascribed to the diffusion of defects from the implanted layer during RTA. Concentrations of electron traps observed in p + n diodes fabricated by RTA at 1100 0 C were approx. 10 12 cm -3 . It was found that these residual deep-level defects observed by DLTS were inefficient generation-recombination centres since the reverse current was independent of the RTA temperatures. (author)

  11. Defects in semiconductors

    CERN Document Server

    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

  12. Repair of full-thickness articular cartilage defect using stem cell-encapsulated thermogel.

    Science.gov (United States)

    Zhang, Yanbo; Zhang, Jin; Chang, Fei; Xu, Weiguo; Ding, Jianxun

    2018-07-01

    Cartilage defect repair by hydrogel-based tissue engineering is becoming one of the most potential treatment strategies. In this work, a thermogel of triblock copolymer poly(lactide-co-glycolide)-block-poly(ethylene glycol)-block-poly(lactide-co-glycolide) (PLGA-PEG-PLGA) was prepared as scaffold of bone marrow mesenchymal stem cells (BMMSCs) for repair of full-thickness articular cartilage defect. At first, the copolymer solution showed a reversible sol-gel transition at physiological temperature range, and the mechanical properties of such thermogel were high enough to support the repair of cartilage. Additionally, excellent biodegradability and biocompatibility of the thermogel were demonstrated. By implanting the BMMSC-encapsulated thermogel into the full-thickness articular cartilage defect (5.0 mm in diameter and 4.0 mm in depth) in the rabbit, it was found that the regenerated cartilage integrated well with the surrounding normal cartilage and subchondral bone at 12 weeks post-surgery. The upregulated expression of glycosaminoglycan and type II collagen in the repaired cartilage, and the comparable biomechanical properties with normal cartilage suggested that the cell-encapsulated PLGA-PEG-PLGA thermogel had great potential in serving as the promising scaffold for cartilage regeneration. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Reverse-namaskar: A new sign in Ehlers-Danlos syndrome: A family pedigree study of four generations

    Directory of Open Access Journals (Sweden)

    Premalatha S

    2010-01-01

    Full Text Available Ehlers-Danlos Syndrome (EDS is a rare group of inheritable connective tissue disorder of defective collagen. Skin, joints and blood vessels are most commonly affected. Clinical signs such as Gorlin sign and Metenier sign have been described in this syndrome. We report another new clinical sign called ′Reverse-Namaskar′ sign as an important clinical finding in EDS, based on the family pedigree study of the proband.

  14. Reversible pressure-induced crystal-amorphous structural transformation in ice Ih

    Science.gov (United States)

    English, Niall J.; Tse, John S.

    2014-08-01

    Molecular dynamics (MD) simulation of depressurised high-density amorphous ice (HDA) at 80 K and at negative pressures has been performed. Over several attempts, HDA recrystallised to a form close to hexagonal ice Ih, albeit with some defects. The results support the hypothesis that compression of ice-Ih to HDA is a reversible first-order phase transition, with a large hysteresis. Therefore, it would appear that LDA is not truly amorphous. The elastic energy estimated from the area of the hysteresis loop is ca. 4.5 kJ/mol, in some way consistent with experimentally-determined accumulated successive heats of transformations from recovered HDA → ice Ih.

  15. Hyperbaric oxygen therapy and surgical delay improve flap survival of reverse pedicle flaps for lower third leg and foot reconstruction

    Directory of Open Access Journals (Sweden)

    Pradeoth Mukundan Korambayil

    2015-06-01

    Full Text Available Aim: The purpose of the study is to present a management protocol for various types of soft tissue defects of the distal third region of leg and foot treated with pedicle flaps, by including hyperbaric oxygen (HBO therapy in the treatment regimen with flap delay. Methods: We present a prospective study of 23 patients with various types of soft tissue defects of the foot, and lower third of leg managed in our institution from December 2012 to December 2013. All soft tissue defects were treated by a reverse pedicle flap. Twelve patients were managed with flap delay with HBO therapy and 11 patients with immediate flaps without HBO therapy. The postoperative period, hospital course, and follow-up were documented. Results: Of 12 patients with flap delay and HBO, 10 patients did not suffer any complications secondary to flap transfer. One patient had discoloration of the tip of the flap, which settled without the intervention, and 1 patient had recurrent abscess formation, which required debridement and closure. Of 11 patients with direct transfer, 6 patients presented with complications including flap congestion, partial flap loss, and tip necrosis, which required secondary intervention. Conclusion: HBO therapy is a useful adjunct in flap delay of the reverse pedicle flap for soft tissue reconstruction of the lower third of the leg and foot regions.

  16. Surface structure of YBa2Cu3O7-x probed by reversed-bias scanning tunneling microscopy

    International Nuclear Information System (INIS)

    Edwards, H.L.; Markert, J.T.; Lozanne, A.L.d.

    1994-01-01

    We report the results of scanning tunneling microscopy studies on high-quality single crystals of YBa 2 Cu 3 O 7-x (YBCO) which were cleaved along a basal plane in situ at 20 K prior to measurement. The initial results of a systematic study of the YBCO surface are presented. Reversed-bias images of the CuO chain layer reveal modulations 3.3±0.3|b|=1.3±0.1 nm in wavelength which change phase by 180 degree under bias polarity reversal along solid chains, and are invariant under bias polarity reversal at a point defect. Regions of sharp unit-cell-sized square corrugations with disordered islands are also observed. We interpret these new results in terms of our previous model [H. L. Edwards, J. T. Markert, and A. L. de Lozanne, Phys. Rev. Lett. 69, 2967 (1992)] of the cleaved YBCO surface

  17. Boron Removal from Seawater by Thin-Film Composite Reverse Osmosis Membranes

    KAUST Repository

    Al Sunbul, Yasmeen

    2018-04-01

    Reverse Osmosis membranes have been successfully proven to remove almost 99% of chemicals dissolved in seawater. However, removal of certain trace elements, such as boron is challenging and relatively low for seawater reverse osmosis desalination plants compared to thermal desalination plants. Boron is naturally occurring and is present in seawater at an average concentration of 4.5-5 mg/L. While boron is a vital element, its toxicity has been proven on crops, animals and possibly humans. Additionally, boron should be removed to comply with the current guideline value of 0.5 mg/L, for drinking water, issued by the World Health Organization (WHO), which is barely attained by a single-pass process seawater reverse osmosis plant. Currently, multipass reverse osmosis membrane operations with pH modifications are the only valid method for boron removal. However, this is not economically efficient as it requires higher energy and chemicals consumptions. The objective of this study was to investigate boron removal by commercial TFC RO membranes in addition to custom-made KAUST-synthesized TFC membrane. Five membrane samples were examined: Toray, Sepro, Koch, and KAUST in-house synthesized membrane. Three different feed pH conditions were used: pH6, pH8, and pH10. Filtration experiments were conducted in two parts. In experiment 1, all five membranes were examined for boron rejection in a dead-end permeation system, whereas in experiment 2 the two membranes with the highest boron rejection from experiment 1 were tested in a cross-flow system. Permeate and feed samples were taken continuously and analyzed for boron concentration, rejection calculation. Membrane surfaces were characterized according to hydrophilicity, roughness and surface charge. The results showed for all the tested membranes that boron rejection increased as the feed pH increased. KAUST, defect-free TFC, showed the highest performance for boron rejection for all pH conditions, although, it shows the

  18. Fibrous metaphyseal defects

    International Nuclear Information System (INIS)

    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)

  19. 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: two case reports and a review of the literature.

    Science.gov (United States)

    Bjørsum-Meyer, Thomas; Herlin, Morten; Qvist, Niels; Petersen, Michael B

    2016-12-21

    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. Our first case was a white girl delivered by caesarean section at 37 weeks of gestation; our second case was a white girl born at a gestational age of 40 weeks. A co-occurrence of vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association and Mayer-Rokitansky-Küster-Hauser syndrome was diagnosed in both cases. We performed a systematic literature search in PubMed ((VACTERL) OR (VATER)) AND ((MRKH) OR (Mayer-Rokitansky-Küster-Hauser) OR (mullerian agenesis) OR (mullerian aplasia) OR (MURCS)) without limitations. A similar search was performed in Embase and the Cochrane library. We added two cases from our local center. All cases (n = 9) presented with anal atresia and renal defect. Vertebral defects were present in eight patients. Rectovestibular fistula was confirmed in seven patients. Along with the uterovaginal agenesis, fallopian tube aplasia appeared in five of nine cases and in two cases ovarian involvement also existed. The co-occurrence of the vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal

  20. ILT based defect simulation of inspection images accurately predicts mask defect printability on wafer

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    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.

  2. Synthetic Defects for Vibrothermography

    Science.gov (United States)

    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.

  3. Both nuclear and cytoplasmic components are defective in oocytes of the B6.Y(TIR) sex-reversed female mouse.

    Science.gov (United States)

    Amleh, A; Smith, L; Chen, H; Taketo, T

    2000-03-15

    In the mammalian gonadal primordium, activation of the Sry gene on the Y chromosome initiates a cascade of genetic events leading to testicular organization whereas its absence results in ovarian differentiation. An exception occurs when the Y chromosome of Mus musculus domesticus from Tirano, Italy (Y(TIR)), is placed on the C57BL/6J (B6) genetic background. The B6.Y(TIR) progeny develop only ovaries or ovotestes despite Sry transcription in fetal life. Consequently, the XY offspring with bilateral ovaries develop into apparently normal females, but their eggs fail to develop after fertilization. Our previous studies have shown that the primary cause of infertility can be attributed to oocytes rather than their surrounding somatic cells in the XY ovary. This study attempted to identify the defects in oocytes from the B6.Y(TIR) female mouse. We examined the developmental potential of embryos from XY and XX females after exchanging their nuclear components by microsurgery following in vitro maturation and fertilization. The results suggest that both nuclear and cytoplasmic components are defective in oocytes from XY females. In the XY fetal ovary, most germ cells entered meiosis and their autosomes appeared to synapse normally while the X and Y chromosomes remained unpaired during meiotic prophase. This lack of X-Y pairing probably caused aneuploidy in some secondary oocytes following in vitro maturation. However, normal numbers of chromosomes in the rest of the secondary oocytes indicate that aneuploidy alone can not explain the nuclear defect in oocytes. Copyright 2000 Academic Press.

  4. Large effect of columnar defects on the thermodynamic properties of Bi2Sr2CaCu2O8 single crystals

    Science.gov (United States)

    van der Beek, C. J.; Konczykowski, M.; Li, T. W.; Kes, P. H.; Benoit, W.

    1996-07-01

    The introduction of columnar defects by irradiation with 5.8-GeV Pb ions is shown to affect significantly the reversible magnetic properties of Bi2Sr2CaCu2O8+δ single crystals. Notably, the suppression of superconducting fluctuations on length scales greater than the separation between columns leads to the disappearance of the ``crossing point'' in the critical fluctuation regime. At lower temperatures, the strong modification of the vortex energy due to pinning leads to an important change of the reversible magnetization. The analysis of the latter permits the direct determination of the pinning energy.

  5. Reversible Thermoset Adhesives

    Science.gov (United States)

    Mac Murray, Benjamin C. (Inventor); Tong, Tat H. (Inventor); Hreha, Richard D. (Inventor)

    2016-01-01

    Embodiments of a reversible thermoset adhesive formed by incorporating thermally-reversible cross-linking units and a method for making the reversible thermoset adhesive are provided. One approach to formulating reversible thermoset adhesives includes incorporating dienes, such as furans, and dienophiles, such as maleimides, into a polymer network as reversible covalent cross-links using Diels Alder cross-link formation between the diene and dienophile. The chemical components may be selected based on their compatibility with adhesive chemistry as well as their ability to undergo controlled, reversible cross-linking chemistry.

  6. Reverse saphenous conduit flap in small animals: Clinical applications and outcomes

    Directory of Open Access Journals (Sweden)

    Ross C. Elliott

    2014-08-01

    Full Text Available Due to the lack of skin elasticity defects of the distal hind limb can be a challenge to close. This article assesses a well-described, but completely under-used technique for closure of wounds on the distal tarsus. The technique was used with good success in six cases presenting to the Bryanston Veterinary Hospital with a wide range of underlying pathology ranging from trauma to neoplastic disease of the tarsus. All six cases were treated with a reverse saphenous conduit flap and two of them underwent radiation therapy with no adverse side effects. All cases showed excellent results with a very low degree of flap necrosis that never exceeded 15% of the total flap area. This skin flap provides an excellent treatment method that is reliable in closure of defects of the distal tarsus with few adverse effects. To the author’s knowledge there has been only one previously published report on the clinical use of this type of skin flap,even though the flap is well described in most texts.

  7. Feline leukemia virus infection requires a post-receptor binding envelope-dependent cellular component.

    Science.gov (United States)

    Hussain, Naveen; Thickett, Kelly R; Na, Hong; Leung, Cherry; Tailor, Chetankumar S

    2011-12-01

    Gammaretrovirus receptors have been suggested to contain the necessary determinants to mediate virus binding and entry. Here, we show that murine NIH 3T3 and baby hamster kidney (BHK) cells overexpressing receptors for subgroup A, B, and C feline leukemia viruses (FeLVs) are weakly susceptible (10(1) to 10(2) CFU/ml) to FeLV pseudotype viruses containing murine leukemia virus (MLV) core (Gag-Pol) proteins, whereas FeLV receptor-expressing murine Mus dunni tail fibroblast (MDTF) cells are highly susceptible (10(4) to 10(6) CFU/ml). However, NIH 3T3 cells expressing the FeLV subgroup B receptor PiT1 are highly susceptible to gibbon ape leukemia virus pseudotype virus, which differs from the FeLV pseudotype viruses only in the envelope protein. FeLV resistance is not caused by a defect in envelope binding, low receptor expression levels, or N-linked glycosylation. Resistance is not alleviated by substitution of the MLV core in the FeLV pseudotype virus with FeLV core proteins. Interestingly, FeLV resistance is alleviated by fusion of receptor-expressing NIH 3T3 and BHK cells with MDTF or human TE671 cells, suggesting the absence of an additional cellular component in NIH 3T3 and BHK cells that is required for FeLV infection. The putative FeLV-specific cellular component is not a secreted factor, as MDTF conditioned medium does not alleviate the block to FeLV infection. Together, our findings suggest that FeLV infection requires an additional envelope-dependent cellular component that is absent in NIH 3T3 and BHK cells but that is present in MDTF and TE671 cells.

  8. Zero field reversal probability in thermally assisted magnetization reversal

    Science.gov (United States)

    Prasetya, E. B.; Utari; Purnama, B.

    2017-11-01

    This paper discussed about zero field reversal probability in thermally assisted magnetization reversal (TAMR). Appearance of reversal probability in zero field investigated through micromagnetic simulation by solving stochastic Landau-Lifshitz-Gibert (LLG). The perpendicularly anisotropy magnetic dot of 50×50×20 nm3 is considered as single cell magnetic storage of magnetic random acces memory (MRAM). Thermally assisted magnetization reversal was performed by cooling writing process from near/almost Curie point to room temperature on 20 times runs for different randomly magnetized state. The results show that the probability reversal under zero magnetic field decreased with the increase of the energy barrier. The zero-field probability switching of 55% attained for energy barrier of 60 k B T and the reversal probability become zero noted at energy barrier of 2348 k B T. The higest zero-field switching probability of 55% attained for energy barrier of 60 k B T which corespond to magnetif field of 150 Oe for switching.

  9. Reverse Osmosis

    Indian Academy of Sciences (India)

    many applications, one of which is desalination of seawater. The inaugural Nobel Prize in Chemistry was awarded in 1901 to van 't Hoff for his seminal work in this area. The present article explains the principle of osmosis and reverse osmosis. Osmosis and Reverse Osmosis. As the name suggests, reverse osmosis is the ...

  10. Facts about Birth Defects

    Science.gov (United States)

    ... 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 ...

  11. Defect production in ceramics

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. Defects in dilute nitrides

    International Nuclear Information System (INIS)

    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)

  13. A production inventory model with exponential demand rate and reverse logistics

    Directory of Open Access Journals (Sweden)

    Ritu Raj

    2014-08-01

    Full Text Available The objective of this paper is to develop an integrated production inventory model for reworkable items with exponential demand rate. This is a three-layer supply chain model with perspectives of supplier, producer and retailer. Supplier delivers raw material to the producer and finished goods to the retailer. We consider perfect and imperfect quality products, product reliability and reworking of imperfect items. After screening, defective items reworked at a cost just after the regular manufacturing schedule. At the beginning, the manufacturing system starts produce perfect items, after some time the manufacturing system can undergo into “out-of-control” situation from “in-control” situation, which is controlled by reverse logistic technique. This paper deliberates the effects of business strategies like optimum order size of raw material, exponential demand rate, production rate is demand dependent, idle times and reverse logistics for an integrated marketing system. Mathematica is used to develop the optimal solution of production rate and raw material order for maximum expected average profit. A numerical example and sensitivity analysis is illustrated to validate the model.

  14. Genital and Urinary Tract Defects

    Science.gov (United States)

    ... 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 ...

  15. Multiple splicing defects in an intronic false exon.

    Science.gov (United States)

    Sun, H; Chasin, L A

    2000-09-01

    Splice site consensus sequences alone are insufficient to dictate the recognition of real constitutive splice sites within the typically large transcripts of higher eukaryotes, and large numbers of pseudoexons flanked by pseudosplice sites with good matches to the consensus sequences can be easily designated. In an attempt to identify elements that prevent pseudoexon splicing, we have systematically altered known splicing signals, as well as immediately adjacent flanking sequences, of an arbitrarily chosen pseudoexon from intron 1 of the human hprt gene. The substitution of a 5' splice site that perfectly matches the 5' consensus combined with mutation to match the CAG/G sequence of the 3' consensus failed to get this model pseudoexon included as the central exon in a dhfr minigene context. Provision of a real 3' splice site and a consensus 5' splice site and removal of an upstream inhibitory sequence were necessary and sufficient to confer splicing on the pseudoexon. This activated context also supported the splicing of a second pseudoexon sequence containing no apparent enhancer. Thus, both the 5' splice site sequence and the polypyrimidine tract of the pseudoexon are defective despite their good agreement with the consensus. On the other hand, the pseudoexon body did not exert a negative influence on splicing. The introduction into the pseudoexon of a sequence selected for binding to ASF/SF2 or its replacement with beta-globin exon 2 only partially reversed the effect of the upstream negative element and the defective polypyrimidine tract. These results support the idea that exon-bridging enhancers are not a prerequisite for constitutive exon definition and suggest that intrinsically defective splice sites and negative elements play important roles in distinguishing the real splicing signal from the vast number of false splicing signals.

  16. Resistance to thyroid hormone due to defective thyroid receptor alpha.

    Science.gov (United States)

    Moran, Carla; Chatterjee, Krishna

    2015-08-01

    Thyroid hormones act via nuclear receptors (TRα1, TRβ1, TRβ2) with differing tissue distribution; the role of α2 protein, derived from the same gene locus as TRα1, is unclear. Resistance to thyroid hormone alpha (RTHα) is characterised by tissue-specific hypothyroidism associated with near-normal thyroid function tests. Clinical features include dysmorphic facies, skeletal dysplasia (macrocephaly, epiphyseal dysgenesis), growth retardation, constipation, dyspraxia and intellectual deficit. Biochemical abnormalities include low/low-normal T4 and high/high-normal T3 concentrations, a subnormal T4/T3 ratio, variably reduced reverse T3, raised muscle creatine kinase and mild anaemia. The disorder is mediated by heterozygous, loss-of-function, mutations involving either TRα1 alone or both TRα1 and α2, with no discernible phenotype attributable to defective α2. Whole exome sequencing and diagnostic biomarkers may enable greater ascertainment of RTHα, which is important as thyroxine therapy reverses some metabolic abnormalities and improves growth, constipation, dyspraxia and wellbeing. The genetic and phenotypic heterogeneity of RTHα and its optimal management remain to be elucidated. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  17. Point defects and defect clusters examined on the basis of some fundamental experiments

    International Nuclear Information System (INIS)

    Zuppiroli, L.

    1975-01-01

    On progressing from the centre of the defect to the surface the theoretical approach to a point defect passes from electronic theories to elastic theory. Experiments by which the point defect can be observed fall into two categories. Those which detect long-range effects: measurement of dimensional variations in the sample; measurement of the mean crystal parameter variation; elastic X-ray scattering near the nodes of the reciprocal lattice (Huang scattering). Those which detect more local effects: low-temperature resistivity measurement; positron capture and annihilation; local scattering far from the reciprocal lattice nodes. Experiments involving both short and long-range effects can always be found. This is the case for example with the dechanneling of α particles by defects. Certain of the experimental methods quoted above apply also to the study of point defect clusters. These methods are illustrated by some of their most striking results which over the last twenty years have refined our knowledge of point defects and defect clusters: length and crystal parameter measurements; diffuse X-ray scattering; low-temperature resistivity measurements; ion emission microscopy; electron microscopy; elastoresistivity [fr

  18. Birth Defects (For Parents)

    Science.gov (United States)

    ... 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 ...

  19. Defect of the Eyelids.

    Science.gov (United States)

    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.

  20. Managing Reverse Logistics or Reversing Logistics Management?

    NARCIS (Netherlands)

    M.P. de Brito (Marisa)

    2004-01-01

    textabstractIn the past, supply chains were busy fine-tuning the logistics from raw material to the end customer. Today an increasing flow of products is going back in the chain. Thus, companies have to manage reverse logistics as well.This thesis contributes to a better understanding of reverse

  1. Formation of topological defects

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

    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...

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

    Science.gov (United States)

    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...

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

    Science.gov (United States)

    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...

  5. Distribution of defects in wind turbine blades and reliability assessment of blades containing defects

    DEFF Research Database (Denmark)

    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...

  6. Evaluation of reversible contraceptive potential of Cordia dichotoma leaves extract

    Directory of Open Access Journals (Sweden)

    Plaban Bhattacharya

    2013-04-01

    Full Text Available Considering the safety-risk ratio of steroidal contraceptives, the present work was carried out to evaluate ethno-contraceptive use of Cordia dichotoma G. Forst., Boraginaceae, leaves (LCD. Preliminary pharmacological screening was performed on post-coital female albino rats. The leaves extract (LD50 5.50 g/kg bw showed 100% anti-implantation activity (n=10 at 800 mg/kg dose level. (2-hydroxypropyl-β-cyclodextrin (BCD was used as bioavailability enhancer to form LCD-BCD complex, characterized by DLS, SEM and XRD analyses. The LCD-BCD complex (1:1, w/w exhibited 100% pregnancy interception (n=20 at the dose level of 250 mg/kg and also showed strong estrogenic potential with a luteal phase defect. Qualitative and quantitative phytochemical analyses were carried out. The LCD extract was standardized by a validated HPTLC method and two contraceptive phytoconstituents, apigenin and luteolin were isolated. A detailed pharmacological analyses followed by chronic toxicity study were performed to predict the reversible nature of the developed phytopharmaceutical. The histological and biochemical estimations detected the reversible contraceptive potential after withdrawal. The observations suggested that the developed phyto-pharmaceutical has potential antifertility activity with safety aspects.

  7. Evaluation of reversible contraceptive potential of Cordia dichotoma leaves extract

    Directory of Open Access Journals (Sweden)

    Plaban Bhattacharya

    2013-03-01

    Full Text Available Considering the safety-risk ratio of steroidal contraceptives, the present work was carried out to evaluate ethno-contraceptive use of Cordia dichotoma G. Forst., Boraginaceae, leaves (LCD. Preliminary pharmacological screening was performed on post-coital female albino rats. The leaves extract (LD50 5.50 g/kg bw showed 100% anti-implantation activity (n=10 at 800 mg/kg dose level. (2-hydroxypropyl-β-cyclodextrin (BCD was used as bioavailability enhancer to form LCD-BCD complex, characterized by DLS, SEM and XRD analyses. The LCD-BCD complex (1:1, w/w exhibited 100% pregnancy interception (n=20 at the dose level of 250 mg/kg and also showed strong estrogenic potential with a luteal phase defect. Qualitative and quantitative phytochemical analyses were carried out. The LCD extract was standardized by a validated HPTLC method and two contraceptive phytoconstituents, apigenin and luteolin were isolated. A detailed pharmacological analyses followed by chronic toxicity study were performed to predict the reversible nature of the developed phytopharmaceutical. The histological and biochemical estimations detected the reversible contraceptive potential after withdrawal. The observations suggested that the developed phyto-pharmaceutical has potential antifertility activity with safety aspects.

  8. Generation and Characterization of a Defective HIV-1 Virus as an Immunogen for a Therapeutic Vaccine

    Science.gov (United States)

    García-Pérez, Javier; García, Felipe; Blanco, Julia; Escribà-García, Laura; Gatell, Jose Maria; Alcamí, Jose; Plana, Montserrat; Sánchez-Palomino, Sonsoles

    2012-01-01

    Background The generation of new immunogens able to elicit strong specific immune responses remains a major challenge in the attempts to obtain a prophylactic or therapeutic vaccine against HIV/AIDS. We designed and constructed a defective recombinant virus based on the HIV-1 genome generating infective but non-replicative virions able to elicit broad and strong cellular immune responses in HIV-1 seropositive individuals. Results Viral particles were generated through transient transfection in producer cells (293-T) of a full length HIV-1 DNA carrying a deletion of 892 base pairs (bp) in the pol gene encompassing the sequence that codes for the reverse transcriptase (NL4-3/ΔRT clone). The viral particles generated were able to enter target cells, but due to the absence of reverse transcriptase no replication was detected. The immunogenic capacity of these particles was assessed by ELISPOT to determine γ-interferon production in a cohort of 69 chronic asymptomatic HIV-1 seropositive individuals. Surprisingly, defective particles produced from NL4-3/ΔRT triggered stronger cellular responses than wild-type HIV-1 viruses inactivated with Aldrithiol-2 (AT-2) and in a larger proportion of individuals (55% versus 23% seropositive individuals tested). Electron microscopy showed that NL4-3/ΔRT virions display immature morphology. Interestingly, wild-type viruses treated with Amprenavir (APV) to induce defective core maturation also induced stronger responses than the same viral particles generated in the absence of protease inhibitors. Conclusions We propose that immature HIV-1 virions generated from NL4-3/ΔRT viral clones may represent new prototypes of immunogens with a safer profile and stronger capacity to induce cellular immune responses than wild-type inactivated viral particles. PMID:23144996

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

    Science.gov (United States)

    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.

  10. A Systematic Review of Outcomes and Complications of Primary Fingertip Reconstruction Using Reverse-Flow Homodigital Island Flaps.

    Science.gov (United States)

    Regmi, Subhash; Gu, Jia-xiang; Zhang, Nai-chen; Liu, Hong-jun

    2016-04-01

    Fingertip reconstruction using reverse-flow homodigital island flaps has been very popular over the years. However, the outcomes of reconstruction have not been clearly understood. In these circumstances, a systematic review of available literature is warranted. To assess the outcomes and complications of fingertip reconstruction using reverse-flow homodigital island flaps. To justify the usage of reverse-flow homodigital island flaps for fingertip reconstruction. A PubMed [MEDLINE] electronic database was searched (1985 to 15 April 2015). Retrospective case series that met the following criteria were included: (1) Study reported primary data; (2) Study included at least five cases of fingertip defects treated using reverse-flow homodigital island flaps; (3) Study reported outcomes and complications of fingertip reconstruction, either primary or delayed, using reverse-flow homodigital island flaps; (4) The study presented at least one of the following functional outcomes: Static two-point discrimination, return-to-work time, range of motion of distal interphalangeal joints; (5) The study presented at least one complication. Two review authors independently assessed search results, and two other review authors analyzed the data and resolved disagreements. The following endpoints were analyzed: survival rate of the flap, sensibility, and functional outcomes and complications. Eight studies were included in this review. The included studies were published between 1995 and 2014, and a total of 207 patients with 230 fingertip defects were reported. The overall survival rate of the flap was 98 % (including partial survival). The mean static two-point discrimination (2PD) was 7.2 mm. The average range of motion of the DIP joint was 63°. The average return-to-work time was 7 weeks after injury. On average, 2 % of the patient had complete flap necrosis, 5 % had partial flap necrosis, 4 % developed venous congestion, 4 % developed flexion contracture, and 12 % experienced

  11. PZT-Based Detection of Compactness of Concrete in Concrete Filled Steel Tube Using Time Reversal Method

    Directory of Open Access Journals (Sweden)

    Shi Yan

    2014-01-01

    Full Text Available A smart aggregate-based approach is proposed for the concrete compactness detection of concrete filled steel tube (CFST columns. The piezoceramic-based smart aggregates (SAs were embedded in the predetermined locations prior to the casting of concrete columns to establish a wave-based smart sensing system for the concrete compactness detection purpose. To evaluate the efficiency of the developed approach, six specimens of the CFST columns with the rectangular cross-section were produced by placing some artificial defects during casting of concrete for simulating various uncompacted voids such as cavities, cracks, and debond. During the test, the time reversal technology was applied to rebuild the received signals and launch the reversed signals again by SAs, to overcome the issue of the lack of the prototype. Based on the proposed nonprototype, two indices of time reversibility (TR and symmetry (SYM were applied to relatively evaluate the level of concrete compactness in the range of the two SAs. The experimental results show that the developed method can effectively detect the compactness of concrete in CFST columns.

