Science.gov

Sample records for a-center defect complex

  1. Invisible defects in complex crystals

    SciTech Connect

    Longhi, Stefano, E-mail: stefano.longhi@fisi.polimi.it; Della Valle, Giuseppe

    2013-07-15

    We show that invisible localized defects, i.e. defects that cannot be detected by an outside observer, can be realized in a crystal with an engineered imaginary potential at the defect site. The invisible defects are synthesized by means of supersymmetric (Darboux) transformations of an ordinary crystal using band-edge wavefunctions to construct the superpotential. The complex crystal has an entire real-valued energy spectrum and Bragg scattering is not influenced by the defects. An example of complex crystal synthesis is presented for the Mathieu potential. -- Highlights: •We show the existence of invisible localized defects in complex crystals. •They turn out tomore » be fully invisible to Bloch waves belonging to any lattice band. •An example of invisible defect is presented for a PT-symmetric Mathieu crystal.« less

  2. Bioprosthetics and repair of complex aerodigestive defects

    PubMed Central

    Udelsman, Brooks; Mathisen, Douglas J.

    2018-01-01

    Aerodigestive defects involving the trachea, bronchi and esophagus are a result of prolonged intubation, operative complications, congenital defects, trauma, radiation and neoplastic disease. The vast majority of these defects may be repaired primarily. Rarely, due the size of the defect, underlying complexity, or unfavorable patient characteristics, primary repair is not possible. One alternative to primary repair is bioprosthetic repair. Materials such as acellular dermal matrix and aortic homograft have been used in a variety of applications, including closure of tracheal, bronchial and esophageal defects. Herein, we review the use of bioprosthetics in the repair of aerodigestive defects, along with the unique advantages and disadvantages of these repairs. PMID:29707507

  3. Pectoralis major muscle defect and Poland complex.

    PubMed

    Castilla, E E; Paz, J E; Orioli, I M

    1979-01-01

    Pectoralis major muscle defect (PMD) was diagnosed in 27 infants from a series of 599,109 live births in South America (1/22,189). In all 27 cases the PMD was unilateral, mainly affecting the right side (20/27), and there were more male (19/27) than female cases. No familial cases and no parental consanguinity were recorded. A positive correlation was observed between PMD and sex hormone intake and vaginal bleeding in the first trimester of pregnancy. In 12 (1/49,925) of the 27 PMD cases hypoplasia and/or syndactyly of the ipsilateral hand was also diagnosed. The index-middle interdigital space was affected in all 11 cases with symbrachydactyly. Additional congenital anomalies were observed in 4/27 cases, and they were: hemangiomas, hypospadias, and clubfeet. Poland complex (12 cases), isolated PMD (15 cases), and isolated symbrachydactyly (18 cases), showed a similar pattern for symmetry, sidedness, syndactyly type, and sex ratio.

  4. Influence of oxygen-vacancy complex /A center/ on piezoresistance of n-type silicon.

    NASA Technical Reports Server (NTRS)

    Littlejohn, M. A.; Loggins, C. D., Jr.

    1972-01-01

    Changes in both magnitude and temperature dependence of the piezoresistance of electron-irradiated n-type silicon, induced by the latter's oxygen-vacancy complex (A center), are shown to be due to the fact that the presence of the A center causes the total conduction-band electron concentration to change with an applied stress. This change in electron concentration leads to an additional piezoresistance contribution that is expected to be important in certain many-valley semiconductors. This offers the possibility of tailoring the thermal variations of semiconductor mechanical sensors to more desirable values over limited temperature ranges.

  5. Impurity-defect complexes in non-implanted aluminum

    NASA Astrophysics Data System (ADS)

    Pedersen, F. T.; Grann, H.; Weyer, G.

    1986-02-01

    The formation of impurity-defect complexes in ion-implanted aluminum has been studied in the temperature interval 100 400K. Radioactive119In isotopes have been implanted. Mössbauer spectra have been measured for the 24 keV γ-radiation emitted after the decay to119Sn. The spectra could be analysed satisfactorily with two lines, one of which is known to be due to substitutional Sn. A second line, which has a higher isomer shift and lower Debye temperature, is tentatively assigned to vacancy-associated Sn, formed by trapping of thermally mobile (multi-)vacancies. Comparison to similar DPAC experiments suggests that cubic Sn-V4 complexes are formed. Some indication (˜15%) for an athermal formation of impurity defects below 175K is obtained.

  6. The Complex Genetic Basis of Congenital Heart Defects

    PubMed Central

    Akhirome, Ehiole; Walton, Nephi A.; Nogee, Julie M.; Jay, Patrick Y.

    2017-01-01

    Twenty years ago, chromosomal abnormalities were the only identifiable genetic causes of a small fraction of congenital heart defects (CHD). Today, a de novo or inherited genetic abnormality can be identified as pathogenic in one-third of cases. We refer to them here as monogenic causes, insofar as the genetic abnormality has a readily detectable, large effect. What explains the other two-thirds? This review considers a complex genetic basis. That is, a combination of genetic mutations or variants that individually may have little or no detectable effect contribute to the pathogenesis of a heart defect. Genes in the embryo that act directly in cardiac developmental pathways have received the most attention, but genes in the mother that establish the gestational milieu via pathways related to metabolism and aging also have an effect. A growing body of evidence highlights the pathogenic significance of genetic interactions in the embryo and maternal effects that have a genetic basis. The investigation of CHD as guided by a complex genetic model could help estimate risk more precisely and logically lead to a means of prevention. PMID:28381817

  7. Functional reconstruction of complex tendo Achilles defect by free latissimus dorsi muscle flap

    PubMed Central

    Upadhyaya, Divya N.; Khanna, Vaibhav; Kohli, Romesh; Tulsi, Satendar P. S.; Garg, Sandeep

    2012-01-01

    Managing the complex tendo Achilles defect involves reconstructing the Achilles tendon as well as providing soft tissue cover to the heel area. The advent of microsurgery has revolutionised the reconstruction of this difficult defect providing a number of options to the reconstructive surgeon. We present a case of complex tendo Achilles defect reconstructed by the latissimus dorsi free flap. PMID:23450740

  8. Energetics and Defect Interactions of Complex Oxides for Energy Applications

    NASA Astrophysics Data System (ADS)

    Solomon, Jonathan Michael

    The goal of this dissertation is to employ computational methods to gain greater insights into the energetics and defect interactions of complex oxides that are relevant for today's energy challenges. To achieve this goal, the development of novel computational methodologies are required to handle complex systems, including systems containing nearly 650 ions and systems with tens of thousands of possible atomic configurations. The systems that are investigated in this dissertation are aliovalently doped lanthanum orthophosphate (LaPO4) due to its potential application as a proton conducting electrolyte for intermediate temperature fuel cells, and aliovalently doped uranium dioxide (UO2) due to its importance in nuclear fuel performance and disposal. First we undertake density-functional-theory (DFT) calculations on the relative energetics of pyrophosphate defects and protons in LaPO4, including their binding with divalent dopant cations. In particular, for supercell calculations with 1.85 mol% Sr doping, we investigate the dopant-binding energies for pyrophosphate defects to be 0.37 eV, which is comparable to the value of 0.34 eV calculated for proton-dopant binding energies in the same system. These results establish that dopant-defect interactions further stabilize proton incorporation, with the hydration enthalpies when the dopants are nearest and furthest from the protons and pyrophosphate defects being -1.66 eV and -1.37 eV, respectively. Even though our calculations show that dopant binding enhances the enthalpic favorability of proton incorporation, they also suggest that such binding is likely to substantially lower the kinetic rate of hydrolysis of pyrophosphate defects. We then shift our focus to solid solutions of fluorite-structured UO 2 with trivalent rare earth fission product cations (M3+=Y, La) using a combination of ionic pair potential and DFT based methods. Calculated enthalpies of formation with respect to constituent oxides show higher

  9. Fumonisins, Tortillas and Neural Tube Defects: Untangling a Complex Issue

    USDA-ARS?s Scientific Manuscript database

    Fumonisin mycotoxins are found in corn and corn-based foods. Fumonisin B1 (FB1), the most common, disrupts sphingolipid metabolism thereby causing species-specific diseases in animals that include cancer in rodents and (birth) neural tube defects (NTD) in LM/Bc mice. Fumonisins’ affect on human heal...

  10. Complex cardiac defects after ethanol exposure during discrete cardiogenic events in zebrafish: Prevention with folic acid

    PubMed Central

    Sarmah, Swapnalee; Marrs, James A.

    2014-01-01

    BACKGROUND Fetal alcohol spectrum disorder (FASD) describes a range of birth defects including various congenital heart defects (CHDs). Mechanisms of FASD-associated CHDs are not understood. Whether alcohol interferes with a single critical event or with multiple events in heart formation is not known. RESULTS Our zebrafish embryo experiments showed that ethanol interrupts different cardiac regulatory networks and perturbed multiple steps of cardiogenesis (specification, myocardial migration, looping, chamber morphogenesis and endocardial cushion formation). Ethanol exposure during gastrulation until cardiac specification or during myocardial midline migration did not produce severe or persistent heart development defects. However, exposure comprising gastrulation until myocardial precursor midline fusion or during heart patterning stages produced aberrant heart looping and defective endocardial cushions. Continuous exposure during entire cardiogenesis produced complex cardiac defects leading to severely defective myocardium, endocardium, and endocardial cushions. Supplementation of retinoic acid with ethanol partially rescued early heart developmental defects, but the endocardial cushions did not form correctly. In contrast, supplementation of folic acid rescued normal heart development, including the endocardial cushions. CONCLUSIONS Our results indicate that ethanol exposure interrupted divergent cardiac morphogenesis events causing heart defects. Folic acid supplementation was effective in preventing a wide spectrum of ethanol-induced heart developmental defects. PMID:23832875

  11. Defect-mediated spatial complexity and chaos in a phase-conjugate resonator

    NASA Technical Reports Server (NTRS)

    Indebetouw, Guy; Liu, Siuying R.

    1992-01-01

    We have studied the spatiotemporal dynamics of a phase-conjugate resonator. The cavity Fresnel number is used to vary the degree of transverse confinement of the system. The generation and subsequent motion of the phase defects in the wave front are seen to mediate the system's dynamics. The number of defects and the complexity of their motion increases as the confinement is relaxed, leading the system through a sequence of bifurcations and eventually to chaos.

  12. Rapid screening for nuclear genes mutations in isolated respiratory chain complex I defects.

    PubMed

    Pagniez-Mammeri, Hélène; Lombes, Anne; Brivet, Michèle; Ogier-de Baulny, Hélène; Landrieu, Pierre; Legrand, Alain; Slama, Abdelhamid

    2009-04-01

    Complex I or reduced nicotinamide adenine dinucleotide (NADH): ubiquinone oxydoreductase deficiency is the most common cause of respiratory chain defects. Molecular bases of complex I deficiencies are rarely identified because of the dual genetic origin of this multi-enzymatic complex (nuclear DNA and mitochondrial DNA) and the lack of phenotype-genotype correlation. We used a rapid method to screen patients with isolated complex I deficiencies for nuclear genes mutations by Surveyor nuclease digestion of cDNAs. Eight complex I nuclear genes, among the most frequently mutated (NDUFS1, NDUFS2, NDUFS3, NDUFS4, NDUFS7, NDUFS8, NDUFV1 and NDUFV2), were studied in 22 cDNA fragments spanning their coding sequences in 8 patients with a biochemically proved complex I deficiency. Single nucleotide polymorphisms and missense mutations were detected in 18.7% of the cDNA fragments by Surveyor nuclease treatment. Molecular defects were detected in 3 patients. Surveyor nuclease screening is a reliable method for genotyping nuclear complex I deficiencies, easy to interpret, and limits the number of sequence reactions. Its use will enhance the possibility of prenatal diagnosis and help us for a better understanding of complex I molecular defects.