  12. Natural defects and defects created by ionic implantation in zinc tellurium

    International Nuclear Information System (INIS)

    Roche, J.P.; Dupuy, M.; Pfister, J.C.

    1977-01-01

    Various defects have been studied in ZnTe crystals by transmission electron microscope and by scanning electron microscope in cathodo-luminescence mode: grain boundaries, sub-grain boundaries, twins. Ionic implants of boron (100 keV - 2x10 14 and 10 15 ions cm -2 ) were made on these crystals followed by isochrone annealing (30 minutes) of zinc under partial pressure at 550, 650 and 750 0 C. The nature of the defects was determined by transmission electron microscope: these are interstitial loops (b=1/3 ) the size of which varies between 20 A (non-annealed sample) and 180A (annealed at 750 0 C). The transmission electron microscope was also used to make concentration profiles of defects depending on depth. It is found that for the same implant (2x10 14 ions.cm -2 ), the defect peak moves towards the exterior of the crystal as the annealing temperature rises (400 - 1000 and 7000 A for the three annealings). These results are explained from a model which allows for the coalescence of defects and considers the surface of the sample as being the principal source of vacancies. During the annealings, the migration of vacancies brings about the gradual annihilation of the implant defects. The adjustment of certain calculation parameters on the computer result in giving 2 eV as energy value for the formation of vacancies [fr

  13. Studies of insulin resistance in congenital generalized lipodystrophy

    DEFF Research Database (Denmark)

    Søvik, O; Vestergaard, H; Trygstad, O

    1996-01-01

    suppressed lipid oxidation in the controls. It is concluded that patients with congenital generalized lipodystrophy may present severe insulin resistance with regard to hepatic glucose production as well as muscle glycogen synthesis and lipid oxidation. The results suggest a postreceptor defect in the action......, immunoreactive protein and mRNA levels. The patients had fasting hyperinsulinaemia, and the rate of total glucose disposal was severely impaired, primarily due to a decreased non-oxidative glucose metabolism. In the patient studied with muscle biopsy, the expected activation of glycogen synthase by insulin did...... not occur. In both patients there was severely increased hepatic glucose output in the basal state, suggesting a failure of insulin to suppress hepatic gluconeogenesis. During insulin infusion a substantially elevated rate of lipid oxidation remained in the patients, in contrast to the almost completely...

  14. Modeling the relationships among internal defect features and external Appalachian hardwood log defect indicators

    Science.gov (United States)

    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...

  15. Micromachining of semiconductor by femtosecond laser for integrated circuit defect analysis

    Energy Technology Data Exchange (ETDEWEB)

    Halbwax, M. [Laboratoire LP3 CNRS UMR 6182, Parc Scientifique et Technologique de Luminy, Case 917, 163 Avenue de Luminy, 13009 Marseille (France); Sarnet, T. [Laboratoire LP3 CNRS UMR 6182, Parc Scientifique et Technologique de Luminy, Case 917, 163 Avenue de Luminy, 13009 Marseille (France)], E-mail: sarnet@lp3.univ-mrs.fr; Hermann, J.; Delaporte, Ph.; Sentis, M. [Laboratoire LP3 CNRS UMR 6182, Parc Scientifique et Technologique de Luminy, Case 917, 163 Avenue de Luminy, 13009 Marseille (France); Fares, L.; Haller, G. [STMicroelectronics, 190 Avenue Celestin Coq, ZI, 13106 Rousset Cedex (France)

    2007-12-15

    The latest International Technology Roadmap for Semiconductors (ITRS) has highlighted the detection and analysis of defects in Integrated Circuits (IC) as a major challenge faced by the semiconductor industry. Advanced tools used today for defect cross sectioning include dual beams (focused ion- and electron-beam technologies) with resolution down to the sub-Angstrom level. However ion milling an IC with a FIB is time consuming because of the need to open wide cavities in front of the cross-sections that need to be analyzed. Therefore the use of a femtosecond laser as a tool for direct material removal is discussed in this paper. Experiments were performed on IC structures to reveal the different layers of fabrication: selective or total ablation can occur depending on the laser energy density, without delamination of the layers. Different laser irradiation conditions like pressure (air, vacuum), polarization, beam shaping, and scanning parameters have been used to produce different types of cavities. The femtosecond laser engraving of silicon-based structures could be useful for cross-sectioning devices but also for other applications like direct-write lithography, photomask repair, maskless implantation or reverse engineering/restructuring.

  16. Micromachining of semiconductor by femtosecond laser for integrated circuit defect analysis

    International Nuclear Information System (INIS)

    Halbwax, M.; Sarnet, T.; Hermann, J.; Delaporte, Ph.; Sentis, M.; Fares, L.; Haller, G.

    2007-01-01

    The latest International Technology Roadmap for Semiconductors (ITRS) has highlighted the detection and analysis of defects in Integrated Circuits (IC) as a major challenge faced by the semiconductor industry. Advanced tools used today for defect cross sectioning include dual beams (focused ion- and electron-beam technologies) with resolution down to the sub-Angstrom level. However ion milling an IC with a FIB is time consuming because of the need to open wide cavities in front of the cross-sections that need to be analyzed. Therefore the use of a femtosecond laser as a tool for direct material removal is discussed in this paper. Experiments were performed on IC structures to reveal the different layers of fabrication: selective or total ablation can occur depending on the laser energy density, without delamination of the layers. Different laser irradiation conditions like pressure (air, vacuum), polarization, beam shaping, and scanning parameters have been used to produce different types of cavities. The femtosecond laser engraving of silicon-based structures could be useful for cross-sectioning devices but also for other applications like direct-write lithography, photomask repair, maskless implantation or reverse engineering/restructuring

  17. Automatic classification of blank substrate defects

    Science.gov (United States)

    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

  18. Holographic Chern-Simons defects

    International Nuclear Information System (INIS)

    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.

  19. Point defects in solids

    International Nuclear Information System (INIS)

    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

  20. Study of radiation defects by in-situ measurements of the Hall effect in narrow-gap semiconductors

    International Nuclear Information System (INIS)

    Favre, J.

    1990-01-01

    Semiconducting compounds of II-VI, III-V and IV-VI groups were irradiated in liquid hydrogen by high energy (0.7 to 2.7 MeV) electrons. The Hall coefficient and resistivity variations were measured in situ during irradiation. The doping by irradiation induced defects is of p-type in III-V group compounds, while n-type doping occurs in II-VI and IV-VI group materials. A semiconductor to insulator or reverse transition was observed under irradiation when the chemical potential crossed the band edges. In IV-VI group compounds the two successive transitions take place in initially p-type samples. A metastable behaviour, characteristic to strong compensation, appears in the vicinity of those semiconductor - insulator transitions in IV-VI compounds. The slope of free carrier concentration vs. fluence variation was analyzed. It was compared to defect creation rates, calculated in the framework of a cascade model. The charge state of created defects was deduced in this way. - In IV-VI group compounds, the presence of localized levels degenerated with the conduction band and, in PbTe, of additional defect associated levels in the forbidden gap, was demonstrated. Those results are consistent with the saturation of electron concentration increase at high fluence as well as with the analysis of annealing experiments. - In Hg 1-x Cd x Te compounds, the analysis of electron concentration versus fluence increase indicates that only mercury Frenkel pairs are electrically active. The variation with cadmium content of the defect associated level energy was deduced from the saturation values of the electron concentration [fr

  1. Defect detection using transient thermography

    International Nuclear Information System (INIS)

    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)

  2. Thermomchromic Reaction-Induced Reversible Upconversion Emission Modulation for Switching Devices and Tunable Upconversion Emission Based on Defect Engineering of WO3:Yb3+,Er3+ Phosphor.

    Science.gov (United States)

    Ruan, Jiufeng; Yang, Zhengwen; Huang, Anjun; Zhang, Hailu; Qiu, Jianbei; Song, Zhiguo

    2018-05-02

    Reversible luminescence modulation of upconversion phosphors has the potential applications as photoswitches and optical memory and data storage devices. Previously, the photochromic reaction was extensively used for the realization of reversible luminescence modulation. It is very necessary to develop other approaches such as thermomchromic reaction to obtain the reversible upconversion luminescence modulation. In this work, the WO 3 :Yb 3+ ,Er 3+ phosphors with various colors were prepared at various temperatures, exhibiting tunable upconversion luminescence attributed to the formation of oxygen vacancies in the host. Upon heat treatment in the reducing atmosphere or air, the WO 3 :Yb 3+ ,Er 3+ phosphors show a reversible thermomchromic property. The reversible upconversion luminescence modulation of WO 3 :Yb 3+ ,Er 3+ phosphors was observed based on thermomchromic reaction. Additionally, the upconversion luminescence modulation is maintained after several cycles, indicating its excellent stability. The WO 3 :Yb 3+ ,Er 3+ phosphors with reversible upconversion luminescence and excellent reproducibility have potential applications as the photoswitches and optical memory and data storage devices.

  3. Growth hormone receptor gene mutations in two Italian patients with Laron Syndrome.

    Science.gov (United States)

    Fassone, L; Corneli, G; Bellone, S; Camacho-Hübner, C; Aimaretti, G; Cappa, M; Ubertini, G; Bona, G

    2007-05-01

    Laron Syndrome (LS) represents a condition characterized by GH insensitivity caused by molecular defects in the GH receptor (GHR) gene or in the post-receptor signalling pathway. We report the molecular characterization of two unrelated Italian girls from Sicily diagnosed with LS. The DNA sequencing of the GHR gene revealed the presence of different nonsense mutations, occurring in the same background haplotype. The molecular defects occurred in the extracellular domain of the GHR leading to a premature termination signal and to a truncated non-functional receptor. In one patient, a homozygous G to T transversion, in exon 6, led to the mutation GAA to TAA at codon 180 (E180X), while in the second patient a homozygous C to T transition in exon 7 was detected, causing the CGA to TAA substitution at codon 217 (R217X). Both probands presented the polymorphisms Gly168Gly and Ile544Leu in a homozygous state in exons 6 and 10, respectively. The E180X represents a novel defect of the GHR gene, while the R217X mutation has been previously reported in several patients from different ethnic backgrounds but all from countries located in the Mediterranean and Middle Eastern region.

  4. EUV actinic defect inspection and defect printability at the sub-32 nm half pitch

    Energy Technology Data Exchange (ETDEWEB)

    Huh, Sungmin; Kearney, Patrick; Wurm, Stefan; Goodwin, Frank; Han, Hakseung; Goldberg, Kenneth; Mochi, Iacopp; Gullikson, Eric M.

    2009-08-01

    Extreme ultraviolet (EUV) mask blanks with embedded phase defects were inspected with a reticle actinic inspection tool (AIT) and the Lasertec M7360. The Lasertec M7360, operated at SEMA TECH's Mask Blank Development Center (MBDC) in Albany, NY, has a sensitivity to multilayer defects down to 40-45 nm, which is not likely sufficient for mask blank development below the 32 nm half-pitch node. Phase defect printability was simulated to calculate the required defect sensitivity for a next generation blank inspection tool to support reticle development for the sub-32 nm half-pitch technology node. Defect mitigation technology is proposed to take advantage of mask blanks with some defects. This technology will reduce the cost of ownership of EUV mask blanks. This paper will also discuss the kind of infrastructure that will be required for the development and mass production stages.

  5. Reverse genetics with animal viruses. NSV reverse genetics

    International Nuclear Information System (INIS)

    Mebatsion, T.

    2005-01-01

    New strategies to genetically manipulate the genomes of several important animal pathogens have been established in recent years. This article focuses on the reverse genetics techniques, which enables genetic manipulation of the genomes of non-segmented negative-sense RNA viruses. Recovery of a negative-sense RNA virus entirely from cDNA was first achieved for rabies virus in 1994. Since then, reverse genetic systems have been established for several pathogens of medical and veterinary importance. Based on the reverse genetics technique, it is now possible to design safe and more effective live attenuated vaccines against important viral agents. In addition, genetically tagged recombinant viruses can be designed to facilitate serological differentiation of vaccinated animals from infected animals. The approach of delivering protective immunogens of different pathogens using a single vector was made possible with the introduction of the reverse genetics system, and these novel broad-spectrum vaccine vectors have potential applications in improving animal health in developing countries. (author)

  6. Accurate defect die placement and nuisance defect reduction for reticle die-to-die inspections

    Science.gov (United States)

    Wen, Vincent; Huang, L. R.; Lin, C. J.; Tseng, Y. N.; Huang, W. H.; Tuo, Laurent C.; Wylie, Mark; Chen, Ellison; Wang, Elvik; Glasser, Joshua; Kelkar, Amrish; Wu, David

    2015-10-01

    Die-to-die reticle inspections are among the simplest and most sensitive reticle inspections because of the use of an identical-design neighboring-die for the reference image. However, this inspection mode can have two key disadvantages: (1) The location of the defect is indeterminate because it is unclear to the inspector whether the test or reference image is defective; and (2) nuisance and false defects from mask manufacturing noise and tool optical variation can limit the usable sensitivity. The use of a new sequencing approach for a die-to-die inspection can resolve these issues without any additional scan time, without sacrifice in sensitivity requirement, and with a manageable increase in computation load. In this paper we explore another approach for die-to-die inspections using a new method of defect processing and sequencing. Utilizing die-to-die double arbitration during defect detection has been proven through extensive testing to generate accurate placement of the defect in the correct die to ensure efficient defect disposition at the AIMS step. The use of this method maintained the required inspection sensitivity for mask quality as verified with programmed-defectmask qualification and then further validated with production masks comparing the current inspection approach to the new method. Furthermore, this approach can significantly reduce the total number of defects that need to be reviewed by essentially eliminating the nuisance and false defects that can result from a die-to-die inspection. This "double-win" will significantly reduce the effort in classifying a die-to-die inspection result and will lead to improved cycle times.

  7. Multiscale crystal defect dynamics: A coarse-grained lattice defect model based on crystal microstructure

    Science.gov (United States)

    Lyu, Dandan; Li, Shaofan

    2017-10-01

    Crystal defects have microstructure, and this microstructure should be related to the microstructure of the original crystal. Hence each type of crystals may have similar defects due to the same failure mechanism originated from the same microstructure, if they are under the same loading conditions. In this work, we propose a multiscale crystal defect dynamics (MCDD) model that models defects by considering its intrinsic microstructure derived from the microstructure or material genome of the original perfect crystal. The main novelties of present work are: (1) the discrete exterior calculus and algebraic topology theory are used to construct a scale-up (coarse-grained) dual lattice model for crystal defects, which may represent all possible defect modes inside a crystal; (2) a higher order Cauchy-Born rule (up to the fourth order) is adopted to construct atomistic-informed constitutive relations for various defect process zones, and (3) an hierarchical strain gradient theory based finite element formulation is developed to support an hierarchical multiscale cohesive (process) zone model for various defects in a unified formulation. The efficiency of MCDD computational algorithm allows us to simulate dynamic defect evolution at large scale while taking into account atomistic interaction. The MCDD model has been validated by comparing of the results of MCDD simulations with that of molecular dynamics (MD) in the cases of nanoindentation and uniaxial tension. Numerical simulations have shown that MCDD model can predict dislocation nucleation induced instability and inelastic deformation, and thus it may provide an alternative solution to study crystal plasticity.

  8. Surface defects and chiral algebras

    Energy Technology Data Exchange (ETDEWEB)

    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.

  9. Laterality defects in the national birth defects prevention study 1998-2007 birth prevalence and descriptive epidemiology

    Science.gov (United States)

    Little is known epidemiologically about laterality defects. Using data from the National Birth Defects Prevention Study (NBDPS), a large multi-site case-control study of birth defects, we analyzed prevalence and selected characteristics in children born with laterality defects born from 1998 to 2007...

  10. Defects at oxide surfaces

    CERN Document Server

    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...

  11. 48 CFR 1615.407-1 - Rate reduction for defective pricing or defective cost or pricing data.

    Science.gov (United States)

    2010-10-01

    ... defective pricing or defective cost or pricing data. 1615.407-1 Section 1615.407-1 Federal Acquisition... CONTRACTING METHODS AND CONTRACT TYPES CONTRACTING BY NEGOTIATION Contract Pricing 1615.407-1 Rate reduction for defective pricing or defective cost or pricing data. The clause set forth in section 1652.215-70...

  12. 48 CFR 1652.215-70 - Rate Reduction for Defective Pricing or Defective Cost or Pricing Data.

    Science.gov (United States)

    2010-10-01

    ... Defective Pricing or Defective Cost or Pricing Data. 1652.215-70 Section 1652.215-70 Federal Acquisition... CLAUSES AND FORMS CONTRACT CLAUSES Texts of FEHBP Clauses 1652.215-70 Rate Reduction for Defective Pricing or Defective Cost or Pricing Data. As prescribed in 1615.407-1, the following clause shall be...

  13. Point defects in platinum

    International Nuclear Information System (INIS)

    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)

  14. Defect-rich TiO2-δ nanocrystals confined in a mooncake-shaped porous carbon matrix as an advanced Na ion battery anode

    Science.gov (United States)

    He, Hanna; Zhang, Qi; Wang, Haiyan; Zhang, Hehe; Li, Jiadong; Peng, Zhiguang; Tang, Yougen; Shao, Minhua

    2017-06-01

    Inferior electronic conductivity and sluggish sodium ion diffusion are still two big challenges for TiO2 anode material for Na ion batteries (SIBs). Herein, we synthesize TiO2/C composites by the pyrolysis of MIL-125(Ti) precursor and successfully introduce defects to TiO2/C composite by a simple magnesium reduction. The as-prepared defect-rich TiO2-δ/C composite shows mooncake-shaped morphology consisting of TiO2-δ nanocrystals with an average particle size of 5 nm well dispersed in the carbon matrix. When used as a SIBs anode, the defect-rich TiO2-δ/C composite exhibits a high reversible capacity of 330.2 mAh g-1 at 50 mA g-1 at the voltage range of 0.001-3.0 V and long-term cycling stability with negligible decay after 5000 cycles. Compared with other four TiO2/C samples, the electrochemical performance of defect-rich TiO2-δ/C is highly improved, which may benefit from the enhanced electronic/ionic conductivities owing to the defect-rich features, high surface area rendering shortened electronic and ionic diffusion path, and the suppress of the TiO2 crystal aggregation during sodiation and desodiation process by the carbon matrix.

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

    International Nuclear Information System (INIS)

    Vanhellemont, J.; Romano-Rodriguez, A.

    1994-01-01

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

  16. Casein Kinase 2 Reverses Tail-Independent Inactivation of Kinesin-1

    Science.gov (United States)

    Xu, Jing

    2013-03-01

    Kinesin-1 is a plus-end microtubule-based motor, and defects in kinesin-based transport are linked to diseases including neurodegeneration. Kinesin can auto-inhibit via a head-tail interaction, but is believed to be active otherwise. Here we report a tail-independent inactivation of kinesin, reversible by the disease-relevant signalling protein, casein kinase 2 (CK2). The majority of initially active kinesin (native or tail-less) loses its ability to interact with microtubules in vitro, and CK2 reverses this inactivation (approximately fourfold) without altering kinesin's single motor properties. This activation pathway does not require motor phosphorylation, and is independent of head-tail auto-inhibition. In cultured mammalian cells, reducing CK2 expression, but not its kinase activity, decreases the force required to stall lipid droplet transport, consistent with a decreased number of active kinesin motors. Our results (Nat. Commun., 3:754, 2012) provide the first direct evidence of a protein kinase upregulating kinesin-based transport, and suggest a novel pathway for regulating the activity of cargo-bound kinesin. Work supported by NIGMS grants GM64624 to SPG, GM74830-06A1 to LH, GM76516 to LB, NS048501 to SJK, and AHA grant 825278F to JX.

  17. EPR reversible signature of self-trapped holes in fictive temperature-treated silica glass

    Science.gov (United States)

    Lancry, Matthieu; Ollier, Nadège; Babu, B. H.; Herrero, Christian; Poumellec, Bertrand

    2018-03-01

    Post-mortem electron paramagnetic resonance spectroscopy experiments have been carried out between room temperature and 20 K to examine the radiation-induced defects in fictive temperature (Tf) treated Heraeus F300 silica (0.1 ppm OH, 1500 ppm Cl2). In particular, we focus our attention on Self-Trapped Hole (STH) centers detected in 1000 °C, 1100 °C, and 1200 °C Tf treated samples irradiated at room temperature by gamma rays at 6 kGy. By repeating annealing cycles between 77 and 300 K on the same samples, we observed that the EPR signal attributed to STH decreases as the temperature increases but in a reversible manner. We evidenced a deviation from the Curie law for T > 70 K and suggested an interpretation based on the decrease in the "strain-assisted TH" population by reversible excitation of the trapped hole to a delocalized state with an activation energy of 7.8 meV. This also means that the precursors of hole trapping sites (a local strain atomic configuration) remain stable until 300 K at least.

  18. Congenital Heart Defects and CCHD

    Science.gov (United States)

    ... 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 ...

  19. Neutron diffraction and lattice defects

    International Nuclear Information System (INIS)

    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.)

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

    Science.gov (United States)

    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

  1. Computer simulation of defect cluster

    Energy Technology Data Exchange (ETDEWEB)

    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.)

  2. Norwegian Pitched Roof Defects

    Directory of Open Access Journals (Sweden)

    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.

  3. Congenital platelet function defects

    Science.gov (United States)

    ... 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 ...

  4. Metallography of defects

    International Nuclear Information System (INIS)

    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

  5. A coverage and slicing dependencies analysis for seeking software security defects.

    Science.gov (United States)

    He, Hui; Zhang, Dongyan; Liu, Min; Zhang, Weizhe; Gao, Dongmin

    2014-01-01

    Software security defects have a serious impact on the software quality and reliability. It is a major hidden danger for the operation of a system that a software system has some security flaws. When the scale of the software increases, its vulnerability has becoming much more difficult to find out. Once these vulnerabilities are exploited, it may lead to great loss. In this situation, the concept of Software Assurance is carried out by some experts. And the automated fault localization technique is a part of the research of Software Assurance. Currently, automated fault localization method includes coverage based fault localization (CBFL) and program slicing. Both of the methods have their own location advantages and defects. In this paper, we have put forward a new method, named Reverse Data Dependence Analysis Model, which integrates the two methods by analyzing the program structure. On this basis, we finally proposed a new automated fault localization method. This method not only is automation lossless but also changes the basic location unit into single sentence, which makes the location effect more accurate. Through several experiments, we proved that our method is more effective. Furthermore, we analyzed the effectiveness among these existing methods and different faults.

  6. An algebra of reversible computation.

    Science.gov (United States)

    Wang, Yong

    2016-01-01

    We design an axiomatization for reversible computation called reversible ACP (RACP). It has four extendible modules: basic reversible processes algebra, algebra of reversible communicating processes, recursion and abstraction. Just like process algebra ACP in classical computing, RACP can be treated as an axiomatization foundation for reversible computation.

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

    Science.gov (United States)

    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.

  8. On thermodynamic and microscopic reversibility

    International Nuclear Information System (INIS)

    Crooks, Gavin E

    2011-01-01

    The word 'reversible' has two (apparently) distinct applications in statistical thermodynamics. A thermodynamically reversible process indicates an experimental protocol for which the entropy change is zero, whereas the principle of microscopic reversibility asserts that the probability of any trajectory of a system through phase space equals that of the time reversed trajectory. However, these two terms are actually synonymous: a thermodynamically reversible process is microscopically reversible, and vice versa

  9. Comparative skeletal features between Homo floresiensis and patients with primary growth hormone insensitivity (Laron Syndrome).

    Science.gov (United States)

    Hershkovitz, Israel; Kornreich, Liora; Laron, Zvi

    2007-10-01

    Comparison between the skeletal remains of Homo floresiensis and the auxological and roentgenological findings in a large Israeli cohort of patients with Laron Syndrome (LS, primary or classical GH insensitivity or resistance) revealed striking morphological similarities, including extremely small stature and reduced cranial volume. LS is an autosomal recessive disease caused by a molecular defect of the Growth Hormone (GH) receptor or in the post-receptor cascades. Epidemiological studies have shown that LS occurs more often in consanguineous families and isolates, and it has been described in several countries in South East Asia. It is our conclusion that the findings from the island of Flores, which were attributed to a new species of the genus Homo, may in fact represent a local, highly inbred, Homo sapiens population in whom a mutation for the GH receptor had occurred. (c) 2007 Wiley-Liss, Inc.

  10. Implications of defect clusters formed in cascades on free defect generation and microstructural development

    International Nuclear Information System (INIS)

    Wiedersich, H.

    1992-12-01

    A large fraction of the defects produced by irradiation with energetic neutrons or heavy ions originates in cascades. Not only increased recombination of vacancy and interstitial defects but also significant clustering of like defects occur. Both processes reduce the number of point defects available for long range migration. Consequences of defect clustering in cascades will be discussed in a semi-quantitative form with the aid of calculations using a very simplified model: Quasi-steady-state distributions of immobile vacancy and/or interstitial clusters develop which, in turn, can become significant sinks for mobile defects, and, therefore reduce their lifetime. Although cluster sinks will cause segregation and, potentially, precipitation of second phases due to local changes of composition, the finite lifetime of clusters will not lead to lasting, local compositional changes. A transition from highly dense interstitial and vacancy cluster distributions to the void swelling regime occurs when the thermal evaporation of vacancies from small vacancy clusters becomes significant at higher temperatures. Unequal clustering of vacancies and interstitials leads to an imbalance of their fluxes of in the matrix and, hence, to unequal contributions to atom transport by interstitials and by vacancies even in the quasi-steady state approximation

  11. Characterization of point defects in monolayer arsenene

    Science.gov (United States)

    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.

  12. Beating Birth Defects

    Centers for Disease Control (CDC) Podcasts

    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.

  13. Reversibility of female sterilization.

    Science.gov (United States)

    Siegler, A M; Hulka, J; Peretz, A

    1985-04-01

    The discussion considers the current status of reversibility of sterilization in the US and describes clinical and experimental efforts for developing techniques designed for reversibility. It focuses on regret following sterilization, reversal potential of current sterilization techniques, patient selection, current reversal techniques, results of sterilization procedures, experimental approaches to reversal of current techniques of sterilization, and sterilization procedures devised for reversibility, in humans and in animals. Request is the 1st stage of reversal, but a request for sterilization reversal (SR) does not always mean regret for a decision made at the time. Frequently it is a wish to restore fertility because life circumstances have changed after a sterilization that was ppropriate at the time it was performed. Schwyhart and Kutner reviewed 22 studies published between 1949-69 in which they found that the percentage of patients regretting the procedure ranged from 1.3-15%. Requests for reversal remain low in most countries, but if sterilization becomes a more popular method of contraception, requests will also increase. The ideal operation considered as a reversaible method of sterilization should include an easy, reliable outpatient method of tubal occlusion with miniml risk or patient discomfort that subsequently could be reversed without the need for a major surgical intervention. Endoscopic methods have progressed toward the 1st objective. A recent search of the literature uncovered few series of SR of more than 50 cases. The 767 operations found were analyzed with regard to pregnancy outcome. The precent of live births varied from 74-78.8%, and the occurance of tubal pregnancies ranged from 1.7-6.5%. All of the confounding variables in patient selection and small numbers of reported procedures preclude any conclusion about the different techniques or the number of operations that give a surgeon a level of expertise. Few authors classify their

  14. Toward Intelligent Software Defect Detection

    Science.gov (United States)

    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.