  13. Reconstruction of Complex Facial Defects Using Cervical Expanded Flap Prefabricated by Temporoparietal Fascia Flap.

    PubMed

    Zhang, Ling; Yang, Qinghua; Jiang, Haiyue; Liu, Ge; Huang, Wanlu; Dong, Weiwei

    2015-09-01

    Reconstruction of complex facial defects using cervical expanded flap prefabricated by temporoparietal fascia flap. Complex facial defects are required to restore not only function but also aesthetic appearance, so it is vital challenge for plastic surgeons. Skin grafts and traditional flap transfer cannot meet the reconstructive requirements of color and texture with recipient. The purpose of this sturdy is to create an expanded prefabricated temporoparietal fascia flap to repair complex facial defects. Two patients suffered severe burns on the face underwent complex facial resurfacing with prefabricated cervical flap. The vasculature of prefabricated flap, including the superficial temporal vessel and surrounding fascia, was used as the vascular carrier. The temporoparietal fascia flap was sutured underneath the cervical subcutaneous tissue, and expansion was begun in postoperative 1 week. After 4 to 6 months of expansion, the expander was removed, facial scars were excised, and cervical prefabricated flap was elevated and transferred to repair the complex facial defects. Two complex facial defects were repaired successfully by prefabricated temporoparietal fascia flap, and prefabricated flaps survived completely. On account of donor site's skin was thinner and expanded too fast, 1 expanded skin flap was rupture during expansion, but necrosis was not occurred after the 2nd operation. Venous congestion was observed in 1 patient, but after dressing, flap necrosis was not happened. Donor site was closed primarily. Postoperative follow-up 6 months, the color, texture of prefabricated flap was well-matched with facial skin. This method of expanded prefabricated flap may provide a reliable solution to the complex facial resurfacing.

  14. Propeller facial artery perforator flap as first reconstructive option for nasolabial and perinasal complex defects.

    PubMed

    Ruiz-Moya, A; Lagares-Borrego, A; Infante-Cossío, P

    2015-04-01

    Facial cutaneous oncological pathology often involves more than one esthetic unit due to their close boundaries. The reconstruction of both the nasolabial and perinasal regions may be especially complex and challenging for the surgeon. Traditionally, these defects have been reconstructed with local random flaps based on the vascularization provided by the superficial musculoaponeurotic system. In this article, we present our experience in the reconstruction of the aforementioned defects using the propeller facial artery perforator (FAP) flap. A propeller FAP flap was performed for reconstruction in 12 patients with nasolabial or perinasal complex defects after tumoral resection between the years 2011 and 2013. The flap was designed parallel to the nasolabial fold in all cases for achieving direct closure and an aesthetically pleasing outcome. In one of the cases, a paramedian forehead flap was performed simultaneously. Nine patients healed uneventfully, with good functional and esthetic outcomes. One of the flaps developed partial necrosis of the distal end, and another developed temporary postoperative venous congestion, lymphedema, and, finally, trapdoor deformity. The latter complication also occurred in one more flap. The propeller FAP flap is reliable and versatile, with few complications, and it is especially useful when reconstructing complex defects that involve the nasolabial and perinasal regions; therefore, it should be considered as one of the first reconstructive options for the described defects. Copyright © 2014 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  15. Defect states of complexes involving a vacancy on the boron site in boronitrene

    NASA Astrophysics Data System (ADS)

    Ngwenya, T. B.; Ukpong, A. M.; Chetty, N.

    2011-12-01

    First principles calculations have been performed to investigate the ground state properties of freestanding monolayer hexagonal boronitrene (h-BN). We have considered monolayers that contain native point defects and their complexes, which form when the point defects bind with the boron vacancy on the nearest-neighbor position. The changes in the electronic structure are analyzed to show the extent of localization of the defect-induced midgap states. The variations in formation energies suggest that defective h-BN monolayers that contain carbon substitutional impurities are the most stable structures, irrespective of the changes in growth conditions. The high energies of formation of the boron vacancy complexes suggest that they are less stable, and their creation by ion bombardment would require high-energy ions compared to point defects. Using the relative positions of the derived midgap levels for the double vacancy complex, it is shown that the quasi-donor-acceptor pair interpretation of optical transitions is consistent with stimulated transitions between electron and hole states in boronitrene.

  16. Defect Complex Effect in Nb Doped TiO2 Ceramics with Colossal Permittivity

    NASA Astrophysics Data System (ADS)

    Li, Fuchao; Shang, Baoqiang; Liang, Pengfei; Wei, Lingling; Yang, Zupei

    2016-10-01

    Donor-doped Nb x Ti1- x O2 ( x = 1%, 2%, 4%, 6%, and 8%) ceramics with giant permittivity (>104) and a very low dielectric loss (˜0.05) were sintered under flowing N2 at 1400°C for 10 h. By increasing Nb doping concentration, two different dielectric responses were evidenced in the frequency dependence of dielectric properties of Nb doped TiO2 ceramics, which corresponded to the space charge polarization and the electron-pinned defect-dipoles effect, respectively. Especially, combined with the x-ray photoelectron spectroscopy results, the electron-pinned defect-dipoles induced by the 2({Nb}^{5 + } )_{{Ti}}^{ bullet } to 4({Ti}^{3 + } )^'_{{Ti}} leftarrow {V}_{{o}}^{ bullet bullet } defect complex were further confirmed to give rise to both their high ɛr and low tan δ in the high frequency range for the Nb x Ti1- x O2 ceramics with x > 4%.

  17. Towards Improved Finite Element Modelling of the Interaction of Elastic Waves with Complex Defect Geometries

    NASA Astrophysics Data System (ADS)

    Rajagopal, P.; Drozdz, M.; Lowe, M. J. S.

    2009-03-01

    A solution to the problem of improving the finite element (FE) modeling of elastic wave-defect interaction is sought by reconsidering the conventional opinion on meshing strategy. The standard approach using uniform square elements imposes severe limitations in representing complex defect outlines but this is thought to improve when the mesh is made finer. Free meshing algorithms available widely in commercial packages of late can cope with difficult features well but they are thought to cause scattering by the irregular mesh itself. This paper examines whether the benefits offered by free meshing in representing defects better outweigh the inaccuracies due to mesh scattering. If using the standard mesh, the questions whether mesh refinement leads to improved results and whether a practical strategy can be constructed are considered.

  18. Enhanced Mass Defect Filtering To Simplify and Classify Complex Mixtures of Lignin Degradation Products.

    PubMed

    Dier, Tobias K F; Egele, Kerstin; Fossog, Verlaine; Hempelmann, Rolf; Volmer, Dietrich A

    2016-01-19

    High resolution mass spectrometry was utilized to study the highly complex product mixtures resulting from electrochemical breakdown of lignin. As most of the chemical structures of the degradation products were unknown, enhanced mass defect filtering techniques were implemented to simplify the characterization of the mixtures. It was shown that the implemented ionization techniques had a major impact on the range of detectable breakdown products, with atmospheric pressure photoionization in negative ionization mode providing the widest coverage in our experiments. Different modified Kendrick mass plots were used as a basis for mass defect filtering, where Kendrick mass defect and the mass defect of the lignin-specific guaiacol (C7H7O2) monomeric unit were utilized, readily allowing class assignments independent of the oligomeric state of the product. The enhanced mass defect filtering strategy therefore provided rapid characterization of the sample composition. In addition, the structural similarities between the compounds within a degradation sequence were determined by comparison to a tentatively identified product of this compound series. In general, our analyses revealed that primarily breakdown products with low oxygen content were formed under electrochemical conditions using protic ionic liquids as solvent for lignin.

  19. Mitochondrial respiratory chain Complex I defects in Fanconi anemia complementation group A.

    PubMed

    Ravera, Silvia; Vaccaro, Daniele; Cuccarolo, Paola; Columbaro, Marta; Capanni, Cristina; Bartolucci, Martina; Panfoli, Isabella; Morelli, Alessandro; Dufour, Carlo; Cappelli, Enrico; Degan, Paolo

    2013-10-01

    Fanconi anemia (FA) is a rare and complex inherited blood disorder of the child. At least 15 genes are associated with the disease. The highest frequency of mutations belongs to groups A, C and G. Genetic instability and cytokine hypersensitivity support the selection of leukemic over non-leukemic stem cells. FA cellular phenotype is characterized by alterations in red-ox state, mitochondrial functionality and energy metabolism as reported in the past however a clear picture of the altered biochemical phenotype in FA is still elusive and the final biochemical defect(s) still unknown. Here we report an analysis of the respiratory fluxes in FANCA primary fibroblasts, lymphocytes and lymphoblasts. FANCA mutants show defective respiration through Complex I, diminished ATP production and metabolic sufferance with an increased AMP/ATP ratio. Respiration in FANCC mutants is normal. Treatment with N-acetyl-cysteine (NAC) restores oxygen consumption to normal level. Defective respiration in FANCA mutants appear correlated with the FA pro-oxidative phenotype which is consistent with the altered morphology of FANCA mitochondria. Electron microscopy measures indeed show profound alterations in mitochondrial ultrastructure and shape. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  20. The first defective extended chromium atom chain complex with amine ligand containing naphthyridine and pyrazine

    NASA Astrophysics Data System (ADS)

    Wang, Wen-Zhen; Geng, Shu-Bo; Liu, Shuang; Zhao, Dan; Jia, Xin-Gang; Wei, Hai-Long; Ismayilov, Rayyat H.; Yeh, Chen-Yu; Lee, Gene-Hsiang; Peng, Shie-Ming

    2017-06-01

    Through a pyrazine and naphthyridine-containing diamino ligand, N2,N7-di(pyrazin-2-yl)-1,8-naphthyridine-2,7-diamine (H2dpznda), defective extended metal atom chain complexes with one chromium(II) metal absent in centre, [Cr5(μ5-dpznda)4Cl2] (1) and [Cr5(μ5-dpznda)4(NCS)2] (2) were obtained. An electrochemistry research showed that the pentachromium(II) complexes were quite resistant to reduction although accessible to oxidation, with two reversible redox couples at E1/2 = +0.59 and +0.30 V.

  1. Defect chaos and bursts: hexagonal rotating convection and the complex Ginzburg-Landau equation.

    PubMed

    Madruga, Santiago; Riecke, Hermann; Pesch, Werner

    2006-02-24

    We employ numerical computations of the full Navier-Stokes equations to investigate non-Boussinesq convection in a rotating system using water as the working fluid. We identify two regimes. For weak non-Boussinesq effects the Hopf bifurcation from steady to oscillating (whirling) hexagons is supercritical and typical states exhibit defect chaos that is systematically described by the cubic complex Ginzburg-Landau equation. For stronger non-Boussinesq effects the Hopf bifurcation becomes subcritical and the oscillations exhibit localized chaotic bursting, which is modeled by a quintic complex Ginzburg-Landau equation.

  2. Dynamics of Defects and Dopants in Complex Systems: Si and Oxide Surfaces and Interfaces

    NASA Astrophysics Data System (ADS)

    Kirichenko, Taras; Yu, Decai; Banarjee, Sanjay; Hwang, Gyeong

    2004-10-01

    Fabrication of forthcoming nanometer scale electronic devices faces many difficulties including formation of extremely shallow and highly doped junctions. At present, ultra-low-energy ion implantation followed by high-temperature thermal annealing is most widely used to fabricate such ultra-shallow junctions. In the process, a great challenge lies in achieving precise control of redistribution and electrical activation of dopant impurities. Native defects (such as vacancies and interstitials) generated during implantation are known to be mainly responsible for the TED and also influence significantly the electrical activation/deactivation. Defect-dopant dynamics is rather well understood in crystalline Si and SiO2. However, little is known about their diffusion and annihilation (or precipitation) at the surfaces and interfaces, despite its growing importance in determining junction profiles as device dimensions get smaller. In this talk, we will present our density functional theory calculation results on the atomic and electronic structure and dynamical behavior of native defects and dopant-defect complexes in disordered/strained Si and oxide systems, such as i) clean and absorbent-modified Si(100) surface and subsurface layers, ii) amorphous-crystalline Si interfaces and iii) amorphous SiO2/Si interfaces. The fundamental understanding and data is essential in developing a comprehensive kinetic model for junction formation, which would contribute greatly in improving current process technologies.

  3. Defect control of conventional and anomalous electron transport at complex oxide interfaces

    DOE PAGES

    Gunkel, F.; Bell, Chris; Inoue, Hisashi; ...

    2016-08-30

    Using low-temperature electrical measurements, the interrelation between electron transport, magnetic properties, and ionic defect structure in complex oxide interface systems is investigated, focusing on NdGaO 3/SrTiO 3 (100) interfaces. Field-dependent Hall characteristics (2–300 K) are obtained for samples grown at various growth pressures. In addition to multiple electron transport, interfacial magnetism is tracked exploiting the anomalous Hall effect (AHE). These two properties both contribute to a nonlinearity in the field dependence of the Hall resistance, with multiple carrier conduction evident below 30 K and AHE at temperatures ≲10 K. Considering these two sources of nonlinearity, we suggest a phenomenological modelmore » capturing the complex field dependence of the Hall characteristics in the low-temperature regime. Our model allows the extraction of the conventional transport parameters and a qualitative analysis of the magnetization. The electron mobility is found to decrease systematically with increasing growth pressure. This suggests dominant electron scattering by acceptor-type strontium vacancies incorporated during growth. The AHE scales with growth pressure. In conclusion, the most pronounced AHE is found at increased growth pressure and, thus, in the most defective, low-mobility samples, indicating a correlation between transport, magnetism, and cation defect concentration.« less

  4. Tuning to the band gap by complex defects engineering: insights from hybrid functional calculations in CuInS2

    NASA Astrophysics Data System (ADS)

    Yang, Pei; Shi, Li-Jie; Zhang, Jian-Min; Liu, Gui-Bin; Yang, Shengyuan A.; Guo, Wei; Yao, Yugui

    2018-01-01

    Tuning band gaps of semiconductors in terms of defect control is essential for the optical and electronic properties of photon emission or photon harvesting devices. By using first-principles calculations, we study the stability condition of bulk CuInS2 and formation energies of point and complex defects in CuInS2 with hybrid exchange-correlation functionals. We find that at Cu-rich and In-poor conditions, 2Cui  +  CuIn is the main complex defect, while InCu  +  2VCu is the main complex defect at In-rich and Cu-poor conditions. Such stable complex defects provide the feasibility of tuning band gaps by varying the [Cu]/[In] molar ratios. These results present how the off-stoichiometry CuInS2 crystal structures, and electronic and optical properties can be optimized by tuning the [Cu]/[In] ratio and Fermi level, and highlight the importance of complex defects in achieving better photoelectric performance in CuInS2. Such band gap tuning in terms of complex defect engineering is a general approach and thus applicable to other photo-harvest or light-emission semiconductors.

  5. Monti's procedure as an alternative technique in complex urethral distraction defect.

    PubMed

    Hosseini, Jalil; Kaviani, Ali; Mazloomfard, Mohammad M; Golshan, Ali R

    2010-01-01

    Pelvic fracture urethral distraction defect is usually managed by the end to end anastomotic urethroplasty. Surgical repair of those patients with post-traumatic complex posterior urethral defects, who have undergone failed previous surgical treatments, remains one of the most challenging problems in urology. Appendix urinary diversion could be used in such cases. However, the appendix tissue is not always usable. We report our experience on management of patients with long urethral defect with history of one or more failed urethroplasties by Monti channel urinary diversion. From 2001 to 2007, we evaluated data from 8 male patients aged 28 to 76 years (mean age 42.5) in whom the Monti technique was performed. All cases had history of posterior urethral defect with one or more failed procedures for urethral reconstruction including urethroplasty. A 2 to 2.5 cm segment of ileum, which had a suitable blood supply, was cut. After the re-anastomosis of the ileum, we closed the opened ileum transversely surrounding a 14-16 Fr urethral catheter using running Vicryl sutures. The newly built tube was used as an appendix during diversion. All patients performed catheterization through the conduit without difficulty and stomal stenosis. Mild stomal incontinence occurred in one patient in the supine position who became continent after adjustment of the catheterization intervals. There was no dehiscence, necrosis or perforation of the tube. Based on our data, Monti's procedure seems to be a valuable technique in patients with very long complicated urethral defect who cannot be managed with routine urethroplastic techniques.

  6. A new custom made bioceramic implant for the repair of large and complex craniofacial bone defects.

    PubMed

    Brie, Joël; Chartier, Thierry; Chaput, Christophe; Delage, Cyrille; Pradeau, Benjamin; Caire, François; Boncoeur, Marie-Paule; Moreau, Jean-Jacques

    2013-07-01

    Neurosurgery and Maxillofacial Surgery Departments of Limoges University Hospital Centre have developed a new concept of a custom made ceramic implant in hydroxyapatite (HA) for the reconstruction of large and complex craniofacial bone defects (more than 25 cm(2)). The manufacturing process of the implants used a stereolithography technique that produces implants with three-dimensional shapes derived directly from the scan file of the patient's skull without moulding or machining. Eight patients received 8 implants between 2005 and 2008. The surgical procedure is simple and fast. The post-operative follow-up was 12 months. No major complications (infection or fracture of the implant) were observed. The cosmetic result was considered satisfactory by both patients and surgeons. These new implants are well suited for reconstruction of large craniofacial bone defects (greater than 25 cm(2)) in adults and children over 8 years. Copyright © 2012 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  7. Carbon as a source for yellow luminescence in GaN: Isolated C{sub N} defect or its complexes

    SciTech Connect

    Christenson, Sayre G.; Xie, Weiyu; Sun, Y. Y., E-mail: suny4@rpi.edu

    2015-10-07

    We study three carbon defects in GaN, isolated C{sub N} and its two complexes with donors C{sub N}–O{sub N}, and C{sub N}–Si{sub Ga}, as a cause of the yellow luminescence using accurate hybrid density functional calculation, which includes the semi-core Ga 3d electrons as valence electrons and uses a larger 300-atom supercell. We show that the isolated C{sub N} defect yields good agreement with experiment on the photoluminescence (PL) peak position, zero-phonon line, and thermodynamic defect transition level. We find that the defect state of the complexes that is involved in the PL process is the same as that ofmore » the C{sub N} defect. The role of the positively charged donors (O{sub N} or Si{sub Ga}) next to C{sub N} is to blue-shift the PL peak. Therefore, the complexes cannot be responsible for the same PL peak as isolated C{sub N}. Our detailed balance analysis further suggests that under thermal equilibrium at typical growth temperature, the concentration of isolated C{sub N} defect is orders of magnitude higher than the defect complexes, which is a result of the small binding energy in these complexes.« less

  8. Utilisation of three-dimensional printed heart models for operative planning of complex congenital heart defects.

    PubMed

    Olejník, Peter; Nosal, Matej; Havran, Tomas; Furdova, Adriana; Cizmar, Maros; Slabej, Michal; Thurzo, Andrej; Vitovic, Pavol; Klvac, Martin; Acel, Tibor; Masura, Jozef

    2017-01-01

    To evaluate the accuracy of the three-dimensional (3D) printing of cardiovascular structures. To explore whether utilisation of 3D printed heart replicas can improve surgical and catheter interventional planning in patients with complex congenital heart defects. Between December 2014 and November 2015 we fabricated eight cardiovascular models based on computed tomography data in patients with complex spatial anatomical relationships of cardiovascular structures. A Bland-Altman analysis was used to assess the accuracy of 3D printing by comparing dimension measurements at analogous anatomical locations between the printed models and digital imagery data, as well as between printed models and in vivo surgical findings. The contribution of 3D printed heart models for perioperative planning improvement was evaluated in the four most representative patients. Bland-Altman analysis confirmed the high accuracy of 3D cardiovascular printing. Each printed model offered an improved spatial anatomical orientation of cardiovascular structures. Current 3D printers can produce authentic copies of patients` cardiovascular systems from computed tomography data. The use of 3D printed models can facilitate surgical or catheter interventional procedures in patients with complex congenital heart defects due to better preoperative planning and intraoperative orientation.

  9. Laparoscopic omentoplasty to support anastomotic urethroplasty in complex and redo pelvic fracture urethral defects.

    PubMed

    Kulkarni, Sanjay B; Barbagli, Guido; Joshi, Pankaj M; Hunter, Craig; Shahrour, Walid; Kulkarni, Jyotsna; Sansalone, Salvatore; Lazzeri, Massimo

    2015-05-01

    To test the hypothesis that a new surgical technique using elaborated perineal anastomotic urethroplasty combined with laparoscopic omentoplasty for patients with complex and prior failed pelvic fracture urethral defect repair was feasible, safe, and effective. We performed a prospective, observational, stage 2a study to observe treatment outcomes of combined perineal and laparoscopic approach for urethroplasty in patients with pelvic fracture urethral defect at a single center in Pune, India, between January 2012 and February 2013. Complex and redo patients with pelvic fracture urethral defect occurring after pelvic fracture urethral injury were included in the study. Anterior urethral strictures were excluded. The primary study outcome was the success rate of the surgical technique, and the secondary outcome was to evaluate feasibility and safety of the procedure. The clinical outcome was considered a failure when any postoperative instrumentation was needed. Fifteen male patients with a median age of 19 years were included in the study. Seven patients were adolescents (12-18 years) and 8 patients (53.3%) were adults (19-49 years). The mean number of prior urethroplasties was 1.8 (range, 1-3). All patients underwent elaborated bulbomembranous anastomosis using a perineal approach with inferior pubectomy combined with laparoscopic mobilization of the omentum into the perineum to envelope the anastomosis and to fill the perineal dead space. Of 15 patients, 14 (93.3%) were successful and 1 (6.6%) failed. One adolescent boy 14 years old developed a recurrent stricture 2 months after the procedure and was managed using internal urethrotomy. Median follow-up was 18 months (range, 13-24 months). Combining a laparoscopic omentoplasty to a membranobulbar anastomosis for complex and redo pelvic fracture urethral injury is successful, feasible, safe, and with minimal additional morbidity to the patient. The technique has the advantage of a perineal incision and the ability

  10. Loop quantum gravity simplicity constraint as surface defect in complex Chern-Simons theory

    NASA Astrophysics Data System (ADS)

    Han, Muxin; Huang, Zichang

    2017-05-01

    The simplicity constraint is studied in the context of four-dimensional spinfoam models with a cosmological constant. We find that the quantum simplicity constraint is realized as the two-dimensional surface defect in SL (2 ,C ) Chern-Simons theory in the construction of spinfoam amplitudes. By this realization of the simplicity constraint in Chern-Simons theory, we are able to construct the new spinfoam amplitude with a cosmological constant for an arbitrary simplicial complex (with many 4-simplices). The semiclassical asymptotics of the amplitude is shown to correctly reproduce the four-dimensional Einstein-Regge action with a cosmological constant term.