  15. Thyroid Medication Use and Birth Defects in the National Birth Defects Prevention Study.

    Science.gov (United States)

    Howley, Meredith M; Fisher, Sarah C; Van Zutphen, Alissa R; Waller, Dorothy K; Carmichael, Suzan L; Browne, Marilyn L

    2017-11-01

    Thyroid disorders are common among reproductive-aged women, with hypothyroidism affecting 2 to 3% of pregnancies, and hyperthyroidism affecting an additional 0.1 to 1%. We examined associations between thyroid medications and individual birth defects using data from the National Birth Defects Prevention Study (NBDPS). The NBDPS is a multisite, population-based, case-control study that included pregnancies with estimated delivery dates from 1997 to 2011. We analyzed self-reported thyroid medication use from mothers of 31,409 birth defect cases and 11,536 unaffected controls. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression for birth defects with five or more exposed cases, controlling for maternal age, race/ethnicity, and study center. Crude ORs and exact 95% CIs were estimated for defects with 3 to 4 exposed cases. Thyroid hormone was used by 738 (2.3%) case and 237 (2.1%) control mothers, and was associated with anencephaly (OR = 1.68; 95% CI, 1.03-2.73), holoprosencephaly (OR = 2.48; 95% CI, 1.13-5.44), hydrocephaly (1.77; 95% CI, 1.07-2.95) and small intestinal atresia (OR = 1.81; 95% CI, 1.04-3.15). Anti-thyroid medication was used by 34 (0.1%) case and 10 (<0.1%) control mothers, and was associated with aortic valve stenosis (OR = 6.91; 95% CI, 1.21-27.0). While new associations were identified, our findings are relatively consistent with previous NBDPS analyses. Our findings suggest thyroid medication use is not associated with most birth defects studied in the NBDPS, but may be associated with some specific birth defects. These results should not be interpreted to suggest that medications used to treat thyroid disease are teratogens, as the observed associations may reflect effects of the underlying thyroid disease. Birth Defects Research 109:1471-1481, 2017.© 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  16. Laser ultrasound and simulated time reversal on bulk waves for non destructive control

    International Nuclear Information System (INIS)

    Diot, G; Walaszek, H; Kouadri-David, A; Guégan, S; Flifla, J

    2014-01-01

    Laser welding of aluminium generally creates embedded welding defects, such as porosities or cracks. Non Destructive Inspection (NDI) after processing may ensure an acceptable weld quality by defect detection. Nowadays, NDI techniques used to control the inside of a weld are mainly limited to X-Rays or ultrasonics. The current paper describes the use of a Laser Ultrasound (LU) technique to inspect porosities in 2 and 4-mm thick sheet lap welds. First experimentations resulted in the detection of 0.5-mm drilled holes in bulk aluminium sheets. The measurement of the depth of these defects is demonstrated too. Further experimentations shows the applicability of the LU technique to detect porosities in aluminium laser welds. However, as the interpretation of raw measures is limiting the detection capacity of this technique, we developed a signal processing using Time-Reversal capabilities to enhance detection capacities. Furthermore, the signal processing output is a geometrical image of the material's inner state, increasing the ease of interpretation. It is based on a mass-spring simulation which enables the back-propagation of the acquired ultrasound signal. The spring-mass simulation allows the natural generation of all the different sound waves and thus enables the back-propagation of a raw signal without any need of filtering or wave identification and extraction. Therefore the signal processing uses the information contained in the compression wave as well as in the shear wave

  17. Constraining the reversing and non-reversing modes of the geodynamo. New insights from magnetostratigraphy.

    Science.gov (United States)

    Gallet, Y.; Pavlov, V.; Shatsillo, A.; Hulot, G.

    2015-12-01

    Constraining the evolution in the geomagnetic reversal frequency over hundreds of million years is not a trivial matter. Beyond the fact that there are long periods without reversals, known as superchrons, and periods with many reversals, the way the reversal frequency changes through time during reversing periods is still debated. A smooth evolution or a succession of stationary segments have both been suggested to account for the geomagnetic polarity time scale since the Middle-Late Jurassic. Sudden changes from a reversing mode to a non-reversing mode of the geodynamo may also well have happened, the switch between the two modes having then possibly been controlled by the thermal conditions at the core-mantle boundary. There is, nevertheless, a growing set of magnetostratigraphic data, which could help decipher a proper interpretation of the reversal history, in particular in the early Paleozoic and even during the Precambrian. Although yielding a fragmentary record, these data reveal the occurrence of both additional superchrons and periods characterized by extremely high, not to say extraordinary, magnetic reversal frequencies. In this talk, we will present a synthesis of these data, mainly obtained from Siberia, and discuss their implication for the magnetic reversal behavior over the past billion years.

  18. Embedded defects

    International Nuclear Information System (INIS)

    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

  19. Study of residue type defect formation mechanism and the effect of advanced defect reduction (ADR) rinse process

    Science.gov (United States)

    Arima, Hiroshi; Yoshida, Yuichi; Yoshihara, Kosuke; Shibata, Tsuyoshi; Kushida, Yuki; Nakagawa, Hiroki; Nishimura, Yukio; Yamaguchi, Yoshikazu

    2009-03-01

    Residue type defect is one of yield detractors in lithography process. It is known that occurrence of the residue type defect is dependent on resist development process and the defect is reduced by optimized rinsing condition. However, the defect formation is affected by resist materials and substrate conditions. Therefore, it is necessary to optimize the development process condition by each mask level. Those optimization steps require a large amount of time and effort. The formation mechanism is investigated from viewpoint of both material and process. The defect formation is affected by resist material types, substrate condition and development process condition (D.I.W. rinse step). Optimized resist formulation and new rinse technology significantly reduce the residue type defect.

  20. Strained interface defects in silicon nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    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)

  1. Craniotomy Frontal Bone Defect

    African Journals Online (AJOL)

    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 ...

  2. Who named the quantum defect?

    International Nuclear Information System (INIS)

    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

  3. Designing a Multistage Supply Chain in Cross-Stage Reverse Logistics Environments: Application of Particle Swarm Optimization Algorithms

    Directory of Open Access Journals (Sweden)

    Tzu-An Chiang

    2014-01-01

    Full Text Available This study designed a cross-stage reverse logistics course for defective products so that damaged products generated in downstream partners can be directly returned to upstream partners throughout the stages of a supply chain for rework and maintenance. To solve this reverse supply chain design problem, an optimal cross-stage reverse logistics mathematical model was developed. In addition, we developed a genetic algorithm (GA and three particle swarm optimization (PSO algorithms: the inertia weight method (PSOA_IWM, VMax method (PSOA_VMM, and constriction factor method (PSOA_CFM, which we employed to find solutions to support this mathematical model. Finally, a real case and five simulative cases with different scopes were used to compare the execution times, convergence times, and objective function values of the four algorithms used to validate the model proposed in this study. Regarding system execution time, the GA consumed more time than the other three PSOs did. Regarding objective function value, the GA, PSOA_IWM, and PSOA_CFM could obtain a lower convergence value than PSOA_VMM could. Finally, PSOA_IWM demonstrated a faster convergence speed than PSOA_VMM, PSOA_CFM, and the GA did.

  4. Designing a multistage supply chain in cross-stage reverse logistics environments: application of particle swarm optimization algorithms.

    Science.gov (United States)

    Chiang, Tzu-An; Che, Z H; Cui, Zhihua

    2014-01-01

    This study designed a cross-stage reverse logistics course for defective products so that damaged products generated in downstream partners can be directly returned to upstream partners throughout the stages of a supply chain for rework and maintenance. To solve this reverse supply chain design problem, an optimal cross-stage reverse logistics mathematical model was developed. In addition, we developed a genetic algorithm (GA) and three particle swarm optimization (PSO) algorithms: the inertia weight method (PSOA_IWM), V(Max) method (PSOA_VMM), and constriction factor method (PSOA_CFM), which we employed to find solutions to support this mathematical model. Finally, a real case and five simulative cases with different scopes were used to compare the execution times, convergence times, and objective function values of the four algorithms used to validate the model proposed in this study. Regarding system execution time, the GA consumed more time than the other three PSOs did. Regarding objective function value, the GA, PSOA_IWM, and PSOA_CFM could obtain a lower convergence value than PSOA_VMM could. Finally, PSOA_IWM demonstrated a faster convergence speed than PSOA_VMM, PSOA_CFM, and the GA did.

  5. Designing a Multistage Supply Chain in Cross-Stage Reverse Logistics Environments: Application of Particle Swarm Optimization Algorithms

    Science.gov (United States)

    Chiang, Tzu-An; Che, Z. H.

    2014-01-01

    This study designed a cross-stage reverse logistics course for defective products so that damaged products generated in downstream partners can be directly returned to upstream partners throughout the stages of a supply chain for rework and maintenance. To solve this reverse supply chain design problem, an optimal cross-stage reverse logistics mathematical model was developed. In addition, we developed a genetic algorithm (GA) and three particle swarm optimization (PSO) algorithms: the inertia weight method (PSOA_IWM), V Max method (PSOA_VMM), and constriction factor method (PSOA_CFM), which we employed to find solutions to support this mathematical model. Finally, a real case and five simulative cases with different scopes were used to compare the execution times, convergence times, and objective function values of the four algorithms used to validate the model proposed in this study. Regarding system execution time, the GA consumed more time than the other three PSOs did. Regarding objective function value, the GA, PSOA_IWM, and PSOA_CFM could obtain a lower convergence value than PSOA_VMM could. Finally, PSOA_IWM demonstrated a faster convergence speed than PSOA_VMM, PSOA_CFM, and the GA did. PMID:24772026

  6. Serine biosynthesis and transport defects.

    Science.gov (United States)

    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.

  7. Reversibility of neuropathology in Tay-Sachs-related diseases.

    Science.gov (United States)

    Cachón-González, María-Begoña; Wang, Susan Z; Ziegler, Robin; Cheng, Seng H; Cox, Timothy M

    2014-02-01

    The GM2 gangliosidoses are progressive neurodegenerative disorders due to defects in the lysosomal β-N-acetylhexosaminidase system. Accumulation of β-hexosaminidases A and B substrates is presumed to cause this fatal condition. An authentic mouse model of Sandhoff disease (SD) with pathological characteristics resembling those noted in infantile GM2 gangliosidosis has been described. We have shown that expression of β-hexosaminidase by intracranial delivery of recombinant adeno-associated viral vectors to young adult SD mice can prevent many features of the disease and extends lifespan. To investigate the nature of the neurological injury in GM2 gangliosidosis and the extent of its reversibility, we have examined the evolution of disease in the SD mouse; we have moreover explored the effects of gene transfer delivered at key times during the course of the illness. Here we report greatly increased survival only when the therapeutic genes are expressed either before the disease is apparent or during its early manifestations. However, irrespective of when treatment was administered, widespread and abundant expression of β-hexosaminidase with consequent clearance of glycoconjugates, α-synuclein and ubiquitinated proteins, and abrogation of inflammatory responses and neuronal loss was observed. We also show that defects in myelination occur in early life and cannot be easily resolved when treatment is given to the adult brain. These results indicate that there is a limited temporal opportunity in which function and survival can be improved-but regardless of resolution of the cardinal pathological features of GM2 gangliosidosis, a point is reached when functional deterioration and death cannot be prevented.

  8. Reversible skeletal abnormalities in gamma-glutamyl transpeptidase-deficient mice

    Science.gov (United States)

    Levasseur, Regis; Barrios, Roberto; Elefteriou, Florent; Glass, Donald A 2nd; Lieberman, Michael W.; Karsenty, Gerard

    2003-01-01

    Gamma-glutamyl transpeptidase (GGT) is a widely distributed ectopeptidase responsible for the degradation of glutathione in the gamma-glutamyl cycle. This cycle is implicated in the metabolism of cysteine, and absence of GGT causes a severe intracellular decrease in this amino acid. GGT-deficient (GGT-/-) mice have multiple metabolic abnormalities and are dwarf. We show here that this latter phenotype is due to a decreased of the growth plate cartilage total height resulting from a proliferative defect of chondrocytes. In addition, analysis of vertebrae and tibiae of GGT-/- mice revealed a severe osteopenia. Histomorphometric studies showed that this low bone mass phenotype results from an increased osteoclast number and activity as well as from a marked decrease in osteoblast activity. Interestingly, neither osteoblasts, osteoclasts, nor chondrocytes express GGT, suggesting that the observed defects are secondary to other abnormalities. N-acetylcysteine supplementation has been shown to reverse the metabolic abnormalities of the GGT-/- mice and in particular to restore the level of IGF-1 and sex steroids in these mice. Consistent with these previous observations, N-acetylcysteine treatment of GGT-/- mice ameliorates their skeletal abnormalities by normalizing chondrocytes proliferation and osteoblastic function. In contrast, resorbtion parameters are only partially normalized in GGT-/- N-acetylcysteine-treated mice, suggesting that GGT regulates osteoclast biology at least partly independently of these hormones. These results establish the importance of cysteine metabolism for the regulation of bone remodeling and longitudinal growth.

  9. Analytical reverse time migration: An innovation in imaging of infrastructures using ultrasonic shear waves.

    Science.gov (United States)

    Asadollahi, Aziz; Khazanovich, Lev

    2018-04-11

    The emergence of ultrasonic dry point contact (DPC) transducers that emit horizontal shear waves has enabled efficient collection of high-quality data in the context of a nondestructive evaluation of concrete structures. This offers an opportunity to improve the quality of evaluation by adapting advanced imaging techniques. Reverse time migration (RTM) is a simulation-based reconstruction technique that offers advantages over conventional methods, such as the synthetic aperture focusing technique. RTM is capable of imaging boundaries and interfaces with steep slopes and the bottom boundaries of inclusions and defects. However, this imaging technique requires a massive amount of memory and its computation cost is high. In this study, both bottlenecks of the RTM are resolved when shear transducers are used for data acquisition. An analytical approach was developed to obtain the source and receiver wavefields needed for imaging using reverse time migration. It is shown that the proposed analytical approach not only eliminates the high memory demand, but also drastically reduces the computation time from days to minutes. Copyright © 2018 Elsevier B.V. All rights reserved.

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

    International Nuclear Information System (INIS)

    Gislason, H.P.

    1989-01-01

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

  11. Paternal occupation and birth defects: findings from the National Birth Defects Prevention Study.

    NARCIS (Netherlands)

    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

  12. [Inconformity between soft tissue defect and bony defect in incomplete cleft palate].

    Science.gov (United States)

    Zhou, Xia; Ma, Lian

    2014-12-01

    To evaluate the inconformity between soft tissue defect and bony defect by observing the cleft extent of palate with complete secondary palate bony cleft in incomplete cleft palate patient. The patients with incomplete cleft palate treated in Hospital of Stomatology Peking University from July 2012 to June 2013 were reviewed, of which 75 cases with complete secondary palate bony cleft were selected in this study. The CT scan and intraoral photograph were taken before operation. The patients were classified as four types according to the extent of soft tissue defect. Type 1: soft tissue defect reached incisive foremen region, Type 2 was hard and soft cleft palate, Type 3 soft cleft palate and Type 4 submucous cleft palate. Type 1 was defined as conformity group (CG). The other three types were defined as inconformity group (ICG) and divided into three subgroups (ICG-I), (ICG-II) and (ICG-III). Fifty-seven patients were in ICG group, and the rate of inconformity was 76% (57/75). The percentage of ICG-I, ICG-II and ICG-III was 47% (27/57), 23% (13/57) and 30% (17/57), respevtively. There are different types of soft tissue deformity with complete secondary palate bony cleft. The inconformity between soft tissue and hard tissue defect exits in 3/4 of isolated cleft palate patients.

  13. Chemical characterisation of non-defective and defective green arabica and robusta coffees by electrospray ionization-mass spectrometry (ESI-MS).

    Science.gov (United States)

    Mendonça, Juliana C F; Franca, Adriana S; Oliveira, Leandro S; Nunes, Marcella

    2008-11-15

    The coffee roasted in Brazil is considered to be of low quality, due to the presence of defective coffee beans that depreciate the beverage quality. These beans, although being separated from the non-defective ones prior to roasting, are still commercialized in the coffee trading market. Thus, it was the aim of this work to verify the feasibility of employing ESI-MS to identify chemical characteristics that will allow the discrimination of Arabica and Robusta species and also of defective and non-defective coffees. Aqueous extracts of green (raw) defective and non-defective coffee beans were analyzed by direct infusion electrospray ionization mass spectrometry (ESI-MS) and this technique provided characteristic fingerprinting mass spectra that not only allowed for discrimination of species but also between defective and non-defective coffee beans. ESI-MS profiles in the positive mode (ESI(+)-MS) provided separation between defective and non-defective coffees within a given species, whereas ESI-MS profiles in the negative mode (ESI(-)-MS) provided separation between Arabica and Robusta coffees. Copyright © 2008 Elsevier Ltd. All rights reserved.

  14. Topological defects from the multiverse

    Science.gov (United States)

    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.

  15. Topological defects from the multiverse

    Energy Technology Data Exchange (ETDEWEB)

    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.

  16. Topological defects from the multiverse

    International Nuclear Information System (INIS)

    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

  17. Biochemical adaptations of mammalian hibernation: exploring squirrels as a perspective model for naturally induced reversible insulin resistance

    Energy Technology Data Exchange (ETDEWEB)

    Wu, C-W.; Biggar, K.K.; Storey, K.B. [Carleton University, Department of Biology, Institute of Biochemistry, Ottawa, ON (Canada)

    2013-01-28

    An important disease among human metabolic disorders is type 2 diabetes mellitus. This disorder involves multiple physiological defects that result from high blood glucose content and eventually lead to the onset of insulin resistance. The combination of insulin resistance, increased glucose production, and decreased insulin secretion creates a diabetic metabolic environment that leads to a lifetime of management. Appropriate models are critical for the success of research. As such, a unique model providing insight into the mechanisms of reversible insulin resistance is mammalian hibernation. Hibernators, such as ground squirrels and bats, are excellent examples of animals exhibiting reversible insulin resistance, for which a rapid increase in body weight is required prior to entry into dormancy. Hibernator studies have shown differential regulation of specific molecular pathways involved in reversible resistance to insulin. The present review focuses on this growing area of research and the molecular mechanisms that regulate glucose homeostasis, and explores the roles of the Akt signaling pathway during hibernation. Here, we propose a link between hibernation, a well-documented response to periods of environmental stress, and reversible insulin resistance, potentially facilitated by key alterations in the Akt signaling network, PPAR-γ/PGC-1α regulation, and non-coding RNA expression. Coincidentally, many of the same pathways are frequently found to be dysregulated during insulin resistance in human type 2 diabetes. Hence, the molecular networks that may regulate reversible insulin resistance in hibernating mammals represent a novel approach by providing insight into medical treatment of insulin resistance in humans.

  18. Biochemical adaptations of mammalian hibernation: exploring squirrels as a perspective model for naturally induced reversible insulin resistance

    International Nuclear Information System (INIS)

    Wu, C-W.; Biggar, K.K.; Storey, K.B.

    2013-01-01

    An important disease among human metabolic disorders is type 2 diabetes mellitus. This disorder involves multiple physiological defects that result from high blood glucose content and eventually lead to the onset of insulin resistance. The combination of insulin resistance, increased glucose production, and decreased insulin secretion creates a diabetic metabolic environment that leads to a lifetime of management. Appropriate models are critical for the success of research. As such, a unique model providing insight into the mechanisms of reversible insulin resistance is mammalian hibernation. Hibernators, such as ground squirrels and bats, are excellent examples of animals exhibiting reversible insulin resistance, for which a rapid increase in body weight is required prior to entry into dormancy. Hibernator studies have shown differential regulation of specific molecular pathways involved in reversible resistance to insulin. The present review focuses on this growing area of research and the molecular mechanisms that regulate glucose homeostasis, and explores the roles of the Akt signaling pathway during hibernation. Here, we propose a link between hibernation, a well-documented response to periods of environmental stress, and reversible insulin resistance, potentially facilitated by key alterations in the Akt signaling network, PPAR-γ/PGC-1α regulation, and non-coding RNA expression. Coincidentally, many of the same pathways are frequently found to be dysregulated during insulin resistance in human type 2 diabetes. Hence, the molecular networks that may regulate reversible insulin resistance in hibernating mammals represent a novel approach by providing insight into medical treatment of insulin resistance in humans

  19. Metastable gravity on classical defects

    International Nuclear Information System (INIS)

    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

  20. Simulation based mask defect repair verification and disposition

    Science.gov (United States)

    Guo, Eric; Zhao, Shirley; Zhang, Skin; Qian, Sandy; Cheng, Guojie; Vikram, Abhishek; Li, Ling; Chen, Ye; Hsiang, Chingyun; Zhang, Gary; Su, Bo

    2009-10-01

    As the industry moves towards sub-65nm technology nodes, the mask inspection, with increased sensitivity and shrinking critical defect size, catches more and more nuisance and false defects. Increased defect counts pose great challenges in the post inspection defect classification and disposition: which defect is real defect, and among the real defects, which defect should be repaired and how to verify the post-repair defects. In this paper, we address the challenges in mask defect verification and disposition, in particular, in post repair defect verification by an efficient methodology, using SEM mask defect images, and optical inspection mask defects images (only for verification of phase and transmission related defects). We will demonstrate the flow using programmed mask defects in sub-65nm technology node design. In total 20 types of defects were designed including defects found in typical real circuit environments with 30 different sizes designed for each type. The SEM image was taken for each programmed defect after the test mask was made. Selected defects were repaired and SEM images from the test mask were taken again. Wafers were printed with the test mask before and after repair as defect printability references. A software tool SMDD-Simulation based Mask Defect Disposition-has been used in this study. The software is used to extract edges from the mask SEM images and convert them into polygons to save in GDSII format. Then, the converted polygons from the SEM images were filled with the correct tone to form mask patterns and were merged back into the original GDSII design file. This merge is for the purpose of contour simulation-since normally the SEM images cover only small area (~1 μm) and accurate simulation requires including larger area of optical proximity effect. With lithography process model, the resist contour of area of interest (AOI-the area surrounding a mask defect) can be simulated. If such complicated model is not available, a simple

  1. Defects in new protective aprons

    International Nuclear Information System (INIS)

    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

  2. Electric-Field-Driven Dual Vacancies Evolution in Ultrathin Nanosheets Realizing Reversible Semiconductor to Half-Metal Transition.

    Science.gov (United States)

    Lyu, Mengjie; Liu, Youwen; Zhi, Yuduo; Xiao, Chong; Gu, Bingchuan; Hua, Xuemin; Fan, Shaojuan; Lin, Yue; Bai, Wei; Tong, Wei; Zou, Youming; Pan, Bicai; Ye, Bangjiao; Xie, Yi

    2015-12-02

    Fabricating a flexible room-temperature ferromagnetic resistive-switching random access memory (RRAM) device is of fundamental importance to integrate nonvolatile memory and spintronics both in theory and practice for modern information technology and has the potential to bring about revolutionary new foldable information-storage devices. Here, we show that a relatively low operating voltage (+1.4 V/-1.5 V, the corresponding electric field is around 20,000 V/cm) drives the dual vacancies evolution in ultrathin SnO2 nanosheets at room temperature, which causes the reversible transition between semiconductor and half-metal, accompanyied by an abrupt conductivity change up to 10(3) times, exhibiting room-temperature ferromagnetism in two resistance states. Positron annihilation spectroscopy and electron spin resonance results show that the Sn/O dual vacancies in the ultrathin SnO2 nanosheets evolve to isolated Sn vacancy under electric field, accounting for the switching behavior of SnO2 ultrathin nanosheets; on the other hand, the different defect types correspond to different conduction natures, realizing the transition between semiconductor and half-metal. Our result represents a crucial step to create new a information-storage device realizing the reversible transition between semiconductor and half-metal with flexibility and room-temperature ferromagnetism at low energy consumption. The as-obtained half-metal in the low-resistance state broadens the application of the device in spintronics and the semiconductor to half-metal transition on the basis of defects evolution and also opens up a new avenue for exploring random access memory mechanisms and finding new half-metals for spintronics.

  3. Reverse logistics - a framework

    NARCIS (Netherlands)

    M.P. de Brito (Marisa); R. Dekker (Rommert)

    2002-01-01

    textabstractIn this paper we define and compare Reverse Logistics definitions. We start by giving an understanding framework of Reverse Logistics: the why-what-how. By this means, we put in context the driving forces for Reverse Logistics, a typology of return reasons, a classification of

  4. Tubal Ligation Reversal

    Science.gov (United States)

    ... seal off the fallopian tubes, such as the Essure or Adiana systems, generally aren't reversible. Why ... electrocautery). Some types of sterilization, such as the Essure or Adiana systems, aren't considered reversible. Risks ...

  5. Acoustic Longitudinal Field NIF Optic Feature Detection Map Using Time-Reversal & MUSIC

    Energy Technology Data Exchange (ETDEWEB)

    Lehman, S K

    2006-02-09

    We developed an ultrasonic longitudinal field time-reversal and MUltiple SIgnal Classification (MUSIC) based detection algorithm for identifying and mapping flaws in fused silica NIF optics. The algorithm requires a fully multistatic data set, that is one with multiple, independently operated, spatially diverse transducers, each transmitter of which, in succession, launches a pulse into the optic and the scattered signal measured and recorded at every receiver. We have successfully localized engineered ''defects'' larger than 1 mm in an optic. We confirmed detection and localization of 3 mm and 5 mm features in experimental data, and a 0.5 mm in simulated data with sufficiently high signal-to-noise ratio. We present the theory, experimental results, and simulated results.

  6. Platelet rich fibrin in jaw defects

    Science.gov (United States)

    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.

  7. Little string origin of surface defects

    Energy Technology Data Exchange (ETDEWEB)

    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.

  8. First-Principles Investigations of Defects in Minerals

    Science.gov (United States)

    Verma, Ashok K.

    2011-07-01

    The ideal crystal has an infinite 3-dimensional repetition of identical units which may be atoms or molecules. But real crystals are limited in size and they have disorder in stacking which as called defects. Basically three types of defects exist in solids: 1) point defects, 2) line defects, and 3) surface defects. Common point defects are vacant lattice sites, interstitial atoms and impurities and these are known to influence strongly many solid-state transport properties such as diffusion, electrical conduction, creep, etc. In thermal equilibrium point defects concentrations are determined by their formation enthalpies and their movement by their migration barriers. Line and surface defects are though absent from the ideal crystal in thermal equilibrium due to higher energy costs but they are invariably present in all real crystals. Line defects include edge-, screw- and mixed-dislocations and their presence is essential in explaining the mechanical strength and deformation of real crystals. Surface defects may arise at the boundary between two grains, or small crystals, within a larger crystal. A wide variety of grain boundaries can form in a polycrystal depending on factors such growth conditions and thermal treatment. In this talk we will present our first-principles density functional theory based defect studies of SiO2 polymorphs (stishovite, CaCl2-, α-PbO2-, and pyrite-type), Mg2SiO4 polymorphs (forsterite, wadsleyite and ringwoodite) and MgO [1-3]. Briefly, several native point defects including vacancies, interstitials, and their complexes were studied in silica polymorphs upto 200 GPa. Their values increase by a factor of 2 over the entire pressure range studied with large differences in some cases between different phases. The Schottky defects are energetically most favorable at zero pressure whereas O-Frenkel pairs become systematically more favorable at pressures higher than 20 GPa. The geometric and electronic structures of defects and migrating

  9. Various Stone-Wales defects in phagraphene

    Science.gov (United States)

    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.

  10. Quantum computing with defects.

    Science.gov (United States)

    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.

  11. Charged Semiconductor Defects Structure, Thermodynamics and Diffusion

    CERN Document Server

    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...

  12. 49 CFR 230.89 - Reverse gear.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Reverse gear. 230.89 Section 230.89 Transportation... Reversing Gear § 230.89 Reverse gear. (a) General provisions. Reverse gear, reverse levers, and quadrants... quadrant. Proper counterbalance shall be provided for the valve gear. (b) Air-operated power reverse gear...