  11. Enhanced photoluminescence from single nitrogen-vacancy defects in nanodiamonds coated with phenol-ionic complexes.

    PubMed

    Bray, Kerem; Previdi, Rodolfo; Gibson, Brant C; Shimoni, Olga; Aharonovich, Igor

    2015-03-21

    Fluorescent nanodiamonds are attracting major attention in the field of bio-sensing and bio-labeling. In this work we demonstrate a robust approach to achieve an encapsulation of individual nanodiamonds with phenol-ionic complexes that enhance the photoluminescence from single nitrogen vacancy (NV) centers. We show that single NV centres in the coated nanodiamonds also exhibit shorter lifetimes, opening another channel for high resolution sensing. We propose that the nanodiamond encapsulation reduces the non-radiative decay pathways of the NV color centers. Our results provide a versatile and assessable way to enhance photoluminescence from nanodiamond defects that can be used in a variety of sensing and imaging applications.

  12. Perforator chimerism for the reconstruction of complex defects: A new chimeric free flap classification system.

    PubMed

    Kim, Jeong Tae; Kim, Youn Hwan; Ghanem, Ali M

    2015-11-01

    Complex defects present structural and functional challenges to reconstructive surgeons. When compared to multiple free flaps or staged reconstruction, the use of chimeric flaps to reconstruct such defects have many advantages such as reduced number of operative procedures and donor site morbidity as well as preservation of recipient vessels. With increased popularity of perforator flaps, chimeric flaps' harvest and design has benefited from 'perforator concept' towards more versatile and better reconstruction solutions. This article discusses perforator based chimeric flaps and presents a practice based classification system that incorporates the perforator flap concept into "Perforator Chimerism". The authors analyzed a variety of chimeric patterns used in 31 consecutive cases to present illustrative case series and their new classification system. Accordingly, chimeric flaps are classified into four types. Type I: Classical Chimerism, Type II: Anastomotic Chimerism, Type III: Perforator Chimerism and Type IV Mixed Chimerism. Types I on specific source vessel anatomy whilst Type II requires microvascular anastomosis to create the chimeric reconstructive solution. Type III chimeric flaps utilizes the perforator concept to raise two components of tissues without microvascular anastomosis between them. Type IV chimeric flaps are mixed type flaps comprising any combination of Types I to III. Incorporation of the perforator concept in planning and designing chimeric flaps has allowed safe, effective and aesthetically superior reconstruction of complex defects. The new classification system aids reconstructive surgeons and trainees to understand chimeric flaps design, facilitating effective incorporation of this important reconstructive technique into the armamentarium of the reconstruction toolbox. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  13. Enhanced photoluminescence from single nitrogen-vacancy defects in nanodiamonds coated with phenol-ionic complexes

    NASA Astrophysics Data System (ADS)

    Bray, Kerem; Previdi, Rodolfo; Gibson, Brant C.; Shimoni, Olga; Aharonovich, Igor

    2015-03-01

    Fluorescent nanodiamonds are attracting major attention in the field of bio-sensing and bio-labeling. In this work we demonstrate a robust approach to achieve an encapsulation of individual nanodiamonds with phenol-ionic complexes that enhance the photoluminescence from single nitrogen vacancy (NV) centers. We show that single NV centres in the coated nanodiamonds also exhibit shorter lifetimes, opening another channel for high resolution sensing. We propose that the nanodiamond encapsulation reduces the non-radiative decay pathways of the NV color centers. Our results provide a versatile and assessable way to enhance photoluminescence from nanodiamond defects that can be used in a variety of sensing and imaging applications.Fluorescent nanodiamonds are attracting major attention in the field of bio-sensing and bio-labeling. In this work we demonstrate a robust approach to achieve an encapsulation of individual nanodiamonds with phenol-ionic complexes that enhance the photoluminescence from single nitrogen vacancy (NV) centers. We show that single NV centres in the coated nanodiamonds also exhibit shorter lifetimes, opening another channel for high resolution sensing. We propose that the nanodiamond encapsulation reduces the non-radiative decay pathways of the NV color centers. Our results provide a versatile and assessable way to enhance photoluminescence from nanodiamond defects that can be used in a variety of sensing and imaging applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr07510b

  14. Adhesive complex coacervate inspired by the sandcastle worm as a sealant for fetoscopic defects

    NASA Astrophysics Data System (ADS)

    Kaur, Sarbjit

    Inspired by the Sandcastle Worm, biomimetic of the water-borne adhesive was developed by complex coacervation of the synthetic copolyelectrolytes, mimicking the chemistries of the worm glue. The developed underwater adhesive was designed for sealing fetal membranes after fetoscopic surgery in twin-to-twin transfusion syndrome (TTTS) and sealing neural tissue of a fetus in aminiotic sac for spina bifida condition. Complex coacervate with increased bond strength was created by entrapping polyethylene glycol diacrylate (PEG-dA) monomer within the cross-linked coacervate network. Maximum shear bond strength of ~ 1.2 MPa on aluminum substrates was reached. The monomer-filled coacervate had complex flow behavior, thickening at low shear rates and then thinning suddenly with a 16-fold drop in viscosity at shear rates near 6 s-1. The microscale structure of the complex coacervates resembled a three-dimensional porous network of interconnected tubules. This complex coacervate adhesive was used in vitro studies to mimic the uterine wall-fetal membrane interface using a water column with one end and sealed with human fetal membranes and poultry breast, and a defect was created with an 11 French trocar. The coacervate adhesive in conjunction with the multiphase adhesive was used to seal the defect. The sealant withstood an additional traction of 12 g for 30-60 minutes and turbulence of the water column without leakage of fluid or slippage. The adhesive is nontoxic when in direct contact with human fetal membranes in an organ culture setting. A stable complex coacervate adhesive for long-term use in TTTS and spina bifida application was developed by methacrylating the copolyelectrolytes. The methacrylated coacervate was crosslinked chemically for TTTS and by photopolymerization for spina bifida. Tunable mechanical properties of the adhesive were achieved by varying the methacrylation of the polymers. Varying the amine to phosphate (A/P) ratio in the coacervate formation

  15. [Subchondral drilling method combined with gum-bletilla complex to repair articular cartilage defects].

    PubMed

    Huang, Yong; Wang, Xin-Ling; Qiu, Heng; Xiao, Yi-Cheng; Wu, Zong-Hong; Xu, Jian

    2018-02-01

    Two types(A model and B model) of articular cartilage defect models were prepared by using adult New Zealand white rabbits. A model group was applied by drilling without through subchondral bone, whose right joint was repaired by composite scaffolds made by seed cell, gum-bletilla as well as Pluronic F-127, and left side was blank control. B model group was applied by subchondral drilling method, whose right joint was repaired by using composite scaffolds made by gum-bletilla and Pluronic F-127 without seed cells, and left side was blank control. Autogenous contrast was used in both model types. In addition, another group was applied with B model type rabbits, which was repaired with artificial complex material of Pluronic F-127 in both joint sides. 4, 12 and 24 weeks after operation, the animals were sacrificed and the samples were collected from repaired area for staining with HE, typeⅡcollagen immunohistochemical method, Alcian blue, and toluidine blue, and then were observed with optical microscope. Semi-quantitative scores were graded by referring to Wakitanis histological scoring standard to investigate the histomorphology of repaired tissue. Hyaline cartilage repairing was achieved in both Group A and Group B, with satisfactory results. There were no significant differences on repairing effects for articular cartilage defects between composite scaffolds made by seed cell, gum-bletilla and Pluronic F-127, and the composite scaffolds made by gum-bletilla and Pluronic F-127 without seed cell. Better repairing effects for articular cartilage defects were observed in groups with use of gum-bletilla, indicating that gum-bletilla is a vital part in composite scaffolds material. Copyright© by the Chinese Pharmaceutical Association.

  16. Leigh disease with brainstem involvement in complex I deficiency due to assembly factor NDUFAF2 defect.

    PubMed

    Herzer, M; Koch, J; Prokisch, H; Rodenburg, R; Rauscher, C; Radauer, W; Forstner, R; Pilz, P; Rolinski, B; Freisinger, P; Mayr, J A; Sperl, W

    2010-02-01

    Mitochondrial NADH: ubiquinone oxidoreductase (complex I) deficiency accounts for most defects in mitochondrial oxidative phosphorylation. Pathogenic mutations have been described in all 7 mitochondrial and 12 of the 38 nuclear encoded subunits as well as in assembly factors by interfering with the building of the mature enzyme complex within the inner mitochondrial membrane. We now describe a male patient with a novel homozygous stop mutation in the NDUFAF2 gene. The boy presented with severe apnoea and nystagmus. MRI showed brainstem lesions without involvement of basal ganglia and thalamus, plasma lactate was normal or close to normal. He died after a fulminate course within 2 months after the first crisis. Neuropathology verified Leigh disease. We give a synopsis with other reported patients. Within the clinical spectrum of Leigh disease, patients with mutations in NDUFAF2 present with a distinct clinical pattern with predominantly brainstem involvement on MRI. The diagnosis should not be missed in spite of the normal lactate and lack of thalamus and basal ganglia changes on brain MRI.

  17. Mineralization Induction of Gingival Fibroblasts and Construction of a Sandwich Tissue-Engineered Complex for Repairing Periodontal Defects

    PubMed Central

    Wu, Mingxuan; Zhang, Yanning; Liu, Huijuan; Dong, Fusheng

    2018-01-01

    Background The ideal healing technique for periodontal tissue defects would involve the functional regeneration of the alveolar bone, cementum, and periodontal ligament, with new periodontal attachment formation. In this study, gingival fibroblasts were induced and a “sandwich” tissue-engineered complex (a tissue-engineered periodontal membrane between 2 tissue-engineered mineralized membranes) was constructed to repair periodontal defects. We evaluated the effects of gingival fibroblasts used as seed cells on the repair of periodontal defects and periodontal regeneration. Material/Methods Primitively cultured gingival fibroblasts were seeded bilaterally on Bio-Gide collagen membrane (a tissue-engineered periodontal membrane) or unilaterally on small intestinal submucosa segments, and their mineralization was induced. A tissue-engineered sandwich was constructed, comprising the tissue-engineered periodontal membrane flanked by 2 mineralized membranes. Periodontal defects in premolar regions of Beagles were repaired using the tissue-engineered sandwich or periodontal membranes. Periodontal reconstruction was compared to normal and trauma controls 10 or 20 days postoperatively. Results Periodontal defects were completely repaired by the sandwich tissue-engineered complex, with intact new alveolar bone and cementum, and a new periodontal ligament, 10 days postoperatively. Conclusions The sandwich tissue-engineered complex can achieve ideal periodontal reconstruction rapidly. PMID:29470454

  18. Complex photonic lattices embedded with tailored intrinsic defects by a dynamically reconfigurable single step interferometric approach

    SciTech Connect

    Xavier, Jolly, E-mail: jolly.xavierp@physics.iitd.ac.in; Joseph, Joby, E-mail: joby@physics.iitd.ac.in

    2014-02-24

    We report sculptured diverse photonic lattices simultaneously embedded with intrinsic defects of tunable type, number, shape as well as position by a single-step dynamically reconfigurable fabrication approach based on a programmable phase spatial light modulator-assisted interference lithography. The presented results on controlled formation of intrinsic defects in periodic as well as transversely quasicrystallographic lattices, irrespective and independent of their designed lattice geometry, portray the flexibility and versatility of the approach. The defect-formation in photonic lattices is also experimentally analyzed. Further, we also demonstrate the feasibility of fabrication of such defects-embedded photonic lattices in a photoresist, aiming concrete integrated photonic applications.