  13. Syndromes and Disorders Associated with Omphalocele (III: Single Gene Disorders, Neural Tube Defects, Diaphragmatic Defects and Others

    Directory of Open Access Journals (Sweden)

    Chih-Ping Chen

    2007-06-01

    Full Text Available Omphalocele can be associated with single gene disorders, neural tube defects, diaphragmatic defects, fetal valproate syndrome, and syndromes of unknown etiology. This article provides a comprehensive review of omphalocele-related disorders: otopalatodigital syndrome type II; Melnick–Needles syndrome; Rieger syndrome; neural tube defects; Meckel syndrome; Shprintzen–Goldberg omphalocele syndrome; lethal omphalocele-cleft palate syndrome; cerebro-costo-mandibular syndrome; fetal valproate syndrome; Marshall–Smith syndrome; fibrochondrogenesis; hydrolethalus syndrome; Fryns syndrome; omphalocele, diaphragmatic defects, radial anomalies and various internal malformations; diaphragmatic defects, limb deficiencies and ossification defects of skull; Donnai–Barrow syndrome; CHARGE syndrome; Goltz syndrome; Carpenter syndrome; Toriello–Carey syndrome; familial omphalocele; Cornelia de Lange syndrome; C syndrome; Elejalde syndrome; Malpuech syndrome; cervical ribs, Sprengel anomaly, anal atresia and urethral obstruction; hydrocephalus with associated malformations; Kennerknecht syndrome; lymphedema, atrial septal defect and facial changes; and craniosynostosis- mental retardation syndrome of Lin and Gettig. Perinatal identification of omphalocele should alert one to the possibility of omphalocele-related disorders and familial inheritance and prompt a thorough genetic counseling for these disorders.

  14. Application of elastic net and infrared spectroscopy in the discrimination between defective and non-defective roasted coffees.

    Science.gov (United States)

    Craig, Ana Paula; Franca, Adriana S; Oliveira, Leandro S; Irudayaraj, Joseph; Ileleji, Klein

    2014-10-01

    The quality of the coffee beverage is negatively affected by the presence of defective coffee beans and its evaluation still relies on highly subjective sensory panels. To tackle the problem of subjectivity, sophisticated analytical techniques have been developed and have been shown capable of discriminating defective from non-defective coffees after roasting. However, these techniques are not adequate for routine analysis, for they are laborious (sample preparation) and time consuming, and reliable, simpler and faster techniques need to be developed for such purpose. Thus, it was the aim of this study to evaluate the performance of infrared spectroscopic methods, namely FTIR and NIR, for the discrimination of roasted defective and non-defective coffees, employing a novel statistical approach. The classification models based on Elastic Net exhibited high percentage of correct classification, and the discriminant infrared spectra variables extracted provided a good interpretation of the models. The discrimination of defective and non-defective beans was associated with main chemical descriptors of coffee, such as carbohydrates, proteins/amino acids, lipids, caffeine and chlorogenic acids. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Magnetoencephalography signals are influenced by skull defects.

    Science.gov (United States)

    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.

  16. Reversible Communicating Processes

    Directory of Open Access Journals (Sweden)

    Geoffrey Brown

    2016-02-01

    Full Text Available Reversible distributed programs have the ability to abort unproductive computation paths and backtrack, while unwinding communication that occurred in the aborted paths. While it is natural to assume that reversibility implies full state recovery (as with traditional roll-back recovery protocols, an interesting alternative is to separate backtracking from local state recovery. For example, such a model could be used to create complex transactions out of nested compensable transactions where a programmer-supplied compensation defines the work required to "unwind" a transaction. Reversible distributed computing has received considerable theoretical attention, but little reduction to practice; the few published implementations of languages supporting reversibility depend upon a high degree of central control. The objective of this paper is to demonstrate that a practical reversible distributed language can be efficiently implemented in a fully distributed manner. We discuss such a language, supporting CSP-style synchronous communication, embedded in Scala. While this language provided the motivation for the work described in this paper, our focus is upon the distributed implementation. In particular, we demonstrate that a "high-level" semantic model can be implemented using a simple point-to-point protocol.

  17. Electrical fingerprint of pipeline defects

    International Nuclear Information System (INIS)

    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

  18. Defect spectroscopy of single ZnO microwires

    Science.gov (United States)

    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.

  19. Impurity Role In Mechanically Induced Defects

    International Nuclear Information System (INIS)

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

    2000-01-01

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

  20. Defect properties from X-ray scattering experiments

    International Nuclear Information System (INIS)

    Peisl, H.

    1976-01-01

    Lattice distortions due to defects in crystals can be studied most directly by elastic X-ray or neutron scattering experiments. The 'size' of the defects can be determined from the shift of the Bragg reflections. Defect induced diffuse scattering intensity close to and between Bragg reflections gives information on the strength and symmetry of the distortion fields and yields the atomic structure of point defects (interstitials, vacancies, small aggregates). Diffuse scattering is a very sensitive method to decide whether defects are present as isolated point defects or have formed aggregates. X-ray scattering has been used to study defects produced in various ionic crystals by γ- and neutron irradiation. After an introduction to the principles of the method the experimental results will be reviewed and discussed in some detail. (orig.) [de

  1. Modeling of Powder Bed Manufacturing Defects

    Science.gov (United States)

    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.

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

    International Nuclear Information System (INIS)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  4. The Geomagnetic Field During a Reversal

    Science.gov (United States)

    Heirtzler, James R.

    2003-01-01

    By modifying the IGRF it is possible to learn what may happen to the geomagnetic field during a geomagnetic reversal. If the entire IGRF reverses then the declination and inclination only reverse when the field strength is zero. If only the dipole component of the IGRF reverses a large geomagnetic field remains when the dipole component is zero and he direction of the field at the end of the reversal is not exactly reversed from the directions at the beginning of the reversal.

  5. Congenital heart defects in Williams syndrome.

    Science.gov (United States)

    Yuan, Shi-Min

    2017-01-01

    Yuan SM. Congenital heart defects in Williams syndrome. Turk J Pediatr 2017; 59: 225-232. Williams syndrome (WS), also known as Williams-Beuren syndrome, is a rare genetic disorder involving multiple systems including the circulatory system. However, the etiologies of the associated congenital heart defects in WS patients have not been sufficiently elucidated and represent therapeutic challenges. The typical congenital heart defects in WS were supravalvar aortic stenosis, pulmonary stenosis (both valvular and peripheral), aortic coarctation and mitral valvar prolapse. The atypical cardiovascular anomalies include tetralogy of Fallot, atrial septal defects, aortic and mitral valvular insufficiencies, bicuspid aortic valves, ventricular septal defects, total anomalous pulmonary venous return, double chambered right ventricle, Ebstein anomaly and arterial anomalies. Deletion of the elastin gene on chromosome 7q11.23 leads to deficiency or abnormal deposition of elastin during cardiovascular development, thereby leading to widespread cardiovascular abnormalities in WS. In this article, the distribution, treatment and surgical outcomes of typical and atypical cardiac defects in WS are discussed.

  6. Secondary defects in non-metallic solids

    International Nuclear Information System (INIS)

    Ashbee, K.H.G.; Hobbs, L.W.

    1977-01-01

    This paper points out features of secondary defect formation which are peculiar to non-metallic solids (excluding elemental semiconductors). Most of the materials of interest are compounds of two or more (usually more or less ionic) atomic species, and immediate consequence of which is a need to maintain both stoichiometry (or accommodate non-stoichiometry) and order. Primary defects in these solids, whether produced thermally, chemically or by irradiation, seldom are present or aggregate in exactly stoichiometric proportions, and the resulting extending defect structures can be quite distinct from those found in metallic solids. Where stoichiometry is maintained, it is often convenient to describe extended defects in terms of alterations in the arrangement of 'molecular' units. The adoption of this procedure enables several novel features of extended defect structures in non-metals to be explained. There are several ways in which a range of non-stoichiometry can be accommodated, which include structural elimination of point defects, nucleation of new coherent phases of altered stoichiometry, and decomposition. (author)

  7. Defect localization, characterization and reliability assessment in emerging photovoltaic devices.

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Benjamin Bing-Yeh [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Cruz-Campa, Jose Luis [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Haase, Gad S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Tangyunyong, Paiboon [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Colr, Edward Isaac [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Okandan, Murat [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Nielson, Gregory N. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-04-01

    Microsystems-enabled photovoltaics (MEPV) can potentially meet increasing demands for light-weight, portable, photovoltaic solutions with high power density and efficiency. The study in this report examines failure analysis techniques to perform defect localization and evaluate MEPV modules. CMOS failure analysis techniques, including electroluminescence, light-induced voltage alteration, thermally-induced voltage alteration, optical beam induced current, and Seabeck effect imaging were successfully adapted to characterize MEPV modules. The relative advantages of each approach are reported. In addition, the effects of exposure to reverse bias and light stress are explored. MEPV was found to have good resistance to both kinds of stressors. The results form a basis for further development of failure analysis techniques for MEPVs of different materials systems or multijunction MEPVs. The incorporation of additional stress factors could be used to develop a reliability model to generate lifetime predictions for MEPVs as well as uncover opportunities for future design improvements.

  8. Defining defect specifications to optimize photomask production and requalification

    Science.gov (United States)

    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.

  9. Metastable and bistable defects in silicon

    International Nuclear Information System (INIS)

    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)

  10. Topological defects in extended inflation

    International Nuclear Information System (INIS)

    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

  11. Topological defects in extended inflation

    International Nuclear Information System (INIS)

    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

  12. Defect accumulation under cascade damage conditions

    DEFF Research Database (Denmark)

    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...

  13. Building defects in Danish construction: project characteristics influencing the occurrence of defects at handover

    DEFF Research Database (Denmark)

    Schultz, Casper Siebken; Jørgensen, Kirsten; Bonke, Sten

    2015-01-01

    Defects in construction have gained much attention from both the public and academia. Danish construction is no exception and a number of political initiatives have been established to address the unsatisfying amounts of defects. One of the political initiatives, benchmarking, collects and provides...... those with many and/or serious defects. The article reviews the results from studying two quantitative data sets: (I) benchmarking data from 329 building projects and 621 contracts and (II) questionnaire data from an electronic survey comprising 130 contractors. This study provides in-depth knowledge...

  14. Quantum computing with defects

    Science.gov (United States)

    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.

  15. Defect States in InP/InGaAs/InP Heterostructures by Current-Voltage Characteristics and Deep Level Transient Spectroscopy.

    Science.gov (United States)

    Vu, Thi Kim Oanh; Lee, Kyoung Su; Lee, Sang Jun; Kim, Eun Kyu

    2018-09-01

    We studied defect states in In0.53Ga0.47As/InP heterojunctions with interface control by group V atoms during metalorganic chemical vapor (MOCVD) deposition. From deep level transient spectroscopy (DLTS) measurements, two defects with activation energies of 0.28 eV (E1) and 0.15 eV (E2) below the conduction band edge, were observed. The defect density of E1 for In0.53Ga0.47As/InP heterojunctions with an addition of As and P atoms was about 1.5 times higher than that of the heterojunction added P atom only. From the temperature dependence of current- voltage characteristics, the thermal activation energies of In0.53Ga0.47As/InP of heterojunctions were estimated to be 0.27 and 0.25 eV, respectively. It appeared that the reverse light current for In0.53Ga0.47As/InP heterojunction added P atom increased only by illumination of a 940 nm-LED light source. These results imply that only the P addition at the interface can enhance the quality of InGaAs/InP heterojunction.

  16. Defect identification using positrons

    International Nuclear Information System (INIS)

    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.)

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

    International Nuclear Information System (INIS)

    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

  18. Electronic structure of point defects in semiconductors

    International Nuclear Information System (INIS)

    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

  19. Point defects and atomic transport in crystals

    International Nuclear Information System (INIS)

    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

  20. Antigravity from a spacetime defect

    OpenAIRE

    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."

  1. Sub-surface defect detection using transient thermography

    International Nuclear Information System (INIS)

    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)

  2. Muscular activation during reverse and non-reverse chewing cycles in unilateral posterior crossbite.

    Science.gov (United States)

    Piancino, Maria Grazia; Farina, Dario; Talpone, Francesca; Merlo, Andrea; Bracco, Pietro

    2009-04-01

    The aim of this study was to characterize the kinematics and masseter muscle activation in unilateral posterior crossbite. Eighty-two children (8.6 +/- 1.3 yr of age) with unilateral posterior crossbite and 12 children (8.9 +/- 0.6 yr of age) with normal occlusion were selected for the study. Electromyography (EMG) and kinematics were concurrently recorded during mastication of a soft bolus and a hard bolus. The percentage of reverse cycles in the group of patients was 59.0 +/- 33.1% (soft bolus) and 69.7 +/- 29.7% (hard bolus) when chewing on the crossbite side. When chewing on the non-affected side, the number of reverse cycles was 16.7 +/- 24.5% (soft bolus) and 16.7 +/- 22.3% (hard bolus). The reverse cycles on the crossbite side were narrower with respect to the cycles on the non-affected side. Although both types of cycles in patients resulted in lower EMG activity of the masseter of the crossbite side than of the contralateral masseter, the activity of the non-affected side was larger for reverse than for non-reverse cycles. It was concluded that when chewing on the crossbite side, the masseter activity is reduced on the mastication side (crossbite) and is unaltered (non-reverse cycles) or increased (reverse) on the non-affected side.

  3. AMPK Activation Prevents and Reverses Drug-Induced Mitochondrial and Hepatocyte Injury by Promoting Mitochondrial Fusion and Function.

    Directory of Open Access Journals (Sweden)

    Sun Woo Sophie Kang

    Full Text Available Mitochondrial damage is the major factor underlying drug-induced liver disease but whether conditions that thwart mitochondrial injury can prevent or reverse drug-induced liver damage is unclear. A key molecule regulating mitochondria quality control is AMP activated kinase (AMPK. When activated, AMPK causes mitochondria to elongate/fuse and proliferate, with mitochondria now producing more ATP and less reactive oxygen species. Autophagy is also triggered, a process capable of removing damaged/defective mitochondria. To explore whether AMPK activation could potentially prevent or reverse the effects of drug-induced mitochondrial and hepatocellular damage, we added an AMPK activator to collagen sandwich cultures of rat and human hepatocytes exposed to the hepatotoxic drugs, acetaminophen or diclofenac. In the absence of AMPK activation, the drugs caused hepatocytes to lose polarized morphology and have significantly decreased ATP levels and viability. At the subcellular level, mitochondria underwent fragmentation and had decreased membrane potential due to decreased expression of the mitochondrial fusion proteins Mfn1, 2 and/or Opa1. Adding AICAR, a specific AMPK activator, at the time of drug exposure prevented and reversed these effects. The mitochondria became highly fused and ATP production increased, and hepatocytes maintained polarized morphology. In exploring the mechanism responsible for this preventive and reversal effect, we found that AMPK activation prevented drug-mediated decreases in Mfn1, 2 and Opa1. AMPK activation also stimulated autophagy/mitophagy, most significantly in acetaminophen-treated cells. These results suggest that activation of AMPK prevents/reverses drug-induced mitochondrial and hepatocellular damage through regulation of mitochondrial fusion and autophagy, making it a potentially valuable approach for treatment of drug-induced liver injury.

  4. AMPK Activation Prevents and Reverses Drug-Induced Mitochondrial and Hepatocyte Injury by Promoting Mitochondrial Fusion and Function

    Science.gov (United States)

    Taniane, Caitlin; Farrell, Geoffrey; Arias, Irwin M.; Lippincott-Schwartz, Jennifer; Fu, Dong

    2016-01-01

    Mitochondrial damage is the major factor underlying drug-induced liver disease but whether conditions that thwart mitochondrial injury can prevent or reverse drug-induced liver damage is unclear. A key molecule regulating mitochondria quality control is AMP activated kinase (AMPK). When activated, AMPK causes mitochondria to elongate/fuse and proliferate, with mitochondria now producing more ATP and less reactive oxygen species. Autophagy is also triggered, a process capable of removing damaged/defective mitochondria. To explore whether AMPK activation could potentially prevent or reverse the effects of drug-induced mitochondrial and hepatocellular damage, we added an AMPK activator to collagen sandwich cultures of rat and human hepatocytes exposed to the hepatotoxic drugs, acetaminophen or diclofenac. In the absence of AMPK activation, the drugs caused hepatocytes to lose polarized morphology and have significantly decreased ATP levels and viability. At the subcellular level, mitochondria underwent fragmentation and had decreased membrane potential due to decreased expression of the mitochondrial fusion proteins Mfn1, 2 and/or Opa1. Adding AICAR, a specific AMPK activator, at the time of drug exposure prevented and reversed these effects. The mitochondria became highly fused and ATP production increased, and hepatocytes maintained polarized morphology. In exploring the mechanism responsible for this preventive and reversal effect, we found that AMPK activation prevented drug-mediated decreases in Mfn1, 2 and Opa1. AMPK activation also stimulated autophagy/mitophagy, most significantly in acetaminophen-treated cells. These results suggest that activation of AMPK prevents/reverses drug-induced mitochondrial and hepatocellular damage through regulation of mitochondrial fusion and autophagy, making it a potentially valuable approach for treatment of drug-induced liver injury. PMID:27792760

  5. Insulin resistance, insulin sensitization and inflammation in polycystic ovarian syndrome

    Directory of Open Access Journals (Sweden)

    Dhindsa G

    2004-04-01

    Full Text Available It is estimated that 5-10% of women of reproductive age have polycystic ovarian syndrome (PCOS. While insulin resistance is not part of the diagnostic criteria for PCOS, its importance in the pathogenesis of PCOS cannot be denied. PCOS is associated with insulin resistance independent of total or fat-free body mass. Post-receptor defects in the action of insulin have been described in PCOS which are similar to those found in obesity and type 2 diabetes. Treatment with insulin sensitizers, metformin and thiazolidinediones, improve both metabolic and hormonal patterns and also improve ovulation in PCOS. Recent studies have shown that PCOS women have higher circulating levels of inflammatory mediators like C-reactive protein, tumour necrosis factor- , tissue plasminogen activator and plasminogen activator inhibitor-1 (PAI-1 . It is possible that the beneficial effect of insulin sensitizers in PCOS may be partly due to a decrease in inflammation.

  6. The Causes of Preference Reversal.

    OpenAIRE

    Tversky, Amos; Slovic, Paul; Kahneman, Daniel

    1990-01-01

    Observed preference reversal cannot be adequately explained by violations of independence, the reduction axiom, or transitivity. The primary cause of preference reversal is the failure of procedure invariance, especially the overpricing of low-probability, high-payoff bets. This result violates regret theory and generalized (nonindependent) utility models. Preference reversal and a new reversal involving time preferences are explained by scale compatibility, which implies that payoffs are wei...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-04-01

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

  8. Computer programs for eddy-current defect studies

    Energy Technology Data Exchange (ETDEWEB)

    Pate, J. R.; Dodd, C. V. [Oak Ridge National Lab., TN (USA)

    1990-06-01

    Several computer programs to aid in the design of eddy-current tests and probes have been written. The programs, written in Fortran, deal in various ways with the response to defects exhibited by four types of probes: the pancake probe, the reflection probe, the circumferential boreside probe, and the circumferential encircling probe. Programs are included which calculate the impedance or voltage change in a coil due to a defect, which calculate and plot the defect sensitivity factor of a coil, and which invert calculated or experimental readings to obtain the size of a defect. The theory upon which the programs are based is the Burrows point defect theory, and thus the calculations of the programs will be more accurate for small defects. 6 refs., 21 figs.

  9. Computer programs for eddy-current defect studies

    International Nuclear Information System (INIS)

    Pate, J.R.; Dodd, C.V.

    1990-06-01

    Several computer programs to aid in the design of eddy-current tests and probes have been written. The programs, written in Fortran, deal in various ways with the response to defects exhibited by four types of probes: the pancake probe, the reflection probe, the circumferential boreside probe, and the circumferential encircling probe. Programs are included which calculate the impedance or voltage change in a coil due to a defect, which calculate and plot the defect sensitivity factor of a coil, and which invert calculated or experimental readings to obtain the size of a defect. The theory upon which the programs are based is the Burrows point defect theory, and thus the calculations of the programs will be more accurate for small defects. 6 refs., 21 figs

  10. Exploring atomic defects in molybdenum disulphide monolayers

    KAUST Repository

    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.

  11. Areva solutions for management of defective fuel

    International Nuclear Information System (INIS)

    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. Exploring atomic defects in molybdenum disulphide monolayers

    KAUST Repository

    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.

  13. Defect-impurity interactions in ion-implanted metals

    International Nuclear Information System (INIS)

    Turos, A.

    1986-01-01

    An overview of defect-impurity interactions in metals is presented. When point defects become mobile they migrate towards the sinks and on the way can be captured by impurity atoms forming stable associations so-called complexes. In some metallic systems complexes can also be formed athermally during ion implantation by trapping point defects already in the collision cascade. An association of a point defect with an impurity atom leads to its displacement from the lattice site. The structure and stability of complexes are strongly temperature dependent. With increasing temperature they dissociate or grow by multiple defect trapping. The appearance of freely migrating point defects at elevated temperatures, due to ion bombardment or thermal annealing, causes via coupling with defect fluxes, important impurity redistribution. Because of the sensitivity of many metal-in-metal implanted systems to radiation damage the understanding of this processes is essential for a proper interpretation of the lattice occupancy measurements and the optimization of implantation conditions. (author)

  14. Congenital Heart Defects (For Parents)

    Science.gov (United States)

    ... to be associated with genetic disorders, such as Down syndrome . But the cause of most congenital heart defects isn't known. While they can't be prevented, many treatments are available for the defects and related health ...

  15. Ultra-selective defect-free interfacially polymerized molecular sieve thin-film composite membranes for H2 purification

    KAUST Repository

    Ali, Zain

    2017-10-10

    Purification is a major bottleneck towards generating low-cost commercial hydrogen. In this work, inexpensive high-performance H2 separating membranes were fabricated by modifying the commercially successful interfacial polymerization production method for reverse osmosis membranes. Defect-free thin-film composite membranes were formed demonstrating unprecedented mixed-gas H2/CO2 selectivity of ≈ 50 at 140 °C with H2 permeance of 350 GPU, surpassing the permeance/selectivity upper bound of all known polymer membranes by a wide margin. The combination of exceptional separation performance and low manufacturing cost makes them excellent candidates for cost-effective hydrogen purification from steam cracking and similar processes.

  16. Surface magnetization and the role of pattern defects in various types of ripple patterned films

    International Nuclear Information System (INIS)

    Colino, Jose M; Arranz, Miguel A; Barbero, Antonio J; Bollero, A; Camarero, J

    2016-01-01

    We present a detailed study of the magnetic properties of cobalt films with wide-area nanoscale ripple patterns, either on their surface only, or on both the film surface and substrate interface. Angular dependence vectorial-resolved magnetometry measurements and magnetic force microscopy with in situ magnetic field have been used to determine the magnetization reversal processes to correlate them to the different patterned nanostructures. All the samples show well-defined uniaxial magnetic anisotropy with the anisotropy axis lying along the ripple direction. Atomic force microscopy of the different types of pattern reveals various pattern defects: height corrugation and breaks of continuity along the ripple direction, and overlapping ripples and Y-shaped defects (pattern dislocation) across the pattern. In spite of the existence of such customary defects of erosive-regime patterns, the type of low-amplitude, surface-patterned films remarkably behave as a macrospin over almost the whole in-plane angular range (340°), with negligible spread of anisotropy axis or energy. In turn, it is found that high-amplitude surface-patterned films develop an angular distribution of anisotropy axes, probably related to the large distribution of amplitudes in a pattern of short ripples, and a significant distribution of anisotropy fields ΔH k /H k up to 15%. On the other hand, films grow on pre-patterned silicon with a significantly longer mean ripple length, and develop a larger anisotropy energy with H k up to 110 mT, probably because of the double interface effect. The switching fields close to the magnetization easy axis of all types of ripple pattern are not well reproduced by the macrospin approximation, but the observed pattern defects seem to be not responsible for the domain wall pinning that occurs with the field applied along the ripple direction. (paper)

  17. Momentum conserving defects in affine Toda field theories

    Energy Technology Data Exchange (ETDEWEB)

    Bristow, Rebecca; Bowcock, Peter [Department of Mathematical Sciences, Durham University,Durham, DH1 3LE (United Kingdom)

    2017-05-30

    Type II integrable defects with more than one degree of freedom at the defect are investigated. A condition on the form of the Lagrangian for such defects is found which ensures the existence of a conserved momentum in the presence of the defect. In addition it is shown that for any Lagrangian satisfying this condition, the defect equations of motion, when taken to hold everywhere, can be extended to give a Bäcklund transformation between the bulk theories on either side of the defect. This strongly suggests that such systems are integrable. Momentum conserving defects and Bäcklund transformations for affine Toda field theories based on the A{sub n}, B{sub n}, C{sub n} and D{sub n} series of Lie algebras are found. The defect associated with the D{sub 4} affine Toda field theory is examined in more detail. In particular classical time delays for solitons passing through the defect are calculated.

  18. Dual approaches for defects condensation

    Energy Technology Data Exchange (ETDEWEB)

    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)

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

    Science.gov (United States)

    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.

  20. Defects in conformal field theory

    International Nuclear Information System (INIS)

    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.

  1. Defects in conformal field theory

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. Bilateral Epithelial Defects after Laser in situ Keratomileusis. Clinical Features, Management and Outcome

    Directory of Open Access Journals (Sweden)

    Rao Srinivas

    2005-03-01

    Full Text Available PURPOSE: To describe the preoperative characteristics, intraoperative details, management, and postoperative in patients with bilateral epithelial defects after laser in situ keratomileusis (LASIK. METHODS: Retrospective non-comparative case series. RESULTS: Six patients with bilateral epithelial defects after LAISK were part of a cohort of 605 patients undergoing bilateral LASIK at our center from December 2001 to April 2003. The mean age of the patients (5M:1F was 28.5 7.9 years, and the average pretreatment myopic spherical equivalent (SE refraction was 7.3 0.7 D (-4, -12.25D. An epithelial flap was present in 6 eyes and an epithelial defect with a mean diameter of 3 mm (2mm, 6mm was seen in 6 eyes. In four patients the epithelial disturbance was bilaterally similar. All defects occurred in the inferior cornea and the epithelial flaps had the hinge positioned superiorly. None of the patients had ocular or systemic risk factors that could have resulted in this complication. A bandage contact lens was used in 6 eyes. At last follow-up of 5.5 9.5 months (0.25, 21 months, unaided visual acuity was 6/9 or better in 10 eyes. Best spectacle-corrected visual acuity (BSCVA was maintained in 8 eyes, while 4 eyes lost one line of BSCVA. Recurrent corneal erosions were not reported in the follow-up period. CONCLUSIONS: These patients represent a hitherto unrecognised group of individuals who appear to have a subclinical weakness of adhesion of the corneal epithelium to the underlying structures, which is not evident on clinical examination. This results in bilateral epithelial disturbances after LASIK. Appropriate management results in satisfactory clinical outcomes. Other options for treatment of the fellow eye of such patients include the use of a different microkeratome, release of suction during the reverse pass of the Hansatome microkeratome, and photorefractive keratectomy if the refractive error is low.

  3. Concurrence of metaphyseal fibrous defect and osteosarcoma

    International Nuclear Information System (INIS)

    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.)

  4. Extrusion product defects: a statistical study

    International Nuclear Information System (INIS)

    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)

  5. Automatic classification of defects in weld pipe

    International Nuclear Information System (INIS)

    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. Primordial inhomogeneities from massive defects during inflation

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. Automatic classification of defects in weld pipe

    International Nuclear Information System (INIS)

    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. Large-Scale Molecular Simulations on the Mechanical Response and Failure Behavior of a defective Graphene: Cases of 5-8-5 Defects

    Science.gov (United States)

    Wang, Shuaiwei; Yang, Baocheng; Yuan, Jinyun; Si, Yubing; Chen, Houyang

    2015-10-01

    Understanding the effect of defects on mechanical responses and failure behaviors of a graphene membrane is important for its applications. As examples, in this paper, a family of graphene with various 5-8-5 defects are designed and their mechanical responses are investigated by employing molecular dynamics simulations. The dependence of fracture strength and strain as well as Young’s moduli on the nearest neighbor distance and defect types is examined. By introducing the 5-8-5 defects into graphene, the fracture strength and strain become smaller. However, the Young’s moduli of DL (Linear arrangement of repeat unit 5-8-5 defect along zigzag-direction of graphene), DS (a Slope angle between repeat unit 5-8-5 defect and zigzag direction of graphene) and DZ (Zigzag-like 5-8-5 defects) defects in the zigzag direction become larger than those in the pristine graphene in the same direction. A maximum increase of 11.8% of Young’s modulus is obtained. Furthermore, the brittle cracking mechanism is proposed for the graphene with 5-8-5 defects. The present work may provide insights in controlling the mechanical properties by preparing defects in the graphene, and give a full picture for the applications of graphene with defects in flexible electronics and nanodevices.

  9. Lectures on cosmic topological defects

    Energy Technology Data Exchange (ETDEWEB)

    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)

  10. Electronic and optical properties of vacancy defects in single-layer transition metal dichalcogenides

    Science.gov (United States)

    Khan, M. A.; Erementchouk, Mikhail; Hendrickson, Joshua; Leuenberger, Michael N.

    2017-06-01

    A detailed first-principles study has been performed to evaluate the electronic and optical properties of single-layer (SL) transition metal dichalcogenides (TMDCs) (M X 2 ; M = transition metal such as Mo, W, and X = S, Se, Te), in the presence of vacancy defects (VDs). Defects usually play an important role in tailoring electronic, optical, and magnetic properties of semiconductors. We consider three types of VDs in SL TMDCs: (i) X vacancy, (ii) X2 vacancy, and (iii) M vacancy. We show that VDs lead to localized defect states (LDS) in the band structure, which in turn gives rise to sharp transitions in in-plane and out-of-plane optical susceptibilities, χ∥ and χ⊥. The effects of spin-orbit coupling (SOC) are also considered. We find that SOC splitting in LDS is directly related to the atomic number of the transition metal atoms. Apart from electronic and optical properties we also find magnetic signatures (local magnetic moment of ˜μB ) in MoSe2 in the presence of the Mo vacancy, which breaks the time-reversal symmetry and therefore lifts the Kramers degeneracy. We show that a simple qualitative tight-binding model (TBM), involving only the hopping between atoms surrounding the vacancy with an on-site SOC term, is sufficient to capture the essential features of LDS. In addition, the existence of the LDS can be understood from the solution of the two-dimensional Dirac Hamiltonian by employing infinite mass boundary conditions. In order to provide a clear description of the optical absorption spectra, we use group theory to derive the optical selection rules between LDS for both χ∥ and χ⊥.

  11. Reverse logistics policy – differences between conservative and innovative reverse logistics management

    Directory of Open Access Journals (Sweden)

    Alena Klapalová

    2013-01-01

    Full Text Available One of the of the key barriers that hampers effective and efficient management of reverse flows detected within a number of empirical surveys and case studies focused on reverse logistics and/or return management is business (organisational policy, specifically lack of policy, deficiency in existing policy or inferior policy. Despite this fact, there is a gap in literature which would show some evidence from practice that innovative reverse logistics policy both can pay off and is associated with certain aspects of reverse logistics management. Such proof can have several implications. It can support the call for better understanding and more research of the linkages of reverse logistics with other corporate functions, promote the acceptation of strategic character of reverse logistics and stress the role of RL policy within the rest of overall corporate management.The aim of this paper is to contribute and to enrich the existing body of knowledge concerning the above-mentioned gap through presentation of survey results that was realized in 2012 among managers of 244 Czech firms. The results demonstrate the statistically significant association between the innovativeness of RL policy and profitability of firms, quality of RL planning, perception of RL importance, level of RL knowledge and perception of product innovation importance for firms’ competitiveness and frequency of product innovation. They also reveal statistically significant differences between firms with conservative and innovative RL policy and the perceived existence of some barriers to manage RL.

  12. Geomagnetic Field During a Reversal

    Science.gov (United States)

    Heirtzler, J. R.

    2003-01-01

    It has frequently been suggested that only the geomagnetic dipole, rather than higher order poles, reverse during a geomagnetic field reversal. Under this assumption the geomagnetic field strength has been calculated for the surface of the Earth for various steps of the reversal process. Even without an eminent a reversal of the field, extrapolation of the present secular change (although problematic) shows that the field strength may become zero in some geographic areas within a few hundred years.

  13. Defect-Tolerant Monolayer Transition Metal Dichalcogenides

    DEFF Research Database (Denmark)

    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...

  14. Production of freely-migrating defects during irradiation

    International Nuclear Information System (INIS)

    Rehn, L.E.; Okamoto, P.R.

    1986-09-01

    During irradiation at elevated temperatures, vacancy and interstitial defects that escape can produce several different types of microstructural changes. Hence the production rate of freely-migrating defects must be known as a function of irradiating particle species and energy before quantitative correlations can be made between microstructural changes. Our fundamental knowledge of freely-migrating defect production has increased substantially in recent years. Critical experimental findings that led to the improved understanding are reviewed in this paper. A strong similarity is found for the dependence of freely-migrating defect production on primary recoil energy as measured in a variety of metals and alloys by different authors. The efficiency for producing freely-migrating defects decreases much more strongly with increasing primary recoil energy than does the efficiency for creating stable defects at liquid helium temperatures. The stronger decrease can be understood in terms of additional intracascade recombination that results from the nonrandom distribution of defects existing in the primary damage state for high primary recoil energies. Although the existing data base is limited to fcc materials, the strong similarity in the reported investigations suggests that the same dependence of freely-migrating defect production on primary recoil energy may be characteristic of a wide variety of other alloy systems as well. 52 refs., 4 figs

  15. Human diseases associated with defective DNA repair

    International Nuclear Information System (INIS)

    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

  16. Defect identification for the AsGa family

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

    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.

  18. Altering graphene line defect properties using chemistry

    Science.gov (United States)

    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.

  19. Supercritical fluid reverse micelle separation

    Science.gov (United States)

    Fulton, J.L.; Smith, R.D.

    1993-11-30

    A method of separating solute material from a polar fluid in a first polar fluid phase is provided. The method comprises combining a polar fluid, a second fluid that is a gas at standard temperature and pressure and has a critical density, and a surfactant. The solute material is dissolved in the polar fluid to define the first polar fluid phase. The combined polar and second fluids, surfactant, and solute material dissolved in the polar fluid is maintained under near critical or supercritical temperature and pressure conditions such that the density of the second fluid exceeds the critical density thereof. In this way, a reverse micelle system defining a reverse micelle solvent is formed which comprises a continuous phase in the second fluid and a plurality of reverse micelles dispersed in the continuous phase. The solute material is dissolved in the polar fluid and is in chemical equilibrium with the reverse micelles. The first polar fluid phase and the continuous phase are immiscible. The reverse micelles each comprise a dynamic aggregate of surfactant molecules surrounding a core of the polar fluid. The reverse micelle solvent has a polar fluid-to-surfactant molar ratio W, which can vary over a range having a maximum ratio W[sub o] that determines the maximum size of the reverse micelles. The maximum ratio W[sub o] of the reverse micelle solvent is then varied, and the solute material from the first polar fluid phase is transported into the reverse micelles in the continuous phase at an extraction efficiency determined by the critical or supercritical conditions. 27 figures.

  20. Iatrogenic Urethral Defect Repairment: A Case Report

    Directory of Open Access Journals (Sweden)

    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.

  1. r-Universal reversible logic gates

    International Nuclear Information System (INIS)

    Vos, A de; Storme, L

    2004-01-01

    Reversible logic plays a fundamental role both in ultra-low power electronics and in quantum computing. It is therefore important to know which reversible logic gates can be used as building block for the reversible implementation of an arbitrary boolean function and which cannot

  2. Repairing Nanoparticle Surface Defects.

    Science.gov (United States)

    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.

  3. Quantum reverse hypercontractivity

    Energy Technology Data Exchange (ETDEWEB)

    Cubitt, Toby [Department of Computer Science, University College London, London, United Kingdom and Centre for Quantum Information and Foundations, DAMTP, University of Cambridge, Cambridge (United Kingdom); Kastoryano, Michael [NBIA, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark); Montanaro, Ashley [School of Mathematics, University of Bristol, Bristol (United Kingdom); Temme, Kristan [Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125 (United States)

    2015-10-15

    We develop reverse versions of hypercontractive inequalities for quantum channels. By generalizing classical techniques, we prove a reverse hypercontractive inequality for tensor products of qubit depolarizing channels. We apply this to obtain a rapid mixing result for depolarizing noise applied to large subspaces and to prove bounds on a quantum generalization of non-interactive correlation distillation.

  4. Introduction to reversible computing

    CERN Document Server

    Perumalla, Kalyan S

    2013-01-01

    Few books comprehensively cover the software and programming aspects of reversible computing. Filling this gap, Introduction to Reversible Computing offers an expanded view of the field that includes the traditional energy-motivated hardware viewpoint as well as the emerging application-motivated software approach. Collecting scattered knowledge into one coherent account, the book provides a compendium of both classical and recently developed results on reversible computing. It explores up-and-coming theories, techniques, and tools for the application of rever

  5. A Study on Reverse Logistics

    OpenAIRE

    Reddy, Dhananjaya

    2011-01-01

    In the competitive world of manufacturing, companies are often searching for new ways to improve their process, customer satisfaction and stay ahead in the game with their competitors. Reverse logistics has been considered a strategy to bring these things to life for the past decade or so. This thesis work tries to shed some light on the basics of reverse logistics and how reverse logistics can be used as a management strategy. This paper points out the fundamentals of reverse logistics and l...

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

    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.

  8. False-positive defects in technetium-99m sestamibi myocardial single-photon emission tomography in healthy athletes with left ventricular hypertrophy

    International Nuclear Information System (INIS)

    Bartram, P.; Hanel, B.; Gustafsson, F.; Mortensen, J.; Hesse, B.; Toft, J.; Ali, S.

    1998-01-01

    Exercise ECG and myocardial single-photon emission tomography (SPET) are fundamental in the non-invasive evaluation of patients suspected of having coronary artery disease (CAD). The purpose of the present study was to investigate the influence of physiological left ventricular hypertrophy (LVH) on myocardial sestamibi SPET in healthy young and old athletes. Eighteen young male elite athletes (ten rowers, five power/weight lifters and three triathletes) and 14 well-trained elderly rowers were studied. All underwent a bicycle test as part of a 2-day sestamibi SPET protocol. Attenuation correction was not performed. The studies were evaluated visually and quantitatively analysed by the CEqual program with its reference files and with a file from a local non-athletic age-matched population. Echocardiographic LVH was an inclusion criterion in the young athletes. Exercise ECG was normal in all subjects. In at least three of the young athletes a reversible defect was observed by visual analysis. On quantitative analysis one-third of the young athletes had ''significant'' (>10 pixels) defects compared with both the local reference base and the CEqual reference population. Nearly all defects were found in the anterior or inferior wall. The remaining subjects, including all old rowers, had normal SPET findings. Anterior and inferior wall defects are so common in healthy athletes with physiological LVH that the specificity of myocardial SPET, in contrast to exercise ECG, seems to be too low for evaluation of chest pain in this group. The mechanism of anterior and inferior defects may be related to hot spots (papillary muscles?) in the lateral wall. The specificity of SPET is maintained in athletes without LVH. (orig.)

  9. Defect engineering of SrTiO3 thin films for resistive switching applications

    International Nuclear Information System (INIS)

    Wicklein, Sebastian

    2013-01-01

    switching properties of SrTiO 3 was investigated by local conductivity AFM. Defect engineered SrTiO 3 depict variations of the resistive switching properties for different defect constellations within the system. More stable resistance switching was achieved for systems with an increased defect content. The mechanism of the resistance change was attributed to the rearrangement of oxygen vacancies within SrTiO 3 and a theory devised where the rearrangement of the oxygen vacancies causes a reversible transition of the oxide from p- to n-type. Whereas a p-type oxide depicts a high resistance and a n-type oxide a low resistance.

  10. Defect pin behaviour in the DFR

    International Nuclear Information System (INIS)

    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

  11. Defect kinetics in novel detector materials

    CERN Document Server

    MacEvoy, B C

    2000-01-01

    Silicon particle detectors will be used extensively in experiments at the CERN Large Hadron Collider, where unprecedented particle fluences will cause significant atomic displacement damage. We present a model of the evolution of defect concentrations and consequent electrical behaviour in "novel" detector materials with various oxygen and carbon impurity concentrations. The divacancy-oxygen (V/sub 2/O) defect is identified as the cause of changes in device characteristics during /sup 60/Co gamma irradiation. In the case of hadron irradiation changes in detector doping concentration (N/sub eff/) are dominated by cluster defects, in particular the divacancy (V/sub 2/), which exchange charge directly via a non-Shockley-Read- Hall mechanism. The V/sub 2/O defect also contributes to Ne/sub eff/. This defect is more copiously produced during 24 GeV/c proton irradiation than during 1 MeV neutron irradiation on account of the higher vacancy introduction rate, hence the radiation hardness of materials is more sensiti...

  12. Topological defects in open string field theory

    Science.gov (United States)

    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.

  13. Local defect resonance for sensitive non-destructive testing

    Science.gov (United States)

    Adebahr, W.; Solodov, I.; Rahammer, M.; Gulnizkij, N.; Kreutzbruck, M.

    2016-02-01

    Ultrasonic wave-defect interaction is a background of ultrasound activated techniques for imaging and non-destructive testing (NDT) of materials and industrial components. The interaction, primarily, results in acoustic response of a defect which provides attenuation and scattering of ultrasound used as an indicator of defects in conventional ultrasonic NDT. The derivative ultrasonic-induced effects include e.g. nonlinear, thermal, acousto-optic, etc. responses also applied for NDT and defect imaging. These secondary effects are normally relatively inefficient so that the corresponding NDT techniques require an elevated acoustic power and stand out from conventional ultrasonic NDT counterparts for their specific instrumentation particularly adapted to high-power ultrasonic. In this paper, a consistent way to enhance ultrasonic, optical and thermal defect responses and thus to reduce an ultrasonic power required is suggested by using selective ultrasonic activation of defects based on the concept of local defect resonance (LDR). A strong increase in vibration amplitude at LDR enables to reliably detect and visualize the defect as soon as the driving ultrasonic frequency is matched to the LDR frequency. This also provides a high frequency selectivity of the LDR-based imaging, i.e. an opportunity of detecting a certain defect among a multitude of other defects in material. Some examples are shown how to use LDR in non-destructive testing techniques, like vibrometry, ultrasonic thermography and shearography in order to enhance the sensitivity of defect visualization.

  14. Positron annihilation spectroscopy in defects of semiconductors

    International Nuclear Information System (INIS)

    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.)

  15. Perception of risk from automobile safety defects.

    Science.gov (United States)

    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.

  16. Defects in semiconductors

    International Nuclear Information System (INIS)

    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

  17. Wafer plane inspection for advanced reticle defects

    Science.gov (United States)

    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.

  18. Optimized reversible binary-coded decimal adders

    DEFF Research Database (Denmark)

    Thomsen, Michael Kirkedal; Glück, Robert

    2008-01-01

    Abstract Babu and Chowdhury [H.M.H. Babu, A.R. Chowdhury, Design of a compact reversible binary coded decimal adder circuit, Journal of Systems Architecture 52 (5) (2006) 272-282] recently proposed, in this journal, a reversible adder for binary-coded decimals. This paper corrects and optimizes...... their design. The optimized 1-decimal BCD full-adder, a 13 × 13 reversible logic circuit, is faster, and has lower circuit cost and less garbage bits. It can be used to build a fast reversible m-decimal BCD full-adder that has a delay of only m + 17 low-power reversible CMOS gates. For a 32-decimal (128-bit....... Keywords: Reversible logic circuit; Full-adder; Half-adder; Parallel adder; Binary-coded decimal; Application of reversible logic synthesis...

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-05-01

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

  1. Reduction of Defects in Jewelry Manufacturing

    Science.gov (United States)

    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.

  2. Ultrasonic defect detection method for socket welding joint

    International Nuclear Information System (INIS)

    Tominaga, Masaaki; Matsuo, Toshiyuki; Ueno, Akihiro; Watanabe, Kunimichi; Kawamata, Kunio.

    1995-01-01

    The present invention provides a method of detecting defects over a wide range of a socket weld portion of various kinds of pipelines used, for example, in a nuclear power plant. Namely, an inclined probe is disposed to a jig for detecting defects by ultrasonic waves. This is rotated at least by one turn along the peripheral surface of the material to be detected such as weld tube joints. Defects of weld portion of the material can be detected automatically by using ultrasonic waves during the rotation. The inclined probe for detecting defects by ultrasonic waves comprises a transmission portion having a planar transmittance oscillator disposed to a wedge on the transmission side and a receiving portion comprising a planar receiving oscillator disposed to a wedge on the receiving side. With such a constitution, ultrasonic waves are emitted from the transmission portion to the defect detection portion in the welded portion. If a defect is present, defective echo is reflected to the receiving portion disposed ahead of the probe. Since the defective echo changes depending on the height of the detective portion, the estimation of the height of the defect can be facilitated. (I.S.)

  3. Tracking architectural defects in university building in Malaysia

    Directory of Open Access Journals (Sweden)

    Mohd Isa Haryati

    2016-01-01

    Full Text Available Building defects are always the key concern in the construction industry. Defects represent not only a loss to the project but also hamper the smooth operation of a building. Recognising the need to resolve these continuing problems, a research was mooted to track from the study of defects that occurred during the Defects Liability Period in a public university in Malaysia. This paper presents part of the research which investigates what can be learnt from the analysis of architectural defects in these projects. Two research objectives were developed (1 to investigate types of architectural defects that occurred and (2 to analyse the causes of the defects. A mixed methods approach is adopted. Data for the quantitative element of the research was drawn from defects audit records of the project. They were sorted, grouped and transferred into the SPSS software for analysis using the measure of central tendencies and frequency analysis. The findings suggest that with a proper methodology in place, defects can be effectively traced and categorised. This can provide very useful insights to their root cause and how this can be avoided in future projects.

  4. A direct gene transfer strategy via brain internal capsule reverses the biochemical defect in Tay-Sachs disease.

    Science.gov (United States)

    Martino, S; Marconi, P; Tancini, B; Dolcetta, D; De Angelis, M G Cusella; Montanucci, P; Bregola, G; Sandhoff, K; Bordignon, C; Emiliani, C; Manservigi, R; Orlacchio, A

    2005-08-01

    Therapy for neurodegenerative lysosomal Tay-Sachs (TS) disease requires active hexosaminidase (Hex) A production in the central nervous system and an efficient therapeutic approach that can act faster than human disease progression. We combined the efficacy of a non-replicating Herpes simplex vector encoding for the Hex A alpha-subunit (HSV-T0alphaHex) and the anatomic structure of the brain internal capsule to distribute the missing enzyme optimally. With this gene transfer strategy, for the first time, we re-established the Hex A activity and totally removed the GM2 ganglioside storage in both injected and controlateral hemispheres, in the cerebellum and spinal cord of TS animal model in the span of one month's treatment. In our studies, no adverse effects were observed due to the viral vector, injection site or gene expression and on the basis of these results, we feel confident that the same approach could be applied to similar diseases involving an enzyme defect.

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

    International Nuclear Information System (INIS)

    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)

  6. Channeling studies of impurity-defect interactions in silicon

    International Nuclear Information System (INIS)

    Wiggers, L.W.

    1978-01-01

    This thesis deals with the mechanism of defect production and interaction of introduced defects with impurity atoms in silicon single crystals. Defects are created by irradiation with energetic light particles (.2 - 3 MeV H + or He + ions). Mostly simple defects like vacancies and interstitials are produced during bombardment. (Auth.)

  7. Ultrasonic defect characterization using parametric-manifold mapping

    Science.gov (United States)

    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. Cladribine and Fludarabine Nucleotides Induce Distinct Hexamers Defining a Common Mode of Reversible RNR Inhibition.

    Science.gov (United States)

    Wisitpitthaya, Somsinee; Zhao, Yi; Long, Marcus J C; Li, Minxing; Fletcher, Elaine A; Blessing, William A; Weiss, Robert S; Aye, Yimon

    2016-07-15

    The enzyme ribonucleotide reductase (RNR) is a major target of anticancer drugs. Until recently, suicide inactivation in which synthetic substrate analogs (nucleoside diphosphates) irreversibly inactivate the RNR-α2β2 heterodimeric complex was the only clinically proven inhibition pathway. For instance, this mechanism is deployed by the multifactorial anticancer agent gemcitabine diphosphate. Recently reversible targeting of RNR-α-alone coupled with ligand-induced RNR-α-persistent hexamerization has emerged to be of clinical significance. To date, clofarabine nucleotides are the only known example of this mechanism. Herein, chemoenzymatic syntheses of the active forms of two other drugs, phosphorylated cladribine (ClA) and fludarabine (FlU), allow us to establish that reversible inhibition is common to numerous drugs in clinical use. Enzyme inhibition and fluorescence anisotropy assays show that the di- and triphosphates of the two nucleosides function as reversible (i.e., nonmechanism-based) inhibitors of RNR and interact with the catalytic (C site) and the allosteric activity (A site) sites of RNR-α, respectively. Gel filtration, protease digestion, and FRET assays demonstrate that inhibition is coupled with formation of conformationally diverse hexamers. Studies in 293T cells capable of selectively inducing either wild-type or oligomerization-defective mutant RNR-α overexpression delineate the central role of RNR-α oligomerization in drug activity, and highlight a potential resistance mechanism to these drugs. These data set the stage for new interventions targeting RNR oligomeric regulation.

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

    International Nuclear Information System (INIS)

    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

  10. Intracytoplasmic maturation of the human immunodeficiency virus type 1 reverse transcription complexes determines their capacity to integrate into chromatin

    Directory of Open Access Journals (Sweden)

    Kashanchi Fatah

    2006-01-01

    integration into chromatin. Conclusion These results suggest that RTC maturation occurs predominantly in the cytoplasm. Immature RTCs containing RT and incomplete DNA can translocate into the nucleus during mitosis and complete reverse transcription, but are defective for integration.

  11. Agricultural Compounds in Water and Birth Defects.

    Science.gov (United States)

    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.

  12. A novel inspection system for cosmetic defects

    Science.gov (United States)

    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.

  13. ECG-manifest and ECG-silent dipyridamole technetium-99m sestamibi SPET perfusion defects in patients with ischaemic heart disease

    International Nuclear Information System (INIS)

    Galli, M.; Marcassa, C.; Bosimini, E.; Zoccarato, O.; Comazzi, F.; Giannuzzi, P.

    1997-01-01

    To investigate the relationship between ECG changes and perfusion abnormalities, body surface maps were recorded during dipyridamole infusion in 55 subjects (11 normals and 44 patients with ischaemic heart disease) undergoing dipyridamole technetium-99m sestamibi single-photon emission tomography (SPET). All had a normal resting ECG. The extent and severity of the sestamibi defect were quantified. New negative areas in the isointegral maps and rest-dipyridamole map differences >2 SD from normal limits were considered abnormal. After dipyridamole in normals, neither perfusion defects nor ≥1 mm ST segment depression on 12-lead ECG nor new negative areas in isointegral maps occurred. In patients, dipyridamole induced new perfusion defects in 35 (80%) but ST segment depression in only 18 (41%, P<0.001). Of the 35 patients with perfusion defects, 17 (49%, group 1) showed ST segment depression, while the other 18 (51%, group 2) did not. Abnormal body surface maps were found in 100% of group 1 and 88% of group 2 patients (NS). In group 1, the provoked hypoperfusion was of greater extent (P=0.007) and severity (P=0.01) and the onset of map abnormalities was significantly earlier (P<0.001) than in group 2; time to map abnormalities was also significantly shorter than time to ST segment depression (P=0.01). In the 35 patients with complete scintigraphic, body map and angiographic data, the severity of reversible perfusion defect proved to be the strongest correlate of ST segment depression upon logistic regression analysis. Thus, sestamibi SPET abnormalities after dipyridamole are almost always associated with electrical changes on body surface maps, suggesting myocardial ischaemia as their cause. The much less common 12-lead ECG changes are slower to appear and reflect a more severe hypoperfusion. (orig./MG). With 5 figs., 4 tabs

  14. Peculiarities of radiation defect formation and annealing in n-Si due to their interaction with each other and defect clusters

    International Nuclear Information System (INIS)

    Lugakov, P.F.; Lukyanitsa, V.V.

    1984-01-01

    Rearrangement processes proceeding during annealing (T/sub a/ = 50 to 500 0 C) of radiation defects in 60 Co γ-irradiated (T/sub irr/ 0 C) n-Si crystals (rho = 100 to 600 Ωcm) grown by the vacuum float-zone technique are studied. The temperature dependences of the Hall coefficient are measured. The results obtained are interpreted taking into account the interaction during annealing of vacancy-type defects (E-centres, divacancies) with each other and interstitial radiation defects (C/sub i/-C/sub s/ complexes, interstitial carbon C/sub i/). Phosphorus-two vacancies complexes, stable to T/sub a/ >= 500 0 C, are shown to be formed as a result of rearrangements and interaction of E-centres between themselves. The character of interaction of vacancy defects with interstitial ones is found to change significantly in the presence of defect clusters in the bulk of the crystal which are formed under heat treatment (T = 800 0 C, two hours) of the samples preliminary irradiated with fast neutrons (flux PHI/sub n/ = 1x10 14 to 1x10 16 cm -2 ). The peculiarities of radiation defects annealing observed in this case are explained taking into account the influence of defect clusters on the migration processes of mobile defects. Nature of radiation defects being formed at various stages of annealing is discussed. (author)

  15. Pullout Performances of Grouted Rockbolt Systems with Bond Defects

    Science.gov (United States)

    Xu, Chang; Li, Zihan; Wang, Shanyong; Wang, Shuren; Fu, Lei; Tang, Chunan

    2018-03-01

    This paper presents a numerical study on the pullout behaviour of fully grouted rockbolts with bond defects. The cohesive zone model (CZM) is adopted to model the bond-slip behaviour between the rockbolt and grout material. Tensile tests were also conducted to validate the numerical model. The results indicate that the defect length can obviously influence the load and stress distributions along the rockbolt as well as the load-displacement response of the grouted system. Moreover, a plateau in the stress distribution forms due to the bond defect. The linear limit and peak load of the load-displacement response decrease as the defect length increases. A bond defect located closer to the loaded end leads to a longer nonlinear stage in the load-displacement response. However, the peak loads measured from the specimens made with various defect locations are almost approximately the same. The peak load for a specimen with the defects equally spaced along the bolt is higher than that for a specimen with defects concentrated in a certain zone, even with the same total defect length. Therefore, the dispersed pattern of bond defects would be much safer than the concentrated pattern. For the specimen with dispersed defects, the peak load increases with an increase in the defect spacing, even if the total defect length is the same. The peak load for a grouted rockbolt system with defects increases with an increases in the bolt diameter. This work leads to a better understanding of the load transfer mechanism for grouted rockbolt systems with bond defects, and paves the way towards developing a general evaluation method for damaged rockbolt grouted systems.

  16. Defect detection of wall thinning defect in pipes using lock-in photo-infrared thermography technique

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Su Ok; Park, Jong Hyun; Choi, Tae Ho; Jung, Hyun Chul; Kim, Kyoung Suk [Chosun Univ., Gwangju (Korea, Republic of)

    2008-07-01

    Piping in the Nuclear Power plants (NPP) are mostly consisted of carbon steel pipe. The wall thinning defect is mainly occurred by the affect of the Flow Accelerated Corrosion (FAC) of fluid which flows in carbon steel pipes. This type of defect becomes the cause of damage or destruction of piping. Therefore, it is very important to measure defect which is existed not only on the welding partbut also on the whole field of pipe. Over the years, Infrared Thermography (IRT) has been used as a non destructive testing methods of the various kinds of materials. This technique has many merits and applied to the industrial field but has limitation to the materials. Therefore, this method was combined with lock-in technique. So IRT detection resolution has been progressively improved using lock-in technique. In this paper, the quantitative analysis results of the location and the size of wall thinning defect that is artificially processed inside the carbon steel pipe by using IRT are obtained.

  17. What do reversible programs compute?

    DEFF Research Database (Denmark)

    Axelsen, Holger Bock; Glück, Robert

    2011-01-01

    Reversible computing is the study of computation models that exhibit both forward and backward determinism. Understanding the fundamental properties of such models is not only relevant for reversible programming, but has also been found important in other fields, e.g., bidirectional model...... transformation, program transformations such as inversion, and general static prediction of program properties. Historically, work on reversible computing has focussed on reversible simulations of irreversible computations. Here, we take the viewpoint that the property of reversibility itself should...... are not strictly classically universal, but that they support another notion of universality; we call this RTM-universality. Thus, even though the RTMs are sub-universal in the classical sense, they are powerful enough as to include a self-interpreter. Lifting this to other computation models, we propose r...