  19. Application of Hydrogel in Reconstruction Surgery: Hydrogel/Fat Graft Complex Filler for Volume Reconstruction in Critical Sized Muscle Defects.

    PubMed

    Lui, Y F; Ip, W Y

    2016-01-01

    Autogenic fat graft usually suffers from degeneration and volume shrinkage in volume reconstruction applications. How to maintain graft viability and graft volume is an essential consideration in reconstruction therapies. In this presented investigation, a new fat graft transplantation method was developed aiming to improve long term graft viability and volume reconstruction effect by incorporation of hydrogel. The harvested fat graft is dissociated into small fragments and incorporated into a collagen based hydrogel to form a hydrogel/fat graft complex for volume reconstruction purpose. In vitro results indicate that the collagen based hydrogel can significantly improve the survivability of cells inside isolated graft. In a 6-month investigation on artificial created defect model, this hydrogel/fat graft complex filler has demonstrated the ability of promoting fat pad formation inside the targeted defect area. The newly generated fat pad can cover the whole defect and restore its original dimension in 6-month time point. Compared to simple fat transplantation, this hydrogel/fat graft complex system provides much improvement on long term volume restoration effect against degeneration and volume shrinkage. One notable effect is that there is continuous proliferation of adipose tissue throughout the 6-month period. In summary, the hydrogel/fat graft system presented in this investigation demonstrated a better and more significant effect on volume reconstruction in large sized volume defect than simple fat transplantation.

  20. Ab initio EPR parameters for dangling-bond defect complexes in silicon: Effect of Jahn-Teller distortion

    NASA Astrophysics Data System (ADS)

    Pfanner, Gernot; Freysoldt, Christoph; Neugebauer, Jörg; Gerstmann, Uwe

    2012-05-01

    A dangling bond (db) is an important point defect in silicon. It is realized in crystalline silicon by defect complexes of the monovacancy V with impurities. In this work, we present spin-polarized density-functional theory calculations of EPR parameters (g and hyperfine tensors) within the GIPAW formalism for two kinds of db defect complexes. The first class characterizes chemically saturated db systems, where three of the four dangling bonds of the isolated vacancy are saturated by hydrogen (VH3) or hydrogen and oxygen (hydrogen-oxygen complex, VOH). The second kind of db consists of systems with a Jahn-Teller distortion, where the vacancy includes either a substitutional phosphorus atom (the E center, VP) or a single hydrogen atom (VH). For all systems we obtain excellent agreement with available experimental data, and we are therefore able to quantify the effect of the Jahn-Teller distortion on the EPR parameters. Furthermore we study the influence of strain to obtain further insights into the structural and electronic characteristics of the considered defects.

  1. The two gap transitions in Ge1 -xSnx : Effect of non-substitutional complex defects

    NASA Astrophysics Data System (ADS)

    Querales-Flores, J. D.; Ventura, C. I.; Fuhr, J. D.; Barrio, R. A.

    2016-09-01

    The existence of non-substitutional β-Sn defects in Ge1 -xSnx alloys was confirmed by emission channeling experiments [Decoster et al., Phys. Rev. B 81, 155204 (2010)], which established that, although most Sn enters substitutionally (α-Sn) in the Ge lattice, a second significant fraction corresponds to the Sn-vacancy defect complex in the split-vacancy configuration (β-Sn), in agreement with our previous theoretical study [Ventura et al., Phys. Rev. B 79, 155202 (2009)]. Here, we present the electronic structure calculations for Ge1 -xSnx , including the substitutional α-Sn as well as the non-substitutional β-Sn defects. To include the presence of the non-substitutional complex defects in the electronic structure calculation for this multi-orbital alloy problem, we extended the approach for the purely substitutional alloy by Jenkins and Dow [Phys. Rev. B 36, 7994 (1987)]. We employed an effective substitutional two-site cluster equivalent to the real non-substitutional β-Sn defect, which was determined by a Green's functions calculation. We then calculated the electronic structure of the effective alloy purely in terms of substitutional defects, embedding the effective substitutional clusters in the lattice. Our results describe the two transitions of the fundamental gap of Ge1 -xSnx as a function of the total Sn-concentration: namely, from an indirect to a direct gap, first, and the metallization transition at a higher x. They also highlight the role of β-Sn in the reduction of the concentration range, which corresponds to the direct-gap phase of this alloy of interest for the optoelectronics applications.

  2. Infrared defect dynamics—Nitrogen-vacancy complexes in float zone grown silicon introduced by electron irradiation

    NASA Astrophysics Data System (ADS)

    Inoue, Naohisa; Kawamura, Yuichi

    2018-05-01

    The interaction of nitrogen and intrinsic point defects, vacancy (V) and self-interstitial (I), was examined by infrared absorption spectroscopy on the electron irradiated and post-annealed nitrogen doped float zone (FZ) silicon crystal. Various absorption lines were observed, at 551 cm-1 in as-grown samples, at 726 and 778 cm-1 in as-irradiated samples (Ir group), at 689 cm-1 after post-annealing at 400 °C and above (400 °C group), at 762 and 951 cm-1 after annealing at 600 °C (600 °C group), and at 714 cm-1 up to 800 °C (800 °C group). By irradiation, a part of N2 was changed into the Ir group. VN2 is the candidate for the origin of the Ir group. By the post annealing at 400 and 600 °C, a part of N2 and the Ir group were changed into the 400 °C group, to less extent at 600 °C. V2N2 is the candidate for the origin of the 400 °C group. By annealing at 600 °C, most of the Ir group turned into 400 °C and 600 °C groups. By annealing at 800 °C, N2 recovered almost completely, and most other complexes were not observed. Recently, lifetime degradation has been observed in the nitrogen doped FZ Si annealed at between 450 and 800 °C. The N-V interaction in the same temperature range revealed here will help to understand the lifetime degradation mechanism. The behavior of the 689 cm-1 line corresponded well to the lifetime degradation.

  3. Chimeric anterolateral thigh free flap for reconstruction of complex cranio-orbito-facial defects after skull base cancers resection.

    PubMed

    Cherubino, Mario; Turri-Zanoni, Mario; Battaglia, Paolo; Giudice, Marco; Pellegatta, Igor; Tamborini, Federico; Maggiulli, Francesca; Guzzetti, Luca; Di Giovanna, Danilo; Bignami, Maurizio; Calati, Carolina; Castelnuovo, Paolo; Valdatta, Luigi

    2017-01-01

    Complex cranio-orbito-facial defects after skull base cancers resection entail a functional and esthetic reconstruction. The introduction of endoscopic assisted techniques for excision surgery with the advances in reconstructive surgery and anesthesiology allowed to improve the management of such critical patients. We report a series of chimeric anterolateral thigh (ALT) flaps used to reconstruct complex cranio-orbital-facial defects after skull base surgery. A retrospective review of patients that underwent cranio-orbito-facial reconstruction using a chimeric ALT flap from March 2013 to October 2015 at a single tertiary care referral Institute was performed. All patients were affected by locally-advanced malignant tumor and the resulting defects involved the skull base in all cases. The ALT flaps were perforator-based flaps with different components: fascia, skin and muscle. The different flap territories had independent vascular supply and were independent of any physical interconnection except where linked by a common source vessel. Ten patients were included in the study. Three patients underwent adjuvant radiotherapy and to chemotherapy. The mean hospitalization time was 21 days (range, 8-24 days). One failure was observed. After a mean follow-up of 12.4 months, 3 patients died of the disease, 2 are alive with disease, while 5 patients (50%) are currently alive without evidence of disease. Chimeric ALT flap is a reliable and versatile reconstructive option for complex cranio-orbito-facial defects resulting from skull base surgery. The chimeric flap composed of different territories proved to be adequate for a patient-tailored three-dimensional reconstruction of the defects as well as able to resist to the postoperative adjuvant treatments. Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  4. Cor triatriatum dexter associated with atrial septal defect: Management in a complex clinical case.

    PubMed

    Sozzi, Fabiola B; Montanaro, Claudia; Bacà, Laura; Viani, Giacomo M; Zilocchi, Massimo; Canetta, Ciro; Meazza, Roberto; Pavone, Laura; Lombardi, Federico

    2017-11-01

    The coexistence of an atrial septal defect and a prominent eustachian valve is a rare congenital anomaly, rarely reported in literature. Differentiation between a giant eustachian valve and cor triatriatum dexter can be difficult. A case of a large atrial septal defect associated with cor triatriatum dexter diagnosed by echocardiography in an asymptomatic woman is reported. A watchful waiting strategy was adopted. © 2017, Wiley Periodicals, Inc.

  5. Gerbode defect and multivalvular dysfunction: Complex complications in adult congenital heart disease.

    PubMed

    Ruivo, Catarina; Guardado, Joana; Montenegro Sá, Fernando; Saraiva, Fátima; Antunes, Alexandre; Correia, Joana; Morais, João

    2017-07-01

    We report a clinical case of a 40-year-old male with surgically corrected congenital heart disease (CHD) 10 years earlier: closure of ostium primum, mitral annuloplasty, and aortic valve and root surgery. The patient was admitted with acute heart failure. Transesophageal echocardiography (TEE) revealed a dysmorphic and severely incompetent aortic valve, a partial tear of the mitral valve cleft repair and annuloplasty ring dehiscence. A true left ventricular-to-right atrial shunt confirmed a direct Gerbode defect. The authors aim to discuss the diagnostic challenge of adult CHD, namely the key role of TEE on septal defects and valve regurgitations description. © 2017, Wiley Periodicals, Inc.

  6. Lessons Learned from Delayed Versus Immediate Microsurgical Reconstruction of Complex Maxillectomy and Midfacial Defects: Experience in a Tertiary Center in Mexico.

    PubMed

    Santamaria, Eric; de la Concha, Erika

    2016-10-01

    Microsurgical reconstruction of complex midfacial and maxillectomy defects is among the most challenging procedures in plastic surgery, and it often requires composite flaps to improve functional and aesthetic results. Various factors have been identified as having influence in the outcome of microsurgical reconstruction. In this article, the authors present their experience with immediate and delayed reconstruction of complex maxillectomy defects in a tertiary center in Mexico. The authors present a total of 37 patients with microsurgical reconstruction of a complex maxillectomy defect; 13 patients had immediate and 24 had delayed reconstructions. The authors recommend doing immediate reconstruction when feasible. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. New mixed valence defect dicubane cobalt(II)/cobalt(III) complex: Synthesis, crystal structure, photoluminescence and magnetic properties

    NASA Astrophysics Data System (ADS)

    Coban, Mustafa Burak; Gungor, Elif; Kara, Hulya; Baisch, Ulrich; Acar, Yasemin

    2018-02-01

    A new defect dicubane cobalt(II)/cobalt(III), [(CoII2CoIII2L42(H2O)(CH3COO)(CH3COOH]. 4H2O complex (1) where H2L = [1-(3-hydroxypropyliminomethyl)naphthalene-2-ol], has been synthesized and characterized by element analysis, FT-IR, solid UV-Vis spectroscopy and single crystal X-ray diffraction. The crystal structure determination shows a cationic tetrameric arrangement consisting of a defect dicubane core with two missing vertexes. Each cobalt ion has a distorted octahedral geometry with six coordinate ordered CoII and CoIII ions. The solid state photoluminescence properties of complex (1) and its ligand H2L have been investigated under UV light at 349 nm in the visible region. H2L exhibits blue emission while complex (1) shows red emission at room temperature. Variable-temperature magnetic susceptibility measurements on the complex (1) in the range 2-300 K indicate an antiferromagnetic interaction.

  8. An inherited immunoglobulin class-switch recombination deficiency associated with a defect in the INO80 chromatin remodeling complex.

    PubMed

    Kracker, Sven; Di Virgilio, Michela; Schwartzentruber, Jeremy; Cuenin, Cyrille; Forveille, Monique; Deau, Marie-Céline; McBride, Kevin M; Majewski, Jacek; Gazumyan, Anna; Seneviratne, Suranjith; Grimbacher, Bodo; Kutukculer, Necil; Herceg, Zdenko; Cavazzana, Marina; Jabado, Nada; Nussenzweig, Michel C; Fischer, Alain; Durandy, Anne

    2015-04-01

    Immunoglobulin class-switch recombination defects (CSR-D) are rare primary immunodeficiencies characterized by impaired production of switched immunoglobulin isotypes and normal or elevated IgM levels. They are caused by impaired T:B cooperation or intrinsic B cell defects. However, many immunoglobulin CSR-Ds are still undefined at the molecular level. This study's objective was to delineate new causes of immunoglobulin CSR-Ds and thus gain further insights into the process of immunoglobulin class-switch recombination (CSR). Exome sequencing in 2 immunoglobulin CSR-D patients identified variations in the INO80 gene. Functional experiments were performed to assess the function of INO80 on immunoglobulin CSR. We identified recessive, nonsynonymous coding variations in the INO80 gene in 2 patients affected by defective immunoglobulin CSR. Expression of wild-type INO80 in patients' fibroblastic cells corrected their hypersensitivity to high doses of γ-irradiation. In murine CH12-F3 cells, the INO80 complex accumulates at Sα and Eμ regions of the IgH locus, and downregulation of INO80 as well as its partners Reptin and Pontin impaired CSR. In addition, Reptin and Pontin were shown to interact with activation-induced cytidine deaminase. Finally, an abnormal separation of sister chromatids was observed upon INO80 downregulation in CH12-F3 cells, pinpointing its role in cohesin activity. INO80 deficiency appears to be associated with defective immunoglobulin CSR. We propose that the INO80 complex modulates cohesin function that may be required during immunoglobulin switch region synapsis. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  9. An inherited immunoglobulin class-switch recombination deficiency associated with a defect in the INO80 chromatin remodeling complex

    PubMed Central

    Kracker, Sven; Di Virgilio, Michela; Schwartzentruber, Jeremy; Cuenin, Cyrille; Forveille, Monique; Deau, Marie-Céline; McBride, Kevin M.; Majewski, Jacek; Gazumyan, Anna; Seneviratne, Suranjith; Grimbacher, Bodo; Kutukculer, Necil; Herceg, Zdenko; Cavazzana, Marina; Jabado, Nada; Nussenzweig, Michel C.; Fischer, Alain; Durandy, Anne

    2015-01-01

    Background Immunoglobulin class-switch recombination defects (CSR-D) are rare primary immunodeficiencies characterized by impaired production of switched immunoglobulin isotypes and normal or elevated IgM levels. They are caused by impaired T:B cooperation or intrinsic B cell defects. However, many immunoglobulin CSR-Ds are still undefined at the molecular level. Objective This study's objective was to delineate new causes of immunoglobulin CSR-Ds and thus gain further insights into the process of immunoglobulin class-switch recombination (CSR). Methods Exome sequencing in 2 immunoglobulin CSR-D patients identified variations in the INO80 gene. Functional experiments were performed to assess the function of INO80 on immunoglobulin CSR. Results We identified recessive, nonsynonymous coding variations in the INO80 gene in 2 patients affected by defective immunoglobulin CSR. Expression of wild-type INO80 in patients' fibroblastic cells corrected their hypersensitivity to high doses of γ-irradiation. In murine CH12-F3 cells, the INO80 complex accumulates at Sα and Eμ regions of the IgH locus, and downregulation of INO80 as well as its partners Reptin and Pontin impaired CSR. In addition, Reptin and Pontin were shown to interact with activation-induced cytidine deaminase. Finally, an abnormal separation of sister chromatids was observed upon INO80 downregulation in CH12-F3 cells, pinpointing its role in cohesin activity. Conclusion INO80 deficiency appears to be associated with defective immunoglobulin CSR. We propose that the INO80 complex modulates cohesin function that may be required during immunoglobulin switch region synapsis. PMID:25312759

  10. Interaction Between a Steady Detonation Wave in Nitromethane and Geometrical Complex Confinement Defects

    NASA Astrophysics Data System (ADS)

    Crouzet, B.; Soulard, L.; Carion, N.; Manczur, P.

    2007-12-01

    Two copper cylinder expansion tests were carried out on nitromethane. They differ from the classical cylinder test in that the liner includes evenly-spaced protruding circular defects. The aim is to study how a detonation front propagating in the liquid explosive interacts with the confining material defects. The subsequent motion of the metal, accelerated by the expanding detonation products, is measured using a range of diagnostic techniques: electrical probes, a rapid framing camera, a glass block associated with a streak camera and velocity laser interferometers. The different experimental records have been examined in the light of previous classical cylinder test measurements, simple 2D theoretical shock polar analysis results and 2D numerical simulations.

  11. Interaction between a steady detonation wave in nitromethane and geometrical complex confinement defects.

    NASA Astrophysics Data System (ADS)

    Crouzet, Blandine; Carion, Noel; Manczur, Philippe

    2007-06-01

    It is well known that detonation propagation is altered if the explosive is encased in an inert confining material. But in practice, explosives are rarely used without confinement and particular attention must be paid to the problem of explosive/confinement interactions. In this work, we have carried out two copper cylinder expansion tests on nitromethane. They differ from the classical cylinder test in that the liner includes evenly-spaced protruding circular defects. The aim is to study how a detonation front propagating in the liquid explosive interacts with the confining material defects. The subsequent motion of the metal, accelerated by the expanding detonation products, is measured using a range of diagnostic techniques: electrical probes, rapid framing camera, glass block associated with streak camera and velocity laser interferometers. The different experimental records have been examined in the light of a simple 2D theoretical shock polar analysis and 2D numerical simulations.

  12. Osseocutaneous radial forearm free tissue transfer for repair of complex midfacial defects.

    PubMed

    Chepeha, Douglas B; Moyer, Jeffrey S; Bradford, Carol R; Prince, Mark E; Marentette, Lawrence; Teknos, Theodoros N

    2005-06-01

    To evaluate the resulting aesthetics, function, and donor site morbidity of the osseocutaneous radial forearm free flap (OCRFFF) used for midface reconstruction. Prospective case series and a retrospective review of results. Ten patients from an academic practice who underwent reconstruction at the University of Michigan Hospitals between 1995 and 2001. All patients had maxillectomy defects in which the entire infraorbital rim was reconstructed with an OCRFFF. Of the 10 patients included in the study, 3 underwent a total maxillectomy with orbital exenteration, 4 had a total maxillectomy without orbital exenteration, and 3 had a limited maxillectomy that did not involve the palate. Patients with palatal defects underwent reconstruction with a prosthetic palatal obturator. Facial contour and aesthetic results, speech understandability, ability to eat solid foods, oronasal separation, socializing outside the home, and return-to-work status. Flap success, donor site morbidity, and orbital complications were also studied. Mean +/- SEM follow-up was 23.2 +/- 5.0 months. A modified Funk facial deformity scale was used, and 7 of the 10 patients had either no deformity or minimal deformity. The mean aesthetic score for these reconstructions was 2.1 +/- 0.3 on a scale of 1 to 4, with 1 representing no deformity and 4 representing a severe deformity. All patients returned to a solid diet and had understandable speech, although patients who had an orbital exenteration trended to poorer scores. All patients socialized either frequently or occasionally outside the home, and all patients not retired or disabled prior to surgery returned to work. The OCRFFF reconstruction of the infraorbital rim in patients with total maxillectomy defects and obturator of the palatal defect controls orbital complications and optimizes aesthetic outcome while achieving nearly normal palatal function.

  13. Fetal Alcohol Spectrum Disorder (FASD) Associated Neural Defects: Complex Mechanisms and Potential Therapeutic Targets

    PubMed Central

    Muralidharan, Pooja; Sarmah, Swapnalee; Zhou, Feng C.; Marrs, James A.

    2013-01-01

    Fetal alcohol spectrum disorder (FASD), caused by prenatal alcohol exposure, can result in craniofacial dysmorphism, cognitive impairment, sensory and motor disabilities among other defects. FASD incidences are as high as 2% to 5 % children born in the US, and prevalence is higher in low socioeconomic populations. Despite various mechanisms being proposed to explain the etiology of FASD, the molecular targets of ethanol toxicity during development are unknown. Proposed mechanisms include cell death, cell signaling defects and gene expression changes. More recently, the involvement of several other molecular pathways was explored, including non-coding RNA, epigenetic changes and specific vitamin deficiencies. These various pathways may interact, producing a wide spectrum of consequences. Detailed understanding of these various pathways and their interactions will facilitate the therapeutic target identification, leading to new clinical intervention, which may reduce the incidence and severity of these highly prevalent preventable birth defects. This review discusses manifestations of alcohol exposure on the developing central nervous system, including the neural crest cells and sensory neural placodes, focusing on molecular neurodevelopmental pathways as possible therapeutic targets for prevention or protection. PMID:24961433

  14. Fetal Alcohol Spectrum Disorder (FASD) Associated Neural Defects: Complex Mechanisms and Potential Therapeutic Targets.

    PubMed

    Muralidharan, Pooja; Sarmah, Swapnalee; Zhou, Feng C; Marrs, James A

    2013-06-19

    Fetal alcohol spectrum disorder (FASD), caused by prenatal alcohol exposure, can result in craniofacial dysmorphism, cognitive impairment, sensory and motor disabilities among other defects. FASD incidences are as high as 2% to 5 % children born in the US, and prevalence is higher in low socioeconomic populations. Despite various mechanisms being proposed to explain the etiology of FASD, the molecular targets of ethanol toxicity during development are unknown. Proposed mechanisms include cell death, cell signaling defects and gene expression changes. More recently, the involvement of several other molecular pathways was explored, including non-coding RNA, epigenetic changes and specific vitamin deficiencies. These various pathways may interact, producing a wide spectrum of consequences. Detailed understanding of these various pathways and their interactions will facilitate the therapeutic target identification, leading to new clinical intervention, which may reduce the incidence and severity of these highly prevalent preventable birth defects. This review discusses manifestations of alcohol exposure on the developing central nervous system, including the neural crest cells and sensory neural placodes, focusing on molecular neurodevelopmental pathways as possible therapeutic targets for prevention or protection.

  15. Sonic Hedgehog mutations are not a common cause of congenital hypopituitarism in the absence of complex midline cerebral defects.