  18. Fundamentals of reversible flowchart languages

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2016-01-01

    Abstract This paper presents the fundamentals of reversible flowcharts. They are intended to naturally represent the structure and control flow of reversible (imperative) programming languages in a simple computation model, in the same way classical flowcharts do for conventional languages......, structured reversible flowcharts are as expressive as unstructured ones, as shown by a reversible version of the classic Structured Program Theorem. We illustrate how reversible flowcharts can be concretized with two example programming languages, complete with syntax and semantics: a low-level unstructured...... language and a high-level structured language. We introduce concrete tools such as program inverters and translators for both languages, which follow the structure suggested by the flowchart model. To further illustrate the different concepts and tools brought together in this paper, we present two major...

  19. On the connection of the ESR characteristics of zircons with the degree of their defectiveness

    International Nuclear Information System (INIS)

    Matyash, I.V.; Brik, A.E.; Derski, L.S.; Larikov, A.L.; Ponomarenko, A.N.

    1989-01-01

    The dynamic characteristics of the electron-hole centres (EHC) in zircons with various degree of defectiveness have been studied. Crystalline and amorphous regions are typical of different sets of EHC, having essentially different relaxation characteristics. Lack of cross-relaxation between these centres shows that they are localized in different parts of the crystal. The influence of autoirradiation and of corresponding defectiveness of the matrix upon the intensity of the EHC signals (V i ) has been studied. In the specimens of high crystallinity V i increases as the content of radioactive elements and defectiveness increases. In the essentially metamict specimens the situation reverses. Interpretation of this effect is given considering the dose dependence of the ESR signals and the ratio of the crystal and metamict volumes in the studied object. The transformations of the EHC set is traced along the amorphization of the zircon matrix due to the autoirradiation. ESR signals corresponding to different phases in zircon have been recorded. The correlation of the zircon grain size and the static magnetic susceptibility with V i have been studied. In the specimens of high crystallinity such correlation is absent and in metamict specimens the intensities V i decrease as the grain sizes decrease. The interpretation of this fact is proposed. It has been shown that the ESR studies reflect the processes of income and migration of the impurity elements in zircons and the ways of the zircon crystal matrix decay in a geological time scale. The factors controlling such a decay have been found. (author)

  20. Disc defect classification for optical disc drives

    NARCIS (Netherlands)

    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

  1. Defect grating modes as superimposed grating states

    NARCIS (Netherlands)

    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

  2. Magnetic reversals from planetary dynamo waves

    DEFF Research Database (Denmark)

    Sheyko, Andrey; Finlay, Chris; Jackson, Andrew

    2016-01-01

    A striking feature of many natural dynamos is their ability to undergo polarity reversals. The best documented example is Earth's magnetic field, which has reversed hundreds of times during its history. The origin of geomagnetic polarity reversals lies in a magnetohydrodynamic process that takes ...... to kinematic dynamo waves. Because our results are relevant in a regime of low viscosity and high magnetic diffusivity, and with geophysically appropriate boundary conditions, this form of dynamo wave may also be involved in geomagnetic reversals.......A striking feature of many natural dynamos is their ability to undergo polarity reversals. The best documented example is Earth's magnetic field, which has reversed hundreds of times during its history. The origin of geomagnetic polarity reversals lies in a magnetohydrodynamic process that takes...... place in Earth's core, but the precise mechanism is debated. The majority of numerical geodynamo simulations that exhibit reversals operate in a regime in which the viscosity of the fluid remains important, and in which the dynamo mechanism primarily involves stretching and twisting of field lines...

  3. Eddy current inspection of weld defects in tubing

    Science.gov (United States)

    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.

  4. Infrared computations of defect Schur indices

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. Holographic entanglement entropy of surface defects

    International Nuclear Information System (INIS)

    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.

  6. Holographic entanglement entropy of surface defects

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. Phosphorous–vacancy–oxygen defects in silicon

    KAUST Repository

    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.

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

    Science.gov (United States)

    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.

  9. Solving a Closed-Loop Location-Inventory-Routing Problem with Mixed Quality Defects Returns in E-Commerce by Hybrid Ant Colony Optimization Algorithm

    Directory of Open Access Journals (Sweden)

    Shuai Deng

    2016-01-01

    Full Text Available This paper presents a closed-loop location-inventory-routing problem model considering both quality defect returns and nondefect returns in e-commerce supply chain system. The objective is to minimize the total cost produced in both forward and reverse logistics networks. We propose a combined optimization algorithm named hybrid ant colony optimization algorithm (HACO to address this model that is an NP-hard problem. Our experimental results show that the proposed HACO is considerably efficient and effective in solving this model.

  10. Transgene silencing of the Hutchinson-Gilford progeria syndrome mutation results in a reversible bone phenotype, whereas resveratrol treatment does not show overall beneficial effects

    DEFF Research Database (Denmark)

    Strandgren, Charlotte; Nasser, Hasina Abdul; McKenna, Tomás

    2015-01-01

    model to study the possibility of recovering from HGPS bone disease upon silencing of the HGPS mutation, and the potential benefits from treatment with resveratrol. We show that complete silencing of the transgenic expression of progerin normalized bone morphology and mineralization already after 7...... weeks. The improvements included lower frequencies of rib fractures and callus formation, an increased number of osteocytes in remodeled bone, and normalized dentinogenesis. The beneficial effects from resveratrol treatment were less significant and to a large extent similar to mice treated with sucrose...... alone. However, the reversal of the dental phenotype of overgrown and laterally displaced lower incisors in HGPS mice could be attributed to resveratrol. Our results indicate that the HGPS bone defects were reversible upon suppressed transgenic expression and suggest that treatments targeting aberrant...

  11. Lumber defect detection by ultrasonics

    Science.gov (United States)

    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.

  12. Angiographic differentiation of type of ventricular septal defects

    International Nuclear Information System (INIS)

    Cheon, Mal Soon; Park, Hee Young; Kim, Yang Sook

    1989-01-01

    Defects of the ventricular septum are the commonest type of congenital cardiac malformations. A classification with axial angiography of the subtypes of ventricular septal defects is proposed on the study of 126 patients with defects of the ventricular septum. The results were as follows: 1. The incidence of the ventricular septal defects was 39.6% of congenital heart malformation. 2. The sex distribution of cases were 70 males and 56 females, the age ranged from 13 months to 26 years. 3. Angiographic features seen by axial angiography were as follows: a. Perimembranous defects as seen on long axial view of left ventriculogram were in continuity wity aortic valve. The relation of the defect to the tricuspid valve allows distinction of the extension of the preimembranous defect toward inlet, trabecular, or infundibular zones. This relation was determined angiographically, using the course of the contrast medium from the left ventricle through the ventricular septal defect, opacifying the right ventricle. In inlet excavation, the shunted blood opacified the recess between septal leaflet of tricuspid valve and interventricular septum in early phase, in infundibular excavation, opacified the recess between anterior leaflet of tricuspid valve and anterior free wall of right ventricle and in trabecular excavation, the shunted blood traversed anterior portion of tricuspid valve ring, opacified trabecular portion of right ventricle. b. Muscular defects were separated from the semilunar and atrioventricular valves. c, Subarterial defects were related to both semilunar valves, and they were best demonstrated on the elongated right anterior oblique view of the left ventriculogram. d. Total infundibular defects were profiled in right anterior oblique 30 and long axial view, subaortic in location in both views

  13. Defect Chemistry of Oxides for Energy Applications.

    Science.gov (United States)

    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.

  14. Defect assessment procedures at high temperature

    International Nuclear Information System (INIS)

    Ainsworth, R.A.

    1991-01-01

    A comprehensive assessment procedure for the high-temperature response of structures is being produced. The procedure is referred to as R5 and is written as a series of step-by-step instructions in a number of volumes. This paper considers in detail those parts of R5 which address the behaviour of defects. The defect assessment procedures may be applied to defects found in service, postulated defects, or defects formed during operation as a result of creep-fatigue loading. In the last case, a method is described for deducing from endurance data the number of cycles to initiate a crack of a specified size. Under steady loading, the creep crack tip parameter C * is used to assess crack growth. Under cyclic loading, the creep crack growth during dwell periods is stiell governed by C * but crack growth due to cyclic excursions must also be included. This cyclic crack growth is described by an effective stress intensity factor range. A feature of the R5 defect assessment procedures in that they are based on simplified methods and approximate reference stress methods are described which enable C * in a component to be evaluated. It is shown by comparison with theoretical calculations and experimental data that reliable estimates of C * and the associated crack growth are obtained provided realistic creep strain rate date are used in the reference stress approximation. (orig./HP)

  15. Restoration of Motor Defects Caused by Loss of Drosophila TDP-43 by Expression of the Voltage-Gated Calcium Channel, Cacophony, in Central Neurons.

    Science.gov (United States)

    Lembke, Kayly M; Scudder, Charles; Morton, David B

    2017-09-27

    expression levels, but the specific defects caused by TDP-43 loss of function have not been described in detail. A Drosophila loss-of-function model displays pronounced locomotion defects that can be reversed by restoring the expression levels of a voltage-gated calcium channel, cacophony. We show these defects can be rescued by expression of cacophony in motor neurons and by expression in two pairs of neurons in the brain. These data suggest that loss of TDP-43 can disrupt the central circuitry of the CNS, opening up identification of alternative therapeutic targets for TDP-43 proteinopathies. Copyright © 2017 the authors 0270-6474/17/379486-12$15.00/0.

  16. Endotracheal tube defects: Hidden causes of airway obstruction

    Directory of Open Access Journals (Sweden)

    Sofi Khalid

    2010-01-01

    Full Text Available Manufacturing defects of endotracheal tube (ETT are still encountered in anesthesia practice. Many such defects go unnoticed during routine inspection prior to their use. Such defects in ETT may lead to partial or complete airway obstruction in an intubated patient. We report a case of partial airway obstruction with a prepacked, single use, uncuffed ETT due to a manufacturing defect in the form of a plastic meniscus at the distal end of the tube. This case report highlights the significance of standard monitoring of ventilation and the role of a vigilant clinician in detecting such defects in avoiding critical events as can arise from the use of such defective ETTs. It also emphasizes the need for double checking ETTs prior to their use.

  17. Teratology: from science to birth defects prevention.

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  19. Vibration of carbon nanotubes with defects: order reduction methods

    Science.gov (United States)

    Hudson, Robert B.; Sinha, Alok

    2018-03-01

    Order reduction methods are widely used to reduce computational effort when calculating the impact of defects on the vibrational properties of nearly periodic structures in engineering applications, such as a gas-turbine bladed disc. However, despite obvious similarities these techniques have not yet been adapted for use in analysing atomic structures with inevitable defects. Two order reduction techniques, modal domain analysis and modified modal domain analysis, are successfully used in this paper to examine the changes in vibrational frequencies, mode shapes and mode localization caused by defects in carbon nanotubes. The defects considered are isotope defects and Stone-Wales defects, though the methods described can be extended to other defects.

  20. A functional language for describing reversible logic

    DEFF Research Database (Denmark)

    Thomsen, Michael Kirkedal

    2012-01-01

    Reversible logic is a computational model where all gates are logically reversible and combined in circuits such that no values are lost or duplicated. This paper presents a novel functional language that is designed to describe only reversible logic circuits. The language includes high....... Reversibility of descriptions is guaranteed with a type system based on linear types. The language is applied to three examples of reversible computations (ALU, linear cosine transformation, and binary adder). The paper also outlines a design flow that ensures garbage- free translation to reversible logic...... circuits. The flow relies on a reversible combinator language as an intermediate language....

  1. Geomagnetic Reversals during the Phanerozoic.

    Science.gov (United States)

    McElhinny, M W

    1971-04-09

    An antalysis of worldwide paleomagnetic measurements suggests a periodicity of 350 x 10(6) years in the polarity of the geomagnetic field. During the Mesozoic it is predominantly normal, whereas during the Upper Paleozoic it is predominantly reversed. Although geomagnetic reversals occur at different rates throughout the Phanerozoic, there appeaars to be no clear correlation between biological evolutionary rates and reversal frequency.

  2. Nanoscale Phase Stability Reversal During the Nucleation and Growth of Titanium Oxide Minerals

    Science.gov (United States)

    Hummmer, D. R.; Heaney, P. J.; Kubicki, J. D.; Kent, P. R.; Post, J. E.

    2008-12-01

    Fine-grained titanium oxide minerals are important in soils, where they affect a variety of geochemical processes. They are also industrially important as catalysts, pigments, food additives, and dielectrics. Recent research has indicated an apparent reversal of thermodynamic stability between TiO2 phases at the nanoscale thought to be caused by an increased contribution of surface energy to the total free energy. Time-resolved X-ray diffraction (XRD) experiments in which titanium oxides crystallize from aqueous TiCl4 solutions confirm that anatase, a metastable phase, is always the first phase to nucleate under our range of initial conditions. Rutile peaks are observed only minutes after the first appearance of anatase, after which anatase abundance slowly decreases while rutile continues to form. Whole pattern refinement of diffraction data reveals that lattice constants of both phases increase throughout the crystallization process. In addition, transmission electron microscope (TEM) observations and kinetic modeling indicate that anatase does not undergo a solid-state transformation to the rutile structure as once thought. Instead, anatase appears to re-dissolve and then feed the growth of already nucleated rutile nanocrystals. Density functional theory (DFT) calculations were employed to model 1, 2, and 3 nm particles of both mineral phases. The total surface energies calculated from these models did yield lower values for anatase than for rutile by 8-13 kJ/mol depending on particle size, indicating that surface free energy is sufficient to account for stability reversal. However, these whole-particle surface energies were much higher than the sum of energies of each particle's constituent crystallographic surfaces. We attribute the excess energy to defects associated with the edges and corners of nanoparticles, which are not present on a 2-D periodic surface. This previously unreported edge and corner energy may play a dominant role in the stability reversal

  3. Defect branes as Alice strings

    International Nuclear Information System (INIS)

    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.

  4. Defect branes as Alice strings

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. Positron annihilation spectroscopy in defects of semiconductors

    CERN Document Server

    Fujinami, M

    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 sup 1 sup 8 cm sup - sup 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 sup 1 sup 5 cm sup - sup 2) silicon and oxygen-implanted (180 keV, 2x10 sup 1 sup 5 cm sup - sup 2) silicon are stated. On the oxygen-implanted silicon, the main product was V2 after implantation, V sub 6 O sub 2 at 600degC and V sub 1 sub 0 O sub 6 at 800degC. (S.Y.)

  6. Resveratrol reverses morphine-induced neuroinflammation in morphine-tolerant rats by reversal HDAC1 expression

    Directory of Open Access Journals (Sweden)

    Ru-Yin Tsai

    2016-06-01

    Conclusion: Resveratrol restores the antinociceptive effect of morphine by reversing morphine infusion-induced spinal cord neuroinflammation and increase in TNFR1 expression. The reversal of the morphine-induced increase in TNFR1 expression by resveratrol is partially due to reversal of the morphine infusion-induced increase in HDAC1 expression. Resveratrol pretreatment can be used as an adjuvant in clinical pain management for patients who need long-term morphine treatment or with neuropathic pain.

  7. Theory of Defects in Semiconductors

    CERN Document Server

    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.

  8. Defect CFTs and holographic multiverse

    International Nuclear Information System (INIS)

    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

  9. A novel mutation of the adrenocorticotropin receptor (ACTH-R) gene in a family with the syndrome of isolated glucocorticoid deficiency, but no ACTH-R abnormalities in two families with the triple A syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Tsigos, C.; Arai, K.; Latronico, A.C. [National Inst. of Child Health and Human Development, Bethesda, MD (United States)]|[Temple Univ. School of Medicine, Philadelphia, PA (United States)]|[Children`s Hospital of New Jersey, Newark, NJ (United States)] [and others

    1995-07-01

    Isolated glucocorticoid deficiency (IGD) is an autosomal recessive disorder characterized by primary adrenocortical insufficiency, usually without mineralocorticoid deficiency. Occasionally, the disorder is associated with alacrima and achalasia of the esophagus (triple A syndrome), suggesting potential heterogeneity in its etiology. Mutations in the ACTH receptor gene have been reported in several families with IGD. We have amplified and directly sequenced the entire intronless ACTH receptor gene in 1 other family with IGD and 2 famlies with triple A syndrome. The proband with IGD was a homozygote for an A {r_arrow}G substitution, changing tyrosine 254 to cysteine in the third extracellular loop of the receptor protein, probably interfering with ligand binding. Both of her parents were heterozygotes for this mutation, which was not detected in 100 normal alleles. No mutations were identified in the entire coding area of the ACTH receptor in the 2 families with triple A syndrome, supporting the idea of a developmental or postreceptor defect in this syndrome. 19 refs., 1 fig.

  10. Actinic inspection of multilayer defects on EUV masks

    International Nuclear Information System (INIS)

    Barty, A; Liu, Y; Gullikson, E; Taylor, J S; Wood, O

    2005-01-01

    The production of defect-free mask blanks, and the development of techniques for inspecting and qualifying EUV mask blanks, remains a key challenge for EUV lithography. In order to ensure a reliable supply of defect-free mask blanks, it is necessary to develop techniques to reliably and accurately detect defects on un-patterned mask blanks. These inspection tools must be able to accurately detect all critical defects whilst simultaneously having the minimum possible false-positive detection rate. There continues to be improvement in high-speed non-actinic mask blank inspection tools, and it is anticipated that these tools can and will be used by industry to qualify EUV mask blanks. However, the outstanding question remains one of validating that non-actinic inspection techniques are capable of detecting all printable EUV defects. To qualify the performance of non-actinic inspection tools, a unique dual-mode EUV mask inspection system has been installed at the Advanced Light Source (ALS) synchrotron at Lawrence Berkeley National Laboratory. In high-speed inspection mode, whole mask blanks are scanned for defects using 13.5-nm wavelength light to identify and map all locations on the mask that scatter a significant amount of EUV light. In imaging, or defect review mode, a zone plate is placed in the reflected beam path to image a region of interest onto a CCD detector with an effective resolution on the mask of 100-nm or better. Combining the capabilities of the two inspection tools into one system provides the unique capability to determine the coordinates of native defects that can be used to compare actinic defect inspection with visible light defect inspection tools under commercial development, and to provide data for comparing scattering models for EUV mask defects

  11. Principles of a reversible programming language

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2008-01-01

    The principles of reversible programming languages are explicated and illustrated with reference to the design of a high-level imperative language, Janus. The fundamental properties for such languages include backward as well as forward determinism and reversible updates of data. The unique design...... languages, and demonstrate this for Janus. We show the practicality of the language by implementation of a reversible fast Fourier transform. Our results indicate that the reversible programming paradigm has fundamental properties that are relevant to many different areas of computer science....... features of the language include explicit post-condition assertions, direct access to an inverse semantics and the possibility of clean (i.e., garbage-free) computation of injective functions. We suggest the clean simulation of reversible Turing machines as a criterion for computing strength of reversible...

  12. Defect Depth Measurement of Straight Pipe Specimen Using Shearography

    International Nuclear Information System (INIS)

    Chang, Ho Seob; Kim, Kyung Suk

    2012-01-01

    In the nuclear industry, wall thinning defect of straight pipe occur the enormous loss in life evaluation and safety evaluation. To use non-destructive technique, we measure deformation, vibration, defect evaluation. But, this techniques are a weak that is the measurement of the wide area is difficult and the time is caught long. In the secondary side of nuclear power plants mostly used steel pipe, artificiality wall thinning defect make in the side and different thickness make to the each other, wall thinning defect part of deformation measure by using shearography. In addition, optical measurement through deformation, vibration, defect evaluation evaluate pipe and thickness defects of pressure vessel is to evaluate quantitatively. By shearography interferometry to measure the pipe's internal wall thinning defect and the variation of pressure use the proposed technique, the quantitative defect is to evaluate the thickness of the surplus. The amount of deformation use thickness of surplus prediction of the actual thickness defect and approximately 7 percent error by ensure reliability. According to pressure the amount of deformation and the thickness of the surplus through DB construction, nuclear power plant pipe use wall thinning part soundness evaluation. In this study, pressure vessel of thickness defect measure proposed nuclear pipe of wall thinning defect prediction and integrity assessment technology development. As a basic research defected theory and experiment, pressure vessel of advanced stability and soundness and maintainability is expected to contribute foundation establishment

  13. Ab initio study of point defects in magnesium oxide

    International Nuclear Information System (INIS)

    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

  14. Nanoscale interfacial defect shedding in a growing nematic droplet.

    Science.gov (United States)

    Gurevich, Sebastian; Provatas, Nikolas; Rey, Alejandro

    2017-08-01

    Interfacial defect shedding is the most recent known mechanism for defect formation in a thermally driven isotropic-to-nematic phase transition. It manifests in nematic-isotropic interfaces going through an anchoring switch. Numerical computations in planar geometry established that a growing nematic droplet can undergo interfacial defect shedding, nucleating interfacial defect structures that shed into the bulk as +1/2 point defects. By extending the study of interfacial defect shedding in a growing nematic droplet to larger length and time scales, and to three dimensions, we unveil an oscillatory growth mode involving shape and anchoring transitions that results in a controllable regular distributions of point defects in planar geometry, and complex structures of disclination lines in three dimensions.

  15. Reversible and irreversible wrinkling in tube hydroforming process

    Science.gov (United States)

    El-Aty, Ali Abd; Ahmed, Tauseef; Farooq, Ahmed

    2017-07-01

    The aim of this research is to analyzeandoptimize the hydroforming process parameters in order to achieve a sound bulged tube without failure. Theoretical constitutive model is formulated to develop a working diagram including process window, which represents the optimize region to carry out the hydroforming process and predict the type of tube failure during the process accurately. The model is applied into different bulging ratios for low carbon steel (C1010). From this study, it is concluded that the tubes with bulging ratios up to 50% and 70% are successfully formed without defects. The tubes with bulging ratio of 90% are successfully formed by hydroforming with optimized the loading path (axial feed versus internal pressure) within the process window. The working diagram is modified due to different types of formation of wrinkling during the hydroforming process. The formation of wrinkles with increasing axial feed can be useful in terms of the achievement of higher bulging ratio and/or less thinning and this type of wrinkles can be overcome through the internal pressure in the later stage of the hydroforming process. On the other hand, the formation of wrinkles may be harmful, if it cannot be reversed.

  16. Magnetization reversal in nucleation controlled magnets. I. Theory

    International Nuclear Information System (INIS)

    Ramesh, R.; Srikrishna, K.

    1988-01-01

    A statistical model, based upon earlier models of Brown [J. Appl. Phys. 33, 3022 (1962)] and McIntyre [J. Phys. D 3, 1430 (1970)] has been developed to examine the magnetization reversal of domain-wall nucleation controlled permanent magnets such as sintered Fe-Nd-B and SmCo 5 . Using a Poisson distribution of the defects on the surface of the grains, a ''weakest link statistics'' type model has been developed. The model has been used to calculate hysteresis loops for sintered Fe-Nd-B-type polycrystalline magnets. It is shown that the intrinsic coercivity measured for a bulk magnet should vary inversely as the logarithm of the surface area of the grain. The effect of demagnetizing field has been incorporated by a mean-field-type approximation, to calculate the overall nucleation field from the intrinsic coercivity. The hysteresis loops theoretically calculated are in excellent agreement with the overall form of those experimentally determined for similar nucleation controlled magnets. The model also predicts that for an inhomogeneous grain size distribution, such as a bimodal distribution, kinks will be observed in the second quadrant of the hysteresis loops

  17. ‘Picking People to Hate’: Reversible reversals in stand-up comedy

    DEFF Research Database (Denmark)

    Keisalo, Marianna Päivikki

    2017-01-01

    Generally speaking, ritual reversals mean switching to the opposite of what is considered ‘the normal order’. Such reversals can occur, for example, in terms of social hierarchies in rites of passage, in action in carnival, or in the framing of action as ritual or performance. For comedic figures...... cultural grounds and show how the study of comedic performance can offer insights into the semiotics of performance more broadly....

  18. Defective Reduction in Frozen Pie Manufacturing Process

    Science.gov (United States)

    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%.

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

    Science.gov (United States)

    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-...

  20. Periodicity and Immortality in Reversible Computing

    OpenAIRE

    Kari , Jarkko; Ollinger , Nicolas

    2008-01-01

    Additional material available on the web at http://www.lif.univ-mrs.fr/~nollinge/rec/gnirut/; We investigate the decidability of the periodicity and the immortality problems in three models of reversible computation: reversible counter machines, reversible Turing machines and reversible one-dimensional cellular automata. Immortality and periodicity are properties that describe the behavior of the model starting from arbitrary initial configurations: immortality is the property of having at le...

  1. Reduction in Defect Content in ODS Alloys

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. How decision reversibility affects motivation.

    Science.gov (United States)

    Bullens, Lottie; van Harreveld, Frenk; Förster, Jens; Higgins, Tory E

    2014-04-01

    The present research examined how decision reversibility can affect motivation. On the basis of extant findings, it was suggested that 1 way it could affect motivation would be to strengthen different regulatory foci, with reversible decision making, compared to irreversible decision making, strengthening prevention-related motivation relatively more than promotion-related motivation. If so, then decision reversibility should have effects associated with the relative differences between prevention and promotion motivation. In 5 studies, we manipulated the reversibility of a decision and used different indicators of regulatory focus motivation to test these predictions. Specifically, Study 1 tested for differences in participants' preference for approach versus avoidance strategies toward a desired end state. In Study 2, we used speed and accuracy performance as indicators of participants' regulatory motivation, and in Study 3, we measured global versus local reaction time performance. In Study 4, we approached the research question in a different way, making use of the value-from-fit hypothesis (Higgins, 2000, 2002). We tested whether a fit between chronic regulatory focus and focus induced by the reversibility of the decision increased participants' subjective positive feelings about the decision outcome. Finally, in Study 5, we tested whether regulatory motivation, induced by decision reversibility, also influenced participants' preference in specific product features. The results generally support our hypothesis showing that, compared to irreversible decisions, reversible decisions strengthen a prevention focus more than a promotion focus. Implications for research on decision making are discussed.

  3. Phonons, defects and optical damage in crystalline acetanilide

    Science.gov (United States)

    Kosic, Thomas J.; Hill, Jeffrey R.; Dlott, Dana D.

    1986-04-01

    Intense picosecond pulses cause accumulated optical damage in acetanilide crystals at low temperature. Catastrophic damage to the irradiated volume occurs after an incubation period where defects accumulate. The optical damage is monitored with subanosecond time resolution. The generation of defects is studied with damage-detected picosecond spectroscopy. The accumulation of defects is studied by time-resolved coherent Raman scattering, which is used to measure optical phonon scattering from the accumulating defects.

  4. Congenital heart defects and extracardiac malformations.

    Science.gov (United States)

    Rosa, Rosana Cardoso M; Rosa, Rafael Fabiano M; Zen, Paulo Ricardo G; Paskulin, Giorgio Adriano

    2013-06-01

    To review the association between congenital heart defects and extracardiac malformations. Scientific articles were searched in the Medline, Lilacs, and SciELO databases, using the descriptors "congenital heart disease," "congenital heart defects," "congenital cardiac malformations," "extracardiac defects," and "extracardiac malformations." All case series that specifically explored the association between congenital heart defects and extracardiac malformations were included. Congenital heart diseases are responsible for about 40% of birth defects, being one of the most common and severe malformations. Extracardiac malformations are observed in 7 to 50% of the patients with congenital heart disease, bringing a greater risk of comorbidity and mortality and increasing the risks related to heart surgery. Different studies have attempted to assess the presence of extracardiac abnormalities in patients with congenital heart disease. Among the changes described, those of the urinary tract are more often reported. However, no study has evaluated all patients in the same way. Extracardiac abnormalities are frequent among patients with congenital heart disease, and patients with these alterations may present an increased risk of morbimortality. Therefore, some authors have been discussing the importance and cost-effectiveness of screening these children for other malformations by complementary exams.

  5. The Neural Retina in Retinopathy of Prematurity

    Science.gov (United States)

    Hansen, Ronald M.; Moskowitz, Anne; Akula, James D.; Fulton, Anne B.