    PubMed

    Paulo, Sabrina Soares; Fernandes-Rosa, Fábio L; Turatti, Wendy; Coeli-Lacchini, Fernanda Borchers; Martinelli, Carlos E; Nakiri, Guilherme S; Moreira, Ayrton C; Santos, Antônio C; de Castro, Margaret; Antonini, Sonir R

    2015-04-01

    Sonic Hedgehog (SHH) and GLI2, an obligatory mediator of SHH signal transduction, are holoprosencephaly (HPE)-associated genes essential in pituitary formation. GLI2 variants have been found in patients with congenital hypopituitarism without complex midline cerebral defects (MCD). However, data on the occurrence of SHH mutations in these patients are limited. We screened for SHH and GLI2 mutations or copy number variations (CNV) in patients with congenital hypopituitarism without MCD or with variable degrees of MCD. Detailed data on clinical, laboratory and neuroimaging findings of 115 patients presenting with congenital hypopituitarism without MCD, septo-optic dysplasia or HPE were analysed. The SHH and GLI2 genes were directly sequenced, and the presence of gene CNV was analysed by multiplex ligation-dependent probe amplification (MLPA). Anterior pituitary deficiency was found in 74% and 53% of patients with SOD or HPE, respectively. Diabetes insipidus was common in patients with HPE (47%) but infrequent in patients with congenital hypopituitarism or SOD (7% and 8%, respectively). A single heterozygous nonsense SHH mutation (p.Tyr175Ter) was found in a patient presenting with hypopituitarism and alobar HPE. No other SHH mutations or CNV were found. Nine GLI2 variations (8 missense and 1 frameshift) including a homozygous and a compound heterozygous variation were found in patients with congenital hypopituitarism or SOD, but not in HPE patients. No GLI2 CNV were found. SHH mutations or copy number variations are not a common cause of congenital hypopituitarism in patients without complex midline cerebral defects. GLI2 variants are found in some patients with congenital hypopituitarism without complex midline cerebral defects or septo-optic dysplasia. However, functional analyses of these variants are needed to strengthen genotype-phenotype relationship. © 2014 John Wiley & Sons Ltd.

  16. A lightning strike to the head causing a visual cortex defect with simple and complex visual hallucinations

    PubMed Central

    Kleiter, Ingo; Luerding, Ralf; Diendorfer, Gerhard; Rek, Helga; Bogdahn, Ulrich; Schalke, Berthold

    2007-01-01

    The case of a 23‐year‐old mountaineer who was hit by a lightning strike to the occiput causing a large central visual field defect and bilateral tympanic membrane ruptures is described. Owing to extreme agitation, the patient was set to a drug‐induced coma for 3 days. After extubation, she experienced simple and complex visual hallucinations for several days, but otherwise recovered largely. Neuropsychological tests revealed deficits in fast visual detection tasks and non‐verbal learning, and indicated a right temporal lobe dysfunction, consistent with a right temporal focus on electroencephalography. Four months after the accident, she developed a psychological reaction consisting of nightmares with reappearance of the complex visual hallucinations and a depressive syndrome. Using the European Cooperation for Lightning Detection network, a meteorological system for lightning surveillance, the exact geographical location and nature of the lightning flash were retrospectively retraced. PMID:17369595

  17. A lightning strike to the head causing a visual cortex defect with simple and complex visual hallucinations

    PubMed Central

    Kleiter, Ingo; Luerding, Ralf; Diendorfer, Gerhard; Rek, Helga; Bogdahn, Ulrich; Schalke, Berthold

    2009-01-01

    The case of a 23-year-old mountaineer who was hit by a lightning strike to the occiput causing a large central visual field defect and bilateral tympanic membrane ruptures is described. Owing to extreme agitation, the patient was sent into a drug-induced coma for 3 days. After extubation, she experienced simple and complex visual hallucinations for several days, but otherwise largely recovered. Neuropsychological tests revealed deficits in fast visual detection tasks and non-verbal learning and indicated a right temporal lobe dysfunction, consistent with a right temporal focus on electroencephalography. At 4 months after the accident, she developed a psychological reaction consisting of nightmares, with reappearance of the complex visual hallucinations and a depressive syndrome. Using the European Cooperation for Lightning Detection network, a meteorological system for lightning surveillance, the exact geographical location and nature of the lightning strike were retrospectively retraced PMID:21734915

  18. One-stage reconstruction of the complex midfoot defect with a multiple osteotomized free fibular osteocutaneous flap: case report and literature review.

    PubMed

    Lykoudis, Efstathios G; Dimitrios, Pafilas; Alexandros, Beris E

    2010-01-01

    Complex midfoot defects represent a reconstructive challenge since midfoot plays a key role in standing and gait. We report the case of a 27-year-old patient with a complex midfoot defect due to a high-energy gun shot injury. The defect included the tarsometatarsal complex, all three arches of the foot, and the overlying dorsal skin of the foot. Reconstruction was achieved in a single stage with a free fibular osteocutaneous flap. The fibula was osteotomized into three segments, which were used to reconstruct the bone defects, while the skin paddle of the flap was used for stable soft tissue coverage of the reconstructed bony skeleton. Early and late postoperative periods were uneventful. Bone incorporation was radiographically evident at 12 weeks, and full weight bearing was possible at 6 months postop. Final follow up, at 2 years postop, showed a very good functional and esthetic outcome.

  19. [Defects in TOR regulatory complexes retard aging and carbonyl/oxidative stress development in yeast Saccharomyces cerevisiae].

    PubMed

    Homza, B V; Vasyl'kovs'ka, R A; Semchyshyn, H M

    2014-01-01

    TOR signaling pathway first described in yeast S. cerevisiae is the highly conserved regulator of eukaryotic cell growth, aging and stress resistance. The effect of nitrogen sources, in particular amino acids, on the activity of TOR signaling pathway is well studied, however its relation to carbohydrates is poor understood. The aim of the present study is expanding of our understanding of potential role of TOR regulatory complexes in development of carbonyl/oxidative stress that can result from yeast cultivation on glucose and fructose. It has been shown that the level of alpha-dicarbonyl compounds and protein carbonyl groups increased with time of yeast cultivation and was higher in cells grown on fructose that demonstrated their accelerated aging and carbonyl/oxidative stress development as compared with cells grown on glucose. The strains defective in TOR proteins cultivated in the presence of glucose as well as fructose demonstrated lower markers of the stress and aging than parental strain. Thus these data confirmed the previous conclusion on fructose more potent ability to cause carbonyl/oxidative stress and accelerated aging in S. cerevisiae as compared with glucose. However, defects in TOR regulatory complexes retard aging and development of the stress in yeast independent on the type of carbohydrate in the cultivation medium.

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

    PubMed

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

    2017-12-25

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

  1. Negative Pressure Wound Therapy (NPWT) to Treat Complex Defect of the Leg after Electrical Burn.

    PubMed

    Tevanov, Iulia; Enescu, Dan M; Bălănescu, Radu; Sterian, G; Ulici, Alexandru

    2016-01-01

    Negative pressure wound therapy is a non-invasive treatment that uses under atmospheric pressure to increase blood supply to the wound, stimulating the formation of granulation tissue, angiogenesis, proliferation of fibroblasts and endothelial cells. Negative pressure therapy has also the ability to decrease the bacterial load, reduce swelling and decrease exudate while maintaining a moist environment that facilitates healing. Our patient, a 17 year old male, suffered major third and fourth-degree high voltage electrical burns on 60% of the body surface, in November 2011. After the excision of the necrotic tissue (muscles and tendons), the lower extremity of the right leg- the tibial bone, the fibula, external and internal malleoli became exposed circularly. The soft-tissue defect was partially covered by using an internal twin muscle flap and free split skin. Then, a cross leg flap technique has been used, partially covering the defect with a contralateral thigh flap. Surface swab cultures were positive for Pseudomonas aeruginosa. In October 2013 the patient was transferred to our department. The clinical examination of the right leg showed that the tibial bone had been exposed on an area of 15/3 cm in the lower half. The peroneal malleolus had also been exposed. The resection of the devitalized, exposed tibia and the avivement of the wound edges were performed. Then the NPWT was started and performed by intermittent suction. Local cleansing, soft-tissue avivement and dressing changes were performed twice a week for 6 weeks. After six weeks of NPWT and eleven dressing changes under general anaesthesia, the wounds were ready for skin grafting. Granulation tissue was formed, covering the entire surface of both the tibia bone and the peroneal malleolus. Both receptor beds were covered with free skin graft harvested from the ipsilateral thigh. The mechanical suture of the skin grafts was performed and the grafts were covered with damp dressing. By using the NPWT it

  2. Phospho-ubiquitin-PARK2 complex as a marker for mitophagy defects.

    PubMed

    Callegari, Sylvie; Oeljeklaus, Silke; Warscheid, Bettina; Dennerlein, Sven; Thumm, Michael; Rehling, Peter; Dudek, Jan

    2017-01-02

    The E3 ubiquitin ligase PARK2 and the mitochondrial protein kinase PINK1 are required for the initiation of mitochondrial damage-induced mitophagy. Together, PARK2 and PINK1 generate a phospho-ubiquitin signal on outer mitochondrial membrane proteins that triggers recruitment of the autophagy machinery. This paper describes the detection of a defined 500-kDa phospho-ubiquitin-rich PARK2 complex that accumulates on mitochondria upon treatment with the membrane uncoupler CCCP. Formation of this complex is dependent on the presence of PINK1 and is absent in mutant forms of PARK2, whereby mitophagy is also arrested. These results signify a functional signaling complex that is essential for the progression of mitophagy. The visualization of the PARK2 signaling complex represents a novel marker for this critical step in mitophagy and can be used to monitor mitophagy progression in PARK2 mutants and to uncover additional upstream factors required for PARK2-mediated mitophagy signaling.

  3. Syndrome complex of bone marrow failure and pulmonary fibrosis predicts germline defects in telomerase

    PubMed Central

    Parry, Erin M.; Alder, Jonathan K.; Qi, Xiaodong; Chen, Julian J.-L.

    2011-01-01

    Mutations in the essential telomerase components hTERT and hTR cause dyskeratosis congenita, a bone marrow failure syndrome characterized by mucocutaneous features. Some (∼ 3%) sporadic aplastic anemia (AA) and idiopathic pulmonary fibrosis cases also carry mutations in hTERT and hTR. Even though it can affect clinical outcome, because the mutation frequency is rare, genetic testing is not standard. We examined whether the cooccurrence of bone marrow failure and pulmonary fibrosis in the same individual or family enriches for the presence of a telomerase mutation. Ten consecutive individuals with a total of 36 family members who fulfilled these criteria carried a germline mutant telomerase gene (100%). The mean age of onset for individuals with AA was significantly younger than that for those with pulmonary fibrosis (14 vs 51; P < .0001). Families displayed autosomal dominant inheritance and there was an evolving pattern of genetic anticipation, with the older generation primarily affected by pulmonary fibrosis and successive generations by bone marrow failure. The cooccurrence of AA and pulmonary fibrosis in a single patient or family is highly predictive for the presence of a germline telomerase defect. This diagnosis affects the choice of bone marrow transplantation preparative regimen and can prevent morbidity. PMID:21436073

  4. Phenotypic Spectrum in Osteogenesis Imperfecta Due to Mutations in TMEM38B: Unraveling a Complex Cellular Defect.

    PubMed

    Webb, Emma A; Balasubramanian, Meena; Fratzl-Zelman, Nadja; Cabral, Wayne A; Titheradge, Hannah; Alsaedi, Atif; Saraff, Vrinda; Vogt, Julie; Cole, Trevor; Stewart, Susan; Crabtree, Nicola J; Sargent, Brandi M; Gamsjaeger, Sonja; Paschalis, Eleftherios P; Roschger, Paul; Klaushofer, Klaus; Shaw, Nick J; Marini, Joan C; Högler, Wolfgang