    2016-01-01

    Retinopathy of prematurity (ROP) is a neurovascular disease that affects prematurely born infants and is known to have significant long term effects on vision. We conducted the studies described herein not only to learn more about vision but also about the pathogenesis of ROP. The coincidence of ROP onset and rapid developmental elongation of the rod photoreceptor outer segments motivated us to consider the role of the rods in this disease. We used noninvasive electroretinographic (ERG), psychophysical, and retinal imaging procedures to study the function and structure of the neurosensory retina. Rod photoreceptor and post-receptor responses are significantly altered years after the preterm days during which ROP is an active disease. The alterations include persistent rod dysfunction, and evidence of compensatory remodeling of the post-receptor retina is found in ERG responses to full-field stimuli and in psychophysical thresholds that probe small retinal regions. In the central retina, both Mild and Severe ROP delay maturation of parafoveal scotopic thresholds and are associated with attenuation of cone mediated multifocal ERG responses, significant thickening of post-receptor retinal laminae, and dysmorphic cone photoreceptors. These results have implications for vision and control of eye growth and refractive development and suggest future research directions. These results also lead to a proposal for noninvasive management using light that may add to the currently invasive therapeutic armamentarium against ROP. PMID:27671171

  6. MODELS OF PROJECT REVERSE ENGINEERING

    Directory of Open Access Journals (Sweden)

    Віктор Володимирович ІВАНОВ

    2017-03-01

    Full Text Available Reverse engineering decided important scientific and technical problems of increasing the cost of the existing technical product by transforming it into a product with other features or design. Search ideas of the new application of existing products on the base of heuristic analysis were created. The concept of reverse engineering and its division into three types: conceptual, aggregate and complete was expanded. The use of heuristic methods for reverse engineering concept was showed. The modification model of Reverse engineering based on the model of РМВОК was developed. Our model includes two new phases: identification and transformation. At the identification phase, technical control is made. At the transformation phase, search heuristic idea of the new applied existing technical product was made. The model of execution phase that included heuristic methods, metrological equipment, and CAD/CAM/CAE program complex was created. The model that connected economic indicators of reverse engineering project was developed.

  7. Micro-bridge defects: characterization and root cause analysis

    Science.gov (United States)

    Santoro, Gaetano; Van den Heuvel, Dieter; Braggin, Jennifer; Rosslee, Craig; Leray, Philippe J.; Cheng, Shaunee; Jehoul, Christiane; Schreutelkamp, Robert; Hillel, Noam

    2010-03-01

    Defect review of advanced lithography processes is becoming more and more challenging as feature sizes decrease. Previous studies using a defect review SEM on immersion lithography generated wafers have resulted in a defect classification scheme which, among others, includes a category for micro-bridges. Micro-bridges are small connections between two adjacent lines in photo-resist and are considered device killing defects. Micro-bridge rates also tend to increase as feature sizes decrease, making them even more important for the next technology nodes. Especially because micro-bridge defects can originate from different root causes, the need to further refine and split up the classification of this type of defect into sub groups may become a necessity. This paper focuses on finding the correlation of the different types of micro-bridge defects to a particular root cause based on a full characterization and root cause analysis of this class of defects, by using advanced SEM review capabilities like high quality imaging in very low FOV, Multi Perspective SEM Imaging (MPSI), tilted column and rotated stage (Tilt&Rotation) imaging and Focused Ion Beam (FIB) cross sectioning. Immersion lithography material has been mainly used to generate the set of data presented in this work even though, in the last part of the results, some EUV lithography data will be presented as part of the continuing effort to extend the micro-bridge defect characterization to the EUV technology on 40 nm technology node and beyond.

  8. Mass defect effects in atomic clocks

    Science.gov (United States)

    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.

  9. Tibial and fibular developmental fields defects

    International Nuclear Information System (INIS)

    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.)

  10. EUV mask defect inspection and defect review strategies for EUV pilot line and high volume manufacturing

    Science.gov (United States)

    Chan, Y. David; Rastegar, Abbas; Yun, Henry; Putna, E. Steve; Wurm, Stefan

    2010-04-01

    Reducing mask blank and patterned mask defects is the number one challenge for extreme ultraviolet lithography. If the industry succeeds in reducing mask blank defects at the required rate of 10X every year for the next 2-3 years to meet high volume manufacturing defect requirements, new inspection and review tool capabilities will soon be needed to support this goal. This paper outlines the defect inspection and review tool technical requirements and suggests development plans to achieve pilot line readiness in 2011/12 and high volume manufacturing readiness in 2013. The technical specifications, tooling scenarios, and development plans were produced by a SEMATECH-led technical working group with broad industry participation from material suppliers, tool suppliers, mask houses, integrated device manufacturers, and consortia. The paper summarizes this technical working group's assessment of existing blank and mask inspection/review infrastructure capabilities to support pilot line introduction and outlines infrastructure development requirements and tooling strategies to support high volume manufacturing.

  11. Logistic planning and control of reworking perishable production defectives

    NARCIS (Netherlands)

    R.H. Teunter (Ruud); S.D.P. Flapper

    2001-01-01

    textabstractWe consider a production line that is dedicated to a single product. Produced lots may be non-defective, reworkable defective, or non-reworkable defective. The production line switches between production and rework. After producing a fixed number (N) of lots, all reworkable defective

  12. Defect CFTs and holographic multiverse

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Oxygen defect processes in silicon and silicon germanium

    KAUST Repository

    Chroneos, A.

    2015-06-18

    Silicon and silicon germanium are the archetypical elemental and alloy semiconductor materials for nanoelectronic, sensor, and photovoltaic applications. The investigation of radiation induced defects involving oxygen, carbon, and intrinsic defects is important for the improvement of devices as these defects can have a deleterious impact on the properties of silicon and silicon germanium. In the present review, we mainly focus on oxygen-related defects and the impact of isovalent doping on their properties in silicon and silicon germanium. The efficacy of the isovalent doping strategies to constrain the oxygen-related defects is discussed in view of recent infrared spectroscopy and density functional theory studies.

  14. Defect-engineered graphene chemical sensors with ultrahigh sensitivity.

    Science.gov (United States)

    Lee, Geonyeop; Yang, Gwangseok; Cho, Ara; Han, Jeong Woo; Kim, Jihyun

    2016-05-25

    We report defect-engineered graphene chemical sensors with ultrahigh sensitivity (e.g., 33% improvement in NO2 sensing and 614% improvement in NH3 sensing). A conventional reactive ion etching system was used to introduce the defects in a controlled manner. The sensitivity of graphene-based chemical sensors increased with increasing defect density until the vacancy-dominant region was reached. In addition, the mechanism of gas sensing was systematically investigated via experiments and density functional theory calculations, which indicated that the vacancy defect is a major contributing factor to the enhanced sensitivity. This study revealed that defect engineering in graphene has significant potential for fabricating ultra-sensitive graphene chemical sensors.

  15. Oxygen defect processes in silicon and silicon germanium

    KAUST Repository

    Chroneos, A.; Sgourou, E. N.; Londos, C. A.; Schwingenschlö gl, Udo

    2015-01-01

    Silicon and silicon germanium are the archetypical elemental and alloy semiconductor materials for nanoelectronic, sensor, and photovoltaic applications. The investigation of radiation induced defects involving oxygen, carbon, and intrinsic defects is important for the improvement of devices as these defects can have a deleterious impact on the properties of silicon and silicon germanium. In the present review, we mainly focus on oxygen-related defects and the impact of isovalent doping on their properties in silicon and silicon germanium. The efficacy of the isovalent doping strategies to constrain the oxygen-related defects is discussed in view of recent infrared spectroscopy and density functional theory studies.

  16. Influence of irradiation defects on anelastic properties of magnesium

    International Nuclear Information System (INIS)

    Minier, C.; Haneczok, G.; Lauzier, J.

    1985-01-01

    Irradiation defects in magnesium and their interactions with dislocations are studied by internal friction and elastic modulus. Long distance migration of different defects are determined. Relaxation peaks at very low temperature are analyzed. In the interaction peak between defects and dislocations it is shown that defects are interstitials and that dislocations are responsible for the peak B 1 and the interaction mechanism is probably associated to a side motion of defects along the lines. Defects brought by irradiation on dislocations are used for testing Bordoni relaxation theory and variation of parameters of peak B 1 and B 2 are analyzed [fr

  17. Expression of p53/HGF/c-met/STAT3 signal in fetuses with neural tube defects.

    Science.gov (United States)

    Trovato, Maria; D'Armiento, Maria; Lavra, Luca; Ulivieri, Alessandra; Dominici, Roberto; Vitarelli, Enrica; Grosso, Maddalena; Vecchione, Raffaella; Barresi, Gaetano; Sciacchitano, Salvatore

    2007-02-01

    Neural tube defects (NTD) are morphogenetic alterations due to a defective closure of neural tube. Hepatocyte growth factor (HGF)/c-met system plays a role in morphogenesis of nervous system, lung, and kidney. HGF/c-met morphogenetic effects are mediated by signal transducers and activators of transcription (STAT)3 and both HGF and c-met genes are regulated from p53. The aim of our study was to analyze mRNA and protein expressions of p53, HGF, c-met, and STAT3 in fetuses with NTD. By reverse transcriptase-polymerase chain reaction and immunohistochemistry, we analyzed neural tissues from four NTD fetuses and the corresponding non-malformed lungs, kidneys and placentas. We found a reduced mRNA expression of HGF/c-met/STAT3 pathway, in the malformed nervous systems and placentas. The reduced expression of this pathway correlated with the absence of p53 in all these samples. On the contrary, detectable expression levels of p53, HGF, c-met, and STAT3 were observed in non-malformed lungs and kidneys obtained from the same fetuses. Comparable results were obtained by immunohistochemistry, with the exception of p53, which was undetected in all fetal tissues. In conclusion, in NTD fetuses, both the defective neural tube tissue and the placenta have a reduction in all components of the p53/HGF/c-met/STAT3 cascade. This raises the possibility of using the suppression of these genes for early diagnosis of NTD especially on chorionic villus sampling.

  18. Garbage collection for reversible functional languages

    DEFF Research Database (Denmark)

    Mogensen, Torben Ægidius

    2015-01-01

    Reversible languages are programming languages where all programs can run both forwards and backwards. Reversible functional languages have been proposed that use symmetric pattern matching and data construction. To be reversible, these languages require linearity: Every variable must be used...

  19. Dipolar and quadrupolar defects in a transport line

    International Nuclear Information System (INIS)

    Leleux, G.; Nghiem, P.

    1991-01-01

    The defects on a transport line of linear accelerator are studied. A transport line where the elements are influenced by the design or position defects is analyzed. Only dipolar and quadrupolar defects are considered, and the coupling betwen transversal motions are excluded. The data from the literature and those calculated by transfer matrices are compared. The defects on a line are considered from an analytical point of view. Closed optical structures are also studied [fr

  20. Creation of radiation defects in KCl crystals

    International Nuclear Information System (INIS)

    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

  1. END-OF-USE PRODUCTS IN REVERSE LOGISTICS

    OpenAIRE

    Marta Starostka-Patyk

    2007-01-01

    Reverse logistics is a very useful tool for enterprises which have to deal with end-of-use products. Forward logistics is not able to manage them, because they show up on the beginning of reverse supply chain. That is the reason for growing importance of reverse flows. Reverse logistics is quite new logistics system. This paper presents the idea of reverse logistics and end-of-use products problems.

  2. Defects in Cu(In,Ga)Se{sub 2} chalcopyrite semiconductors: a comparative study of material properties, defect states, and photovoltaic performance

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Qing; Gunawan, Oki; Copel, Matthew; Reuter, Kathleen B; Chey, S Jay; Mitzi, David B [IBM T.J. Watson Research Center, Yorktown Heights, NY (United States); Deline, Vaughn R [IBM Almaden Resesarch Center, San Jose, CA (United States)

    2011-10-15

    Understanding defects in Cu(In,Ga)(Se,S){sub 2} (CIGS), especially correlating changes in the film formation process with differences in material properties, photovoltaic (PV) device performance, and defect levels extracted from admittance spectroscopy, is a critical but challenging undertaking due to the complex nature of this polycrystalline compound semiconductor. Here we present a systematic comparative study wherein varying defect density levels in CIGS films were intentionally induced by growing CIGS grains using different selenium activity levels. Material characterization results by techniques including X-ray diffraction, scanning electron microscopy, transmission electron microscopy, secondary ion mass spectrometry, X-ray photoelectron spectroscopy, and medium energy ion scattering indicate that this process variation, although not significantly affecting CIGS grain structure, crystal orientation, or bulk composition, leads to enhanced formation of a defective chalcopyrite layer with high density of indium or gallium at copper antisite defects ((In, Ga){sub Cu}) near the CIGS surface, for CIGS films grown with insufficient selenium supply. This defective layer or the film growth conditions associated with it is further linked with observed current-voltage characteristics, including rollover and crossover behavior, and a defect state at around 110 meV (generally denoted as the N1 defect) commonly observed in admittance spectroscopy. The impact of the (In, Ga){sub Cu} defects on device PV performance is also established. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Reversal of subtidal dune asymmetries caused by seasonally reversing wind-driven currents in Torres Strait, northeastern Australia

    Science.gov (United States)

    Harris, Peter T.

    1991-07-01

    Large subtidal sand dunes (sandwaves) located in Adolphus Channel, Torres Strait, have been observed to reverse their asymmetric orientation between September-February. This has been attributed to a reversal in wind-driven currents, which flow westward during the SE trade season (April-November) and eastwards during the NW monsoon season [December-March: HARRIS (1989) Continental Shelf Research, 9, 981-1002]. Observations in September 1988 and February 1989 from another area of dunes in Torres Strait corroborate this asymmetry reversal pattern. The results indicate that such reversals may be common in Torres Strait and in other areas where subtidal bedforms are subject to modification by superimposed, seasonally reversing, wind-driven currents.

  4. Endocardial cushion defect

    Science.gov (United States)

    ... 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- ...

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

    International Nuclear Information System (INIS)

    Ali, Akbar; Majid, Abdul

    2008-01-01

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

  6. Tuning the relative concentration ratio of bulk defects to surface defects in TiO2 nanocrystals leads to high photocatalytic efficiency.

    Science.gov (United States)

    Kong, Ming; Li, Yuanzhi; Chen, Xiong; Tian, Tingting; Fang, Pengfei; Zheng, Feng; Zhao, Xiujian

    2011-10-19

    TiO(2) nanocrystals with tunable bulk/surface defects were synthesized and characterized with TEM, XRD, BET, positron annihilation, and photocurrent measurements. The effect of defects on photocatalytic activity was studied. It was found for the first time that decreasing the relative concentration ratio of bulk defects to surface defects in TiO(2) nanocrystals could significantly improve the separation efficiency of photogenerated electrons and holes, thus significantly enhancing the photocatalytic efficiency.

  7. The study of the identification of minimal defects in radiograph, 2

    International Nuclear Information System (INIS)

    Senda, Tomio; Hirayama, Kazuo; Yokoyama, Keiji; Nakamura, Kazuo.

    1988-01-01

    In the first report, it was discussed in terms of the mass on the detectible limit of such minimal defects of cylindrical defect as a representative of ingot-defect and slit defect as a representative of plate-defect respectively which generally appear on the weld joints, using contrast distribution area of defects on the radiograph. In the second report, an experiment is done to vary the contrast of radiograph by dual exposure system and to vary the radiation by rotating photographing in order to investigate the corresponding relation of defectible limit of defect dimension between cylindrical defect and slit defect. (author)

  8. Study of domain depinning during repeated polarization reversal in hard PZT ceramics using acoustic emission

    International Nuclear Information System (INIS)

    Prabakar, K; Rao, S P Mallikarjun

    2006-01-01

    Acoustic emission (AE) has been studied during repeated polarization reversals (at 50 Hz) in hard PZT-8 ceramics. The AE and hysteresis loop were monitored at regular intervals of electric field (±20 kV cm -1 peak) application till 10 8 cycles. The sample did not fatigue and an increase in saturation polarization (Ps) was observed. AE was observed with zero threshold till 10 5 cycles when the field was increasing in both half cycles of the applied field. The initial increase in AE activity with increasing number of field cycles till 10 5 was explained on the basis of defect dipoles encouraging the 90 deg. domain switches, i.e. domain depinning. The decrease in AE activity, an increase in threshold field for the observed AE and a further increase in Ps after 10 5 cycles were explained based on the changes in the orientation of defect dipoles with respect to Ps due to the applied field cycles. This was found to encourage the 180 0 domain switches but pin the 90 deg. domains. An increase in AE at 10 8 cycles after applying a higher field of ±25 kV cm -1 was found to be mainly due to microcracking

  9. Di-interstitial defect in silicon revisited

    International Nuclear Information System (INIS)

    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

  10. Defect networks and supersymmetric loop operators

    Energy Technology Data Exchange (ETDEWEB)

    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.

  11. Magnetic reversals from planetary dynamo waves.

    Science.gov (United States)

    Sheyko, Andrey; Finlay, Christopher C; Jackson, Andrew

    2016-11-24

    A striking feature of many natural dynamos is their ability to undergo polarity reversals. The best documented example is Earth's magnetic field, which has reversed hundreds of times during its history. The origin of geomagnetic polarity reversals lies in a magnetohydrodynamic process that takes place in Earth's core, but the precise mechanism is debated. The majority of numerical geodynamo simulations that exhibit reversals operate in a regime in which the viscosity of the fluid remains important, and in which the dynamo mechanism primarily involves stretching and twisting of field lines by columnar convection. Here we present an example of another class of reversing-geodynamo model, which operates in a regime of comparatively low viscosity and high magnetic diffusivity. This class does not fit into the paradigm of reversal regimes that are dictated by the value of the local Rossby number (the ratio of advection to Coriolis force). Instead, stretching of the magnetic field by a strong shear in the east-west flow near the imaginary cylinder just touching the inner core and parallel to the axis of rotation is crucial to the reversal mechanism in our models, which involves a process akin to kinematic dynamo waves. Because our results are relevant in a regime of low viscosity and high magnetic diffusivity, and with geophysically appropriate boundary conditions, this form of dynamo wave may also be involved in geomagnetic reversals.

  12. Multiple reversal olfactory learning in honeybees

    Directory of Open Access Journals (Sweden)

    Theo Mota

    2010-07-01

    Full Text Available In multiple reversal learning, animals trained to discriminate a reinforced from a non-reinforced stimulus are subjected to various, successive reversals of stimulus contingencies (e.g. A+ vs. B-, A- vs. B+, A+ vs. B-. This protocol is useful to determine whether or not animals learn to learn and solve successive discriminations faster (or with fewer errors with increasing reversal experience. Here we used the olfactory conditioning of proboscis extension reflex to study how honeybees Apis mellifera perform in a multiple reversal task. Our experiment contemplated four consecutive differential conditioning phases involving the same odors (A+ vs. B- to A- vs. B+ to A+ vs. B- to A- vs. B+. We show that bees in which the weight of reinforced or non-reinforced stimuli was similar mastered the multiple olfactory reversals. Bees which failed the task exhibited asymmetric responses to reinforced and non-reinforced stimuli, thus being unable to rapidly reverse stimulus contingencies. Efficient reversers did not improve their successive discriminations but rather tended to generalize their choice to both odors at the end of conditioning. As a consequence, both discrimination and reversal efficiency decreasedalong experimental phases. This result invalidates a learning-to-learn effect and indicates that bees do not only respond to the actual stimulus contingencies but rather combine these with an average of past experiences with the same stimuli.  

  13. Reversibility: An Engineer's Point of View

    Energy Technology Data Exchange (ETDEWEB)

    Berest, Pierre [LMS, ecole Polytechnique (France)

    2012-07-01

    Reversibility is the most consistent option in a democratic country. However reversibility may also have several drawbacks which must be identified and mitigated. Reversibility of a geological repository is a relatively new idea in France. The 1991 law dedicated to nuclear waste management considered reversibility as a possible option. Fifteen years later, the 2006 law mandated that a deep repository must be reversible and that the exact content of this notion should be defined by a new law to be discussed by the Parliament in 2015. Reversibility was not a concern put forward by engineers. It clearly originated from a societal demand sponsored and formulated by the Parliament. Since 1991, the exact meaning of this mandate progressively became more precise. In the early days, reversibility meant the technical and financial capability to retrieve the wastes from the repository, at least for some period of time after being emplaced. Progressively, a broader definition, suggested by Andra, was accepted: reversibility also means that a disposal facility should be operated in such a way that a stepwise decision-making process is possible. At each step, society must be able to decide to proceed to the next step, to pause or to reverse a step. Several benefits can be expected from a reversible repository. Some technical safety concerns may be only recognised after waste emplacement. Radioactive wastes may become a resource whose recoverability is desirable. Regulations may change, alternative waste treatment or better disposal techniques may be developed, or the need to modify a component of the facility may arise. Looking back at how chemical or domestic wastes were managed some 50 years ago easily underscores that it is not unreasonable to hope for significant advances in the future. For scientists and engineers, reversibility proves to have several other merits. To design and build a good repository, time is needed. The operator of a mine or of an oil field knows that

  14. Imaging active topological defects in carbon nanotubes

    Science.gov (United States)

    Suenaga, Kazu; Wakabayashi, Hideaki; Koshino, Masanori; Sato, Yuta; Urita, Koki; Iijima, Sumio

    2007-06-01

    A single-walled carbon nanotube (SWNT) is a wrapped single graphene layer, and its plastic deformation should require active topological defects-non-hexagonal carbon rings that can migrate along the nanotube wall. Although in situ transmission electron microscopy (TEM) has been used to examine the deformation of SWNTs, these studies deal only with diameter changes and no atomistic mechanism has been elucidated experimentally. Theory predicts that some topological defects can form through the Stone-Wales transformation in SWNTs under tension at 2,000 K, and could act as a dislocation core. We demonstrate here, by means of high-resolution (HR)-TEM with atomic sensitivity, the first direct imaging of pentagon-heptagon pair defects found in an SWNT that was heated at 2,273 K. Moreover, our in situ HR-TEM observation reveals an accumulation of topological defects near the kink of a deformed nanotube. This result suggests that dislocation motions or active topological defects are indeed responsible for the plastic deformation of SWNTs.

  15. Tritium releases, birth defects and infant deaths

    International Nuclear Information System (INIS)

    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

  16. Phase-enhanced defect sensitivity for EUV mask inspection

    Science.gov (United States)

    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.

  17. Thermophysical spectroscopy of defect states in silicon

    International Nuclear Information System (INIS)

    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

  18. Synthesis and electrochemical study of Mg{sub 1.5}MnO{sub 3}: A defect spinel cathode for rechargeable magnesium battery

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Partha [Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); US Department of Energy, National Energy Technology Laboratory, Morgantown, WV 26507 (United States); Jampani, Prashanth H., E-mail: pjampani@pitt.edu [Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); Hong, DaeHo [Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); Gattu, Bharat [Mechanical Engineering and Materials Science, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); Poston, James A.; Manivannan, Ayyakkannu [US Department of Energy, National Energy Technology Laboratory, Morgantown, WV 26507 (United States); Datta, Moni Kanchan [Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); US Department of Energy, National Energy Technology Laboratory, Morgantown, WV 26507 (United States); Kumta, Prashant N., E-mail: pkumta@pitt.edu [Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); US Department of Energy, National Energy Technology Laboratory, Morgantown, WV 26507 (United States); Mechanical Engineering and Materials Science, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); Chemical and Petroleum Engineering, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); School of Dental Medicine, University of Pittsburgh, PA 15261 (United States); Center for Complex Engineered Multifunctional Materials, University of Pittsburgh, Pittsburgh, PA 15261 (United States)

    2015-12-15

    Graphical abstract: Mg{sub 1.5}MnO{sub 3}, a defect oxide spinel derived by the Pechini route, was tested as cathode for rechargeable magnesium battery. TEM and XRD analyses of Mg{sub 1.5}MnO{sub 3} shows the formation of ∼100 nm sized nano particles in the cubic defect spinel structure (space group: Fd3m; unit cell: 0.833294 nm). Cyclic voltammetry illustrates a reversible reaction occurring between 0.3 and 1.5 V versus magnesium. Galvanostatic cycling of the Mg{sub 1.5}MnO{sub 3} cathode exhibits a low capacity of ∼12.4 mAh/g up to 20 cycle with ∼99.9% Coulombic efficiency when cycled at a current rate of ∼C/27. XPS (X-ray photoelectron spectroscopy) surface probe of magnesiated/de-magnesiated electrodes confirm a change in the redox center of Mn-ions during intercalation/de-intercalation of Mg-ion from the Mg{sub 1.5}MnO{sub 3} electrode. The low capacity of Mg{sub 1.5}MnO{sub 3} electrode mainly stem from the kinetic limitation of Mg-ion removal from the defect oxide spinel as the electrochemical impedance spectroscopy results of electrodes after 1st and 2nd cycle show that charge transfer resistance, R{sub e}, increases post charge state whereas interfacial resistance, R{sub i}, increases after discharge state, respectively. - Highlights: • Pechini process yields 100 nm sized particles of the defect cubic spinel Mg{sub 1.5}MnO{sub 3}. • Stable capacity of ∼12.4 mAh/g obtained at C/27 rate and 99.9% Coulombic efficiency. • XPS shows change in valence state of Mn{sup 3+}/Mn{sup 4+} center with cycling. • Low capacity stems from increase in charge-transfer and interfacial resistances with cycling. - Abstract: Mg{sub 1.5}MnO{sub 3}, a defect oxide spinel (space group: Fd3m; unit cell: 0.833294 nm) of particle size ∼100 nm derived by the Pechini route was tested as a cathode for rechargeable magnesium battery. Cyclic voltammetry illustrates a reversible reaction occurring in the 0.3–2.0 V potential window versus magnesium. The spinel however

  19. Reversible and non-reversible enlargement of cerebral spinal fluid spaces in anorexia nervosa

    International Nuclear Information System (INIS)

    Artmann, H.; Grau, H.; Adelmann, M.; Schleiffer, R.

    1985-01-01

    Brain CT studies of 35 patients with anoxia nervosa confirmed the observations of other authors: cerebral dystrophic changes correlate with weight loss and the reversibility of these changes also correlates with the normalization of body weight. Other corroborated facts are: the most numerous and most pronounced enlargements are of the cortical sulci and the interhemispheric fissure, moderate widening affects the ventricles and the rarest and most insignificant changes are those of the cerebellum. The reversibility of the changes showed a parallel to the extent of the changes themselves and to the duration of improvement of the body weight. The reversibility of the enlargement of the cortical sulci and of the distances between the frontal horns of the lateral ventricles was more often significant than that of the abnormal measurements of the cella media. This difference is based on minimal early acquired brain damage which occurs in 60% of our patients. This high incidence of early acquired minimal brain disease in patients with anorexia nervosa is here discussed as a nonspecific predisposing factor. Although there is no exact explanation of the etiology of the reversible enlargement of cerenral spinal fluid (CSF) spaces in anorexia nervosa, the changes resemble those in alcoholics. The mechanisms of brain changes in alcoholism, as shown experimentally, seem to us to throw light on the probable mechanism of reversible dystrophic brain changes in anorexia nervosa. (orig.)

  20. Reversible and non-reversible enlargement of cerebral spinal fluid spaces in anorexia nervosa

    Energy Technology Data Exchange (ETDEWEB)

    Artmann, H.; Grau, H.; Adelmann, M.; Schleiffer, R.

    1985-07-01

    Brain CT studies of 35 patients with anoxia nervosa confirmed the observations of other authors: cerebral dystrophic changes correlate with weight loss and the reversibility of these changes also correlates with the normalization of body weight. Other corroborated facts are: the most numerous and most pronounced enlargements are of the cortical sulci and the interhemispheric fissure, moderate widening affects the ventricles and the rarest and most insignificant changes are those of the cerebellum. The reversibility of the changes showed a parallel to the extent of the changes themselves and to the duration of improvement of the body weight. The reversibility of the enlargement of the cortical sulci and of the distances between the frontal horns of the lateral ventricles was more often significant than that of the abnormal measurements of the cella media. This difference is based on minimal early acquired brain damage which occurs in 60% of our patients. This high incidence of early acquired minimal brain disease in patients with anorexia nervosa is here discussed as a nonspecific predisposing factor. Although there is no exact explanation of the etiology of the reversible enlargement of cerenral spinal fluid (CSF) spaces in anorexia nervosa, the changes resemble those in alcoholics. The mechanisms of brain changes in alcoholism, as shown experimentally, seem to us to throw light on the probable mechanism of reversible dystrophic brain changes in anorexia nervosa.

  1. Characterization of the structure and chemistry of defects in materials

    International Nuclear Information System (INIS)

    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

  2. Point defects dynamics in a stress field

    International Nuclear Information System (INIS)

    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

  3. Residual Defect Density in Random Disks Deposits.

    Science.gov (United States)

    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.

  4. Correlated and uncorrelated invisible temporal white noise alters mesopic rod signaling.

    Science.gov (United States)

    Hathibelagal, Amithavikram R; Feigl, Beatrix; Kremers, Jan; Zele, Andrew J

    2016-03-01

    We determined how rod signaling at mesopic light levels is altered by extrinsic temporal white noise that is correlated or uncorrelated with the activity of one (magnocellular, parvocellular, or koniocellular) postreceptoral pathway. Rod and cone photoreceptor excitations were independently controlled using a four-primary photostimulator. Psychometric (Weibull) functions were measured for incremental rod pulses (50 to 250 ms) in the presence (or absence; control) of perceptually invisible subthreshold extrinsic noise. Uncorrelated (rod) noise facilitates rod detection. Correlated postreceptoral pathway noise produces differential changes in rod detection thresholds and decreases the slope of the psychometric functions. We demonstrate that invisible extrinsic noise changes rod-signaling characteristics within the three retinogeniculate pathways at mesopic illumination depending on the temporal profile of the rod stimulus and the extrinsic noise type.

  5. Reversal agents in anaesthesia and critical care

    Directory of Open Access Journals (Sweden)

    Nibedita Pani

    2015-01-01

    Full Text Available Despite the advent of short and ultra-short acting drugs, an in-depth knowledge of the reversal agents used is a necessity for any anaesthesiologist. Reversal agents are defined as any drug used to reverse the effects of anaesthetics, narcotics or potentially toxic agents. The controversy on the routine reversal of neuromuscular blockade still exists. The advent of newer reversal agents like sugammadex have made the use of steroidal neuromuscular blockers like rocuronium feasible in rapid sequence induction situations. We made a review of the older reversal agents and those still under investigation for drugs that are regularly used in our anaesthesia practice.

  6. Nonlinear defect localized modes and composite gray and anti-gray solitons in one-dimensional waveguide arrays with dual-flip defects

    Science.gov (United States)

    Liu, Yan; Guan, Yefeng; Li, Hai; Luo, Zhihuan; Mai, Zhijie

    2017-08-01

    We study families of stationary nonlinear localized modes and composite gray and anti-gray solitons in a one-dimensional linear waveguide array with dual phase-flip nonlinear point defects. Unstaggered fundamental and dipole bright modes are studied when the defect nonlinearity is self-focusing. For the fundamental modes, symmetric and asymmetric nonlinear modes are found. Their stable areas are studied using different defect coefficients and their total power. For the nonlinear dipole modes, the stability conditions of this type of mode are also identified by different defect coefficients and the total power. When the defect nonlinearity is replaced by the self-defocusing one, staggered fundamental and dipole bright modes are created. Finally, if we replace the linear waveguide with a full nonlinear waveguide, a new type of gray and anti-gray solitons, which are constructed by a kink and anti-kink pair, can be supported by such dual phase-flip defects. In contrast to the usual gray and anti-gray solitons formed by a single kink, their backgrounds on either side of the gray hole or bright hump have the same phase.

  7. The misconception of mean-reversion

    International Nuclear Information System (INIS)

    Eliazar, Iddo I; Cohen, Morrel H

    2012-01-01

    The notion of random motion in a potential well is elemental in the physical sciences and beyond. Quantitatively, this notion is described by reverting diffusions—asymptotically stationary diffusion processes which are simultaneously (i) driven toward a reversion level by a deterministic force, and (ii) perturbed off the reversion level by a random white noise. The archetypal example of reverting diffusions is the Ornstein–Uhlenbeck process, which is mean-reverting. In this paper we analyze reverting diffusions and establish that: (i) if the magnitude of the perturbing noise is constant then the diffusion's stationary density is unimodal and the diffusion is mode-reverting; (ii) if the magnitude of the perturbing noise is non-constant then, in general, neither is the diffusion's stationary density unimodal, nor is the diffusion mode-reverting. In the latter case we further establish a result asserting when unimodality and mode-reversion do hold. In particular, we demonstrate that the notion of mean-reversion, which is fundamental in economics and finance, is a misconception—as mean-reversion is an exception rather than the norm. (fast track communication)

  8. Percutaneous treatment of atrial septal defects, muscular ventricular septal defects and patent ductus arteriosus in infants under one year of age.

    Science.gov (United States)

    Prada, Fredy; Mortera, Carlos; Bartrons, Joaquim; Rissech, Miguel; Jiménez, Lorenzo; Carretero, Juan; Llevadias, Judit; Araica, Mireya

    2009-09-01

    Amplatzer devices are used for the percutaneous closure of ostium secundum atrial septal defects, muscular ventricular septal defects and patent ductus arteriosus. However, very little experience has been gained in using these devices in infants under 1 year of age. Between January 2001 and January 2008, 22 symptomatic infants aged under 1 year underwent percutaneous treatment: three had an ostium secundum atrial septal defect, 15 had patent ductus arteriosus, and four had a muscular ventricular septal defect. All the procedures were completed successfully. No immediate or medium-term complications were observed. Closure of these types of defect using an Amplatzer device in infants under 1 year of age, who would otherwise require surgery, is a safe and effective procedure.

  9. A new fundamental hydrogen defect in alkali halides

    International Nuclear Information System (INIS)

    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

  10. Characterization of lacunar defects by positrons annihilation

    International Nuclear Information System (INIS)

    Barthe, M.F.; Corbel, C.; Blondiaux, G.

    2003-01-01

    Among the nondestructive methods for the study of matter, the positrons annihilation method allows to sound the electronic structure of materials by measuring the annihilation characteristics. These characteristics depend on the electronic density as seen by the positon, and on the electron momentums distribution which annihilate with the positon. The positon is sensible to the coulombian potential variations inside a material and sounds preferentially the regions away from nuclei which represent potential wells. The lacunar-type defects (lack of nuclei) represent deep potential wells which can trap the positon up to temperatures close to the melting. This article describes the principles of this method and its application to the characterization of lacunar defects: 1 - positrons: matter probes (annihilation of electron-positon pairs, annihilation characteristics, positrons sources); 2 - positrons interactions in solids (implantation profiles, annihilation states, diffusion and trapping, positon lifetime spectrum: evolution with the concentration of defects); 3 - measurement of annihilation characteristics with two gamma photons (lifetime spectroscopy with the β + 22 Na isotope, spectroscopy of Doppler enlargement of the annihilation line); 4 - determination of the free volume of defects inside or at the surface of materials (annihilation signature in lacunar defects, lacuna, lacunar clusters and cavities, acceptors nature in semiconductors: ionic or lacunar, interface defects, precipitates in alloys); 5 - conclusions. (J.S.)

  11. Parkinson’s disease managing reversible neurodegeneration

    Science.gov (United States)

    Hinz, Marty; Stein, Alvin; Cole, Ted; McDougall, Beth; Westaway, Mark

    2016-01-01

    Traditionally, the Parkinson’s disease (PD) symptom course has been classified as an irreversible progressive neurodegenerative disease. This paper documents 29 PD and treatment-induced systemic depletion etiologies which cause and/or exacerbate the seven novel primary relative nutritional deficiencies associated with PD. These reversible relative nutritional deficiencies (RNDs) may facilitate and accelerate irreversible progressive neurodegeneration, while other reversible RNDs may induce previously undocumented reversible pseudo-neurodegeneration that is hiding in plain sight since the symptoms are identical to the symptoms being experienced by the PD patient. Documented herein is a novel nutritional approach for reversible processes management which may slow or halt irreversible progressive neurodegenerative disease and correct reversible RNDs whose symptoms are identical to the patient’s PD symptoms. PMID:27103805

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

    Science.gov (United States)

    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.

  13. Key Questions in Building Defect Prediction Models in Practice

    Science.gov (United States)

    Ramler, Rudolf; Wolfmaier, Klaus; Stauder, Erwin; Kossak, Felix; Natschläger, Thomas

    The information about which modules of a future version of a software system are defect-prone is a valuable planning aid for quality managers and testers. Defect prediction promises to indicate these defect-prone modules. However, constructing effective defect prediction models in an industrial setting involves a number of key questions. In this paper we discuss ten key questions identified in context of establishing defect prediction in a large software development project. Seven consecutive versions of the software system have been used to construct and validate defect prediction models for system test planning. Furthermore, the paper presents initial empirical results from the studied project and, by this means, contributes answers to the identified questions.

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

    Science.gov (United States)

    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.

  15. Dislocation defect interaction in irradiated Cu

    International Nuclear Information System (INIS)

    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

  16. Elastic interaction energies of defect structures

    International Nuclear Information System (INIS)

    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

  17. Photometric estimation of defect size in radiation direction

    International Nuclear Information System (INIS)

    Zuev, V.M.

    1993-01-01

    Factors, affecting accuracy of photometric estimation of defect size in radiation transmission direction, are analyzed. Experimentally obtained dependences of contrast of defect image on its size in radiation transmission direction are presented. Practical recommendations on improving accuracy of photometric estimation of defect size in radiation transmission direction, are developed

  18. Inspection of surface defects for cladding tube with laser

    International Nuclear Information System (INIS)

    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.)

  19. Reversible machine code and its abstract processor architecture

    DEFF Research Database (Denmark)

    Axelsen, Holger Bock; Glück, Robert; Yokoyama, Tetsuo

    2007-01-01

    A reversible abstract machine architecture and its reversible machine code are presented and formalized. For machine code to be reversible, both the underlying control logic and each instruction must be reversible. A general class of machine instruction sets was proven to be reversible, building...

  20. Progranulin modulates zebrafish motoneuron development in vivo and rescues truncation defects associated with knockdown of Survival motor neuron 1

    Directory of Open Access Journals (Sweden)

    Bateman Andrew

    2010-10-01

    Full Text Available Abstract Background Progranulin (PGRN encoded by the GRN gene, is a secreted glycoprotein growth factor that has been implicated in many physiological and pathophysiological processes. PGRN haploinsufficiency caused by autosomal dominant mutations within the GRN gene leads to progressive neuronal atrophy in the form of frontotemporal lobar degeneration (FTLD. This form of the disease is associated with neuronal inclusions that bear the ubiquitinated TAR DNA Binding Protein-43 (TDP-43 molecular signature (FTLD-U. The neurotrophic properties of PGRN in vitro have recently been reported but the role of PGRN in neurons is not well understood. Here we document the neuronal expression and functions of PGRN in spinal cord motoneuron (MN maturation and branching in vivo using zebrafish, a well established model of vertebrate embryonic development. Results Whole-mount in situ hybridization and immunohistochemical analyses of zebrafish embryos revealed that zfPGRN-A is expressed within the peripheral and central nervous systems including the caudal primary (CaP MNs within the spinal cord. Knockdown of zfPGRN-A mRNA translation mediated by antisense morpholino oligonucleotides disrupted normal CaP MN development resulting in both truncated MNs and inappropriate early branching. Ectopic over-expression of zfPGRN-A mRNA resulted in increased MN branching and rescued the truncation defects brought about by knockdown of zfPGRN-A expression. The ability of PGRN to interact with established MN developmental pathways was tested. PGRN over-expression was found to reverse the truncation defect resulting from knockdown of Survival of motor neuron 1 (smn1. This is involved in small ribonucleoprotein biogenesis RNA processing, mutations of which cause Spinal Muscular Atrophy (SMA in humans. It did not reverse the MN defects caused by interfering with the neuronal guidance pathway by knockdown of expression of NRP-1, a semaphorin co-receptor. Conclusions Expression of

  1. Immersion lithography defectivity analysis at DUV inspection wavelength

    Science.gov (United States)

    Golan, E.; Meshulach, D.; Raccah, N.; Yeo, J. Ho.; Dassa, O.; Brandl, S.; Schwarz, C.; Pierson, B.; Montgomery, W.

    2007-03-01

    Significant effort has been directed in recent years towards the realization of immersion lithography at 193nm wavelength. Immersion lithography is likely a key enabling technology for the production of critical layers for 45nm and 32nm design rule (DR) devices. In spite of the significant progress in immersion lithography technology, there remain several key technology issues, with a critical issue of immersion lithography process induced defects. The benefits of the optical resolution and depth of focus, made possible by immersion lithography, are well understood. Yet, these benefits cannot come at the expense of increased defect counts and decreased production yield. Understanding the impact of the immersion lithography process parameters on wafer defects formation and defect counts, together with the ability to monitor, control and minimize the defect counts down to acceptable levels is imperative for successful introduction of immersion lithography for production of advanced DR's. In this report, we present experimental results of immersion lithography defectivity analysis focused on topcoat layer thickness parameters and resist bake temperatures. Wafers were exposed on the 1150i-α-immersion scanner and 1200B Scanner (ASML), defect inspection was performed using a DUV inspection tool (UVision TM, Applied Materials). Higher sensitivity was demonstrated at DUV through detection of small defects not detected at the visible wavelength, indicating on the potential high sensitivity benefits of DUV inspection for this layer. The analysis indicates that certain types of defects are associated with different immersion process parameters. This type of analysis at DUV wavelengths would enable the optimization of immersion lithography processes, thus enabling the qualification of immersion processes for volume production.

  2. Acemannan sponges stimulate alveolar bone, cementum and periodontal ligament regeneration in a canine class II furcation defect model.

    Science.gov (United States)

    Chantarawaratit, P; Sangvanich, P; Banlunara, W; Soontornvipart, K; Thunyakitpisal, P

    2014-04-01

    Periodontal disease is a common infectious disease, found worldwide, causing the destruction of the periodontium. The periodontium is a complex structure composed of both soft and hard tissues, thus an agent applied to regenerate the periodontium must be able to stimulate periodontal ligament, cementum and alveolar bone regeneration. Recent studies demonstrated that acemannan, a polysaccharide extracted from Aloe vera gel, stimulated both soft and hard tissue healing. This study investigated effect of acemannan as a bioactive molecule and scaffold for periodontal tissue regeneration. Primary human periodontal ligament cells were treated with acemannan in vitro. New DNA synthesis, expression of growth/differentiation factor 5 and runt-related transcription factor 2, expression of vascular endothelial growth factor, bone morphogenetic protein-2 and type I collagen, alkaline phosphatase activity, and mineralized nodule formation were determined using [(3)H]-thymidine incorporation, reverse transcription-polymerase chain reaction, enzyme-linked immunoabsorbent assay, biochemical assay and alizarin red staining, respectively. In our in vivo study, premolar class II furcation defects were made in four mongrel dogs. Acemannan sponges were applied into the defects. Untreated defects were used as a negative control group. The amount of new bone, cementum and periodontal ligament formation were evaluated 30 and 60 d after the operation. Acemannan significantly increased periodontal ligament cell proliferation, upregulation of growth/differentiation factor 5, runt-related transcription factor 2, vascular endothelial growth factor, bone morphogenetic protein 2, type I collagen and alkaline phosphatase activity, and mineral deposition as compared with the untreated control group in vitro. Moreover, acemannan significantly accelerated new alveolar bone, cementum and periodontal ligament formation in class II furcation defects. Our data suggest that acemannan could be a candidate

  3. Defect sizing using automated ultrasonic inspection techniques at RNL

    International Nuclear Information System (INIS)

    Rogerson, A.; Highmore, P.J.; Poulter, L.N.J.

    1983-10-01

    RNL has developed and applied automated wide-beam pulse-echo and time-of-flight techniques with synthetic aperture processing for sizing defects in clad thick-section weldments and nozzle corner regions. These techniques were amongst those used in the four test plate inspections making up the UKAEA Defect Detection Trials. In this report a critical appraisal is given of the sizing procedures adopted by RNL in these inspections. Several factors influencing sizing accuracy are discussed and results from particular defects highlighted. The time-of-flight technique with colour graphics data display is shown to be highly effective in imaging near-vertical buried defects and underclad defects of height greater than 5 mm. Early characterisation of any identified defect from its ultrasonic response under pulse-echo inspection is seen as a desirable aid to the selection of an appropriate advanced sizing technique for buried defects. (author)

  4. Size Effect of Defects on the Mechanical Properties of Graphene

    Science.gov (United States)

    Park, Youngho; Hyun, Sangil

    2018-03-01

    Graphene, a two-dimensional material, has been studied and utilized for its excellent material properties. In reality, achieving a pure single-crystalline structure in graphene is difficult, so usually graphene may have various types of defects in it. Vacancies, Stone-Wales defects, and grain boundaries can drastically change the material properties of graphene. Graphene with vacancy defects has been of interest because it is a two-dimensional analogy of three-dimensional porous materials. It has efficient material properties, and can function as a part of modern devices. The mechanical properties have been studied by using molecular dynamics for either a single vacancy defect with various sizes or multiple vacancy defects with same defect ratios. However, it is not clear which one has more influence on the mechanical properties between the size of the defects and the defect ratio. Therefore, we investigated the hole-size effect on the mechanical properties of single-crystalline graphene at various defect ratios. A void defect with large size can have a rather high tensile modulus with a low fracture strain compared to a void defect with small size. We numerically found that the tensile properties of scattered single vacancies is similar to that of amorphous graphene. We suspect that this is due to the local orbital change of the carbon atoms near the boundary of the void defects, so-called the interfacial phase.

  5. A Typology of Reverse Innovation

    DEFF Research Database (Denmark)

    von Zedtwitz, Max; Corsi, Simone; Søberg, Peder Veng

    2015-01-01

    secondary market introduction, this study expands the espoused definition of reverse innovation beyond its market-introduction focus with reversals in the flow of innovation in the ideation and product development phases. Recognizing that each phase can take place in different geographical locations...... taking place in an emerging country. This analytical framework allows recasting of current research at the intersection between innovation and international business. Of the 10 reverse innovation flows, six are new and have not been covered in the literature to date. The study addresses questions......’s portfolio of global innovation competence and capability. The implications for management are concerned with internal and external resistance to reverse innovation. Most significantly, while greater recognition and power of innovation in formerly subordinate organizational units is inconvenient to some...

  6. Defect structure in proton-irradiated copper and nickel

    International Nuclear Information System (INIS)

    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.)

  7. Elements of a Reversible Object-Oriented Language

    DEFF Research Database (Denmark)

    Schultz, Ulrik Pagh; Axelsen, Holger Bock

    2016-01-01

    This paper presents initial ideas for the design and implementation of a reversible object-oriented language based on extending Janus with object-oriented concepts such as classes that encapsulate behavior and state, inheritance, virtual dispatching, as well as constructors. We show that virtual...... dispatching is a reversible decision mechanism easily translatable to a standard reversible programming model such as Janus, and we argue that reversible management of state can be accomplished using reversible constructors. The language is implemented in terms of translation to standard Janus programs....

  8. Prognostic importance of silent myocardial ischemia detected by intravenous dipyridamole thallium myocardial imaging in asymptomatic patients with coronary artery disease

    International Nuclear Information System (INIS)

    Younis, L.T.; Byers, S.; Shaw, L.; Barth, G.; Goodgold, H.; Chaitman, B.R.

    1989-01-01

    One hundred seven asymptomatic patients who underwent intravenous dipyridamole thallium imaging were evaluated to determine prognostic indicators of subsequent cardiac events over an average follow-up period of 14 +/- 10 months. Univariate analysis of 18 clinical, scintigraphic and angiographic variables revealed that a reversible thallium defect, a combined fixed and reversible thallium defect, number of segmental thallium defects and extent of coronary artery disease were significant predictors of subsequent cardiac events. Of the 13 patients who died or had a nonfatal infarction, 12 had a reversible thallium defect. Stepwise logistic regression analysis selected a reversible thallium defect as the only significant predictor of cardiac events. When death or myocardial infarction was the outcome variable, a combined fixed and reversible thallium defect was the only predictor of outcome. In patients without previous myocardial infarction, the cardiac event rate was significantly greater in those with an abnormal versus normal thallium scan (55% versus 12%, p less than 0.001). Thus, intravenous dipyridamole thallium scintigraphy is a useful noninvasive test to risk stratify asymptomatic patients with coronary artery disease. A reversible thallium defect most likely indicates silent myocardial ischemia in a sizable fraction of patients in this clinical subset and is associated with an unfavorable prognosis

  9. Defect engineering of SrTiO{sub 3} thin films for resistive switching applications

    Energy Technology Data Exchange (ETDEWEB)

    Wicklein, Sebastian

    2013-11-19

    lifetime spectroscopy. The role of extrinsic dopands such as Fe is shown to have more complicated effects on the SrTiO{sub 3} system than portrayed by theoretical considerations. The effect of defects on the resistive switching properties of SrTiO{sub 3} was investigated by local conductivity AFM. Defect engineered SrTiO{sub 3} depict variations of the resistive switching properties for different defect constellations within the system. More stable resistance switching was achieved for systems with an increased defect content. The mechanism of the resistance change was attributed to the rearrangement of oxygen vacancies within SrTiO{sub 3} and a theory devised where the rearrangement of the oxygen vacancies causes a reversible transition of the oxide from p- to n-type. Whereas a p-type oxide depicts a high resistance and a n-type oxide a low resistance.

  10. Reversibility of U → F processes in X or UV irradiated KCl: H- systems

    International Nuclear Information System (INIS)

    Bressiani, Ana Helena A.

    1979-01-01

    Potassium Chloride crystals, pure, additively colored or hydrogenated have been exposed to X and UV radiations for correlation studies' of formation processes of defects. In hydrogenated samples, these irradiations are responsible-for a direct U→F centers conversion with the simultaneous creation of H 2 molecules besides the intrinsic formation of F/hole centers. After prolonged irradiation, F aggregate centers react with H 2 molecules forming U center pairs. As the two U centers have independent electronic transitions they add up, increasing the maximum height of the U band after F→U reversed reation. The saturation levels of defects produced by these two types of radiation are different because UV light also excites F centers while producing them. This effect is responsible by the F center aggregation and the inversion F→U decreasing the U→F efficiency. Crystals with F and U centers under F light also show F→U inversion but with higher efficiency than when under UV light. This F→U process gives back 90% of the initial U center concentration. This same F→U process was observed but at smaller rate of formation if samples containing U, F and F aggregates are left in the dark for prolonged periods of time. The same reactions take place namely H 2 molecules annihilation F aggregates. (author)

  11. Drift reversal capability in helical systems

    International Nuclear Information System (INIS)

    Yokoyama, M.; Itoh, K.; Okamura, S.

    2002-10-01

    The maximum-J (J is the second adiabatic invariant) capability, i.e., the drift reversal capability, is examined in quasi-axisymmetric (QAS) stellarators and quasi-poloidally symmetric (QPS) stellarators as a possible mechanism for turbulent transport suppression. Due to the existence of non-axisymmetry of the magnetic field strength in QAS configurations, a local maximum of J is created to cause the drift reversal. The increase of magnetic shear in finite beta equilibria also has favorable effect in realizing the drift reversal. The radial variation of the uniform magnetic field component plays a crucial role for the drift reversal in a QPS configuration. Thus, the drift reversal capability and its external controllability are demonstrated for QAS and QPS stellarators, by which the impact of magnetic configuration on turbulent transport can be studied in experiments. (author)

  12. Drift reversal capability in helical systems

    International Nuclear Information System (INIS)

    Yokoyama, M.; Itoh, K.; Okamura, S.; Matsuoka, K.; Nakajima, N.; Itoh, S.-I.; Neilson, G.H.; Zarnstorff, M.C.; Rewoldt, G.

    2003-01-01

    The maximum-J (J is the second adiabatic invariant) capability, i.e., the drift reversal capability, is examined in quasi-axisymmetric (QAS) stellarators and quasi-poloidally symmetric (QPS) stellarators as a possible mechanism for turbulent transport suppression. Due to the existence of non-axisymmetry of the magnetic field strength in QAS configurations, a local maximum of J is created to cause the drift reversal. The increase of magnetic shear in finite beta equilibria also has favorable effect in realizing the drift reversal. The radial variation of the uniform magnetic field component plays a crucial role for the drift reversal in a QPS configuration. Thus, the drift reversal capability and its external controllability are demonstrated for QAS and QPS stellarators, by which the impact of magnetic configuration on turbulent transport can be studied in experiments. (author)

  13. Investigation of UFO defect on DUV CAR and BARC process

    Science.gov (United States)

    Yet, Siew Ing; Ko, Bong Sang; Lee, Soo Man; May, Mike

    2004-05-01

    Photo process defect reduction is one of the most important factors to improve the process stability and yield in sub-0.18um DUV process. In this paper, a new approach to minimize the Deep-UV (DUV) Chemically Amplified Resist (CAR) and Bottom Anti-Reflective Coating (BARC) induced defect known as UFO (UnidentiFied Object) defect will be introduced. These defects have mild surface topography difference on BARC; it only exists on the wide exposed area where there is no photoresist pattern. In this test, Nikon KrF Stepper & Scanner and TEL Clean track were used. Investigation was carried out on the defect formulation on both Acetal and ESCAP type of photoresist while elemental analysis was done by Atomic Force Microscope (AFM) & Auger Electron Spectroscopy (AES). Result indicated that both BARC and photoresist induce this UFO defect; total defect quantity is related with Post Exposure Bake (PEB) condition. Based on the elemental analysis and process-split test, we can conclude that this defect is caused by lack of acid amount and low diffusivity which is related to PAG (Photo Acid Generator) and TAG (Thermal Acid Generator) in KrF photoresist and BARC material. By optimizing photoresist bake condition, this UFO defect as well as other related defect such as Satellite defect could be eliminated.

  14. A note on glN type-I integrable defects

    International Nuclear Information System (INIS)

    Doikou, Anastasia

    2014-01-01

    Type-I quantum defects are considered in the context of the gl N spin chain. The type-I defects are associated with the generalized harmonic oscillator algebra, and the chosen defect matrix is that of the vector nonlinear Schrödinger (NLS) model. The transmission matrices relevant to this particular type of defects are computed via the Bethe ansatz methodology. (paper)

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

    International Nuclear Information System (INIS)

    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

  16. Kinetic Line Voronoi Operations and Their Reversibility

    DEFF Research Database (Denmark)

    Mioc, Darka; Anton, François; Gold, Christopher

    2010-01-01

    In Geographic Information Systems the reversibility of map update operations has not been explored yet. In this paper we are using the Voronoi based Quad-edge data structure to define reversible map update operations. The reversibility of the map operations has been formalised at the lowest level...... mechanisms and dynamic map visualisations. In order to use the reversibility within the kinetic Voronoi diagram of points and open oriented line segments, we need to assure that reversing the map commands will produce exactly the changes in the map equivalent to the previous map states. To prove...... that reversing the map update operations produces the exact reverse changes, we show an isomorphism between the set of complex operations on the kinetic Voronoi diagram of points and open oriented line segments and the sets of numbers of new / deleted Voronoi regions induced by these operations, and its...

  17. Effects of mass defect in atomic clocks

    Science.gov (United States)

    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..

  18. Research In Diagnosing Bearing Defects From Vibrations

    Science.gov (United States)

    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. New fundamental defects in a-SiO2

    International Nuclear Information System (INIS)

    Karna, S.P.; Kurtz, H.A.; Shedd, W.M.; Pugh, R.D.; Singaraju, B.K.

    1999-01-01

    Throughout the three decades of research into radiation-induced degradation of metal-oxide-semiconductor (MOS) devices, investigators understood that point defects in the Si-SiO 2 structure (localized deviations from stoichiometrically pure Si and SiO 2 ) are responsible for many observed anomalies. Basic research in this area has progressed along two tracks: (i) differentiating the anomalies based upon subtle differences in their characteristic behavior, and (ii) precise description of the defects responsible for the anomalous behavior. These two research tracks are complementary since often a discovery in one area provides insight and ultimately leads to discoveries in the other. Here, the atomic structure and spin properties of two previously undescribed amorphous silicon dioxide fundamental point defects have been characterized for the first time by ab initio quantum mechanical calculations. Both defects are electrically neutral trivalent silicon centers in the oxide. One of the defects, the X-center, is determined to have an O 2 Sitriple b ondSi ↑ atomic structure. The other defect, called the Y-center, is found to have an OSi 2 triple b ondSi ↑ structure. Calculated electronic and electrical properties of the new defect centers are consistent with the published characteristics of the oxide switching trap or border trap precursors

  20. The role of defects in laser damage of multilayer coatings

    International Nuclear Information System (INIS)

    Kozlowski, M.R.; Chow, R.

    1993-01-01

    Laser induced damage to optical coatings is generally a localized phenomenon associated with coating defects. The most common of the defect types are the well-known nodule defect. This paper reviews the use of experiments and modeling to understand the formation of these defects and their interaction with laser light. Of particular interest are efforts to identify which defects are most susceptible to laser damage. Also discussed are possible methods for stabilizing these defects (laser conditioning) or preventing their initiation (source stabilization, spatter particle trapping)