    2017-06-01

    Recessive mutations in TMEM38B cause type XIV osteogenesis imperfecta (OI) by dysregulating intracellular calcium flux. Clinical and bone material phenotype description and osteoblast differentiation studies. Natural history study in pediatric research centers. Eight patients with type XIV OI. Clinical examinations included bone mineral density, radiographs, echocardiography, and muscle biopsy. Bone biopsy samples (n = 3) were analyzed using histomorphometry, quantitative backscattered electron microscopy, and Raman microspectroscopy. Cellular differentiation studies were performed on proband and control osteoblasts and normal murine osteoclasts. Type XIV OI clinical phenotype ranges from asymptomatic to severe. Previously unreported features include vertebral fractures, periosteal cloaking, coxa vara, and extraskeletal features (muscular hypotonia, cardiac abnormalities). Proband lumbar spine bone density z score was reduced [median -3.3 (range -4.77 to +0.1; n = 7)] and increased by +1.7 (1.17 to 3.0; n = 3) following bisphosphonate therapy. TMEM38B mutant bone has reduced trabecular bone volume, osteoblast, and particularly osteoclast numbers, with >80% reduction in bone resorption. Bone matrix mineralization is normal and nanoporosity low. We demonstrate a complex osteoblast differentiation defect with decreased expression of early markers and increased expression of late and mineralization-related markers. Predominance of trimeric intracellular cation channel type B over type A expression in murine osteoclasts supports an intrinsic osteoclast defect underlying low bone turnover. OI type XIV has a bone histology, matrix mineralization, and osteoblast differentiation pattern that is distinct from OI with collagen defects. Probands are responsive to bisphosphonates and some show muscular and cardiovascular features possibly related to intracellular calcium flux abnormalities. Copyright © 2017 Endocrine Society

  5. Defect engineering of complex semiconductor alloys: Cu2-2xMxO1-yXy

    NASA Astrophysics Data System (ADS)

    Lany, Stephan; Stevanovic, Vladan

    2013-03-01

    The electrical properties of semiconductors are generally controlled via doping, i.e., the incorporation of dilute concentrations of aliovalent impurity atoms, whereas the band structure properties (gap, effective masses, optical properties) are manipulated by alloying, i.e., the incorporation of much larger amounts of isovalent elements. Theoretical approaches usually address either doping or alloying, but rarely both problems at the same time. By combining defect supercell calculations, GW quasi-particle energy calculation, and thermodynamic modeling, we study the range of electrical and band structure properties accessible by alloying aliovalent cations (M = Mg, Zn, Cd) and isovalent anions (X = S, Se) in Cu2O. In order to extend dilute defect models to higher concentrations, we take into account the association/dissociation of defect pairs and complexes, as well as the composition dependence of the band gap and the band edge energies. Considering a composition window for the Cu2-2xMxO1-yXy alloys of 0 <= (x,y) <= 0.2, we predict a wide range of possible band gaps from 1.7 to 2.6 eV, and net doping concentrations between p = 1019 cm-3 and n = 1017cm-3, notably achieving type conversion from p- to n-type at Zn or Cd compositions around x = 0.1. This work is supported as part of the SunShot initiative by the U. S. Department of Energy, Office of Energy Efficiency and Renewable Energy under Contract No. DE-AC36-08GO28308 to NREL.

  6. The Pch2 AAA+ ATPase promotes phosphorylation of the Hop1 meiotic checkpoint adaptor in response to synaptonemal complex defects

    PubMed Central

    Herruzo, Esther; Ontoso, David; González-Arranz, Sara; Cavero, Santiago; Lechuga, Ana; San-Segundo, Pedro A.

    2016-01-01

    Meiotic cells possess surveillance mechanisms that monitor critical events such as recombination and chromosome synapsis. Meiotic defects resulting from the absence of the synaptonemal complex component Zip1 activate a meiosis-specific checkpoint network resulting in delayed or arrested meiotic progression. Pch2 is an evolutionarily conserved AAA+ ATPase required for the checkpoint-induced meiotic block in the zip1 mutant, where Pch2 is only detectable at the ribosomal DNA array (nucleolus). We describe here that high levels of the Hop1 protein, a checkpoint adaptor that localizes to chromosome axes, suppress the checkpoint defect of a zip1 pch2 mutant restoring Mek1 activity and meiotic cell cycle delay. We demonstrate that the critical role of Pch2 in this synapsis checkpoint is to sustain Mec1-dependent phosphorylation of Hop1 at threonine 318. We also show that the ATPase activity of Pch2 is essential for its checkpoint function and that ATP binding to Pch2 is required for its localization. Previous work has shown that Pch2 negatively regulates Hop1 chromosome abundance during unchallenged meiosis. Based on our results, we propose that, under checkpoint-inducing conditions, Pch2 also possesses a positive action on Hop1 promoting its phosphorylation and its proper distribution on unsynapsed chromosome axes. PMID:27257060

  7. The Pch2 AAA+ ATPase promotes phosphorylation of the Hop1 meiotic checkpoint adaptor in response to synaptonemal complex defects.

    PubMed

    Herruzo, Esther; Ontoso, David; González-Arranz, Sara; Cavero, Santiago; Lechuga, Ana; San-Segundo, Pedro A

    2016-09-19

    Meiotic cells possess surveillance mechanisms that monitor critical events such as recombination and chromosome synapsis. Meiotic defects resulting from the absence of the synaptonemal complex component Zip1 activate a meiosis-specific checkpoint network resulting in delayed or arrested meiotic progression. Pch2 is an evolutionarily conserved AAA+ ATPase required for the checkpoint-induced meiotic block in the zip1 mutant, where Pch2 is only detectable at the ribosomal DNA array (nucleolus). We describe here that high levels of the Hop1 protein, a checkpoint adaptor that localizes to chromosome axes, suppress the checkpoint defect of a zip1 pch2 mutant restoring Mek1 activity and meiotic cell cycle delay. We demonstrate that the critical role of Pch2 in this synapsis checkpoint is to sustain Mec1-dependent phosphorylation of Hop1 at threonine 318. We also show that the ATPase activity of Pch2 is essential for its checkpoint function and that ATP binding to Pch2 is required for its localization. Previous work has shown that Pch2 negatively regulates Hop1 chromosome abundance during unchallenged meiosis. Based on our results, we propose that, under checkpoint-inducing conditions, Pch2 also possesses a positive action on Hop1 promoting its phosphorylation and its proper distribution on unsynapsed chromosome axes. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  8. Management of complex abdominal wall defects associated with penetrating abdominal trauma.

    PubMed

    Arul, G Suren; Sonka, B J; Lundy, J B; Rickard, R F; Jeffery, S L A

    2015-03-01

    The paradigm of Damage Control Surgery (DCS) has radically improved the management of abdominal trauma, but less well described are the options for managing the abdominal wall itself in an austere environment. This article describes a series of patients with complex abdominal wall problems managed at the UK-led Role 3 Medical Treatment Facility (MTF) in Camp Bastion, Afghanistan. Contemporaneous review of a series of patients with complex abdominal wall injuries who presented to the Role 3 MTF between July and November 2012. Five patients with penetrating abdominal trauma associated with significant damage to the abdominal wall were included. All patients were managed using DCS principles, leaving the abdominal wall open at the end of the first procedure. Subsequent management of the abdominal wall was determined by a multidisciplinary team of general and plastic surgeons, intensivists and specialist nurses. The principles of management identified included minimising tissue loss on initial laparotomy by joining adjacent wounds and marginal debridement of dead tissue; contraction of the abdominal wall was minimised by using topical negative pressure dressing and dermal-holding sutures. Definitive closure was timed to allow oedema to settle and sepsis to be controlled. Closure techniques include delayed primary closure with traction sutures, components separation, and mesh closure with skin grafting. A daily multidisciplinary team discussion was invaluable for optimal decision making regarding the most appropriate means of abdominal closure. Dermal-holding sutures were particularly useful in preventing myostatic contraction of the abdominal wall. A simple flow chart was developed to aid decision making in these patients. This flow chart may prove especially useful in a resource-limited environment in which returning months or years later for closure of a large ventral hernia may not be possible. Published by the BMJ Publishing Group Limited. For permission to use

  9. Defective complex I assembly due to C20orf7 mutations as a new cause of Leigh syndrome

    PubMed Central

    Gerards, M; Sluiter, W; van den Bosch, B J C; de Wit, L E A; Calis, C M H; Frentzen, M; Akbari, H; Schoonderwoerd, K; Scholte, H R; Jongbloed, R J; Hendrickx, A T M; de Coo, I F M

    2009-01-01

    Background Leigh syndrome is an early onset, progressive, neurodegenerative disorder with developmental and motor skills regression. Characteristic magnetic resonance imaging abnormalities consist of focal bilateral lesions in the basal ganglia and/or the brainstem. The main cause is a deficiency in oxidative phosphorylation due to mutations in an mtDNA or nuclear oxidative phosphorylation gene. Methods and results A consanguineous Moroccan family with Leigh syndrome comprise 11 children, three of which are affected. Marker analysis revealed a homozygous region of 11.5 Mb on chromosome 20, containing 111 genes. Eight possible mitochondrial candidate genes were sequenced. Patients were homozygous for an unclassified variant (p.P193L) in the cardiolipin synthase gene (CRLS1). As this variant was present in 20% of a Moroccan control population and enzyme activity was only reduced to 50%, this could not explain the rare clinical phenotype in our family. Patients were also homozygous for an amino acid substitution (p.L159F) in C20orf7, a new complex I assembly factor. Parents were heterozygous and unaffected sibs heterozygous or homozygous wild type. The mutation affects the predicted S-adenosylmethionine (SAM) dependent methyltransferase domain of C20orf7, possibly involved in methylation of NDUFB3 during the assembly process. Blue native gel electrophoresis showed an altered complex I assembly with only 30–40% of mature complex I present in patients and 70–90% in carriers. Conclusions A new cause of Leigh syndrome can be a defect in early complex I assembly due to C20orf7 mutations. PMID:19542079

  10. Robotic Transversus Abdominis Release (TAR): is it possible to offer minimally invasive surgery for abdominal wall complex defects?

    PubMed

    Amaral, Maria Vitória França DO; Guimarães, José Ricardo; Volpe, Paula; Oliveira, Flávio Malcher Martins DE; Domene, Carlos Eduardo; Roll, Sérgio; Cavazzola, Leandro Totti

    2017-01-01

    We describe the preliminary national experience and the early results of the use of robotic surgery to perform the posterior separation of abdominal wall components by the Transversus Abdominis Release (TAR) technique for the correction of complex defects of the abdominal wall. We performed the procedures between 04/2/2015 and 06/15/2015 and the follow-up time was up to six months, with a minimum of two months. The mean surgical time was five hours and 40 minutes. Two patients required laparoscopic re-intervention, since one developed hernia by peritoneal migration of the mesh and one had mesh extrusion. The procedure proved to be technically feasible, with a still long surgical time. Considering the potential advantages of robotic surgery and those related to TAR and the results obtained when these two techniques are associated, we conclude that they seem to be a good option for the correction of complex abdominal wall defects. RESUMO Descrevemos a experiência preliminar nacional na utilização da cirurgia robótica para realizar a separação posterior de componentes da parede abdominal pela técnica transversus abdominis release (TAR) na correção de defeitos complexos da parede abdominal e seus resultados precoces. As cirurgias foram realizadas entre 02/04/2015 e 15/06/2015 e o tempo de acompanhamento dos resultados foi de até seis meses, com tempo mínimo de dois meses. O tempo cirúrgico médio foi de cinco horas e 40 minutos. Dois pacientes necessitaram reintervenção por laparoscopia, pois um desenvolveu hérnia por migração peritoneal da tela e um teve escape da tela. A cirurgia provou ser factível do ponto de vista técnico, com um tempo cirúrgico ainda elevado. Tendo em vista as vantagens potenciais da cirurgia robótica e aquelas relacionadas ao TAR e os resultados obtidos ao se associar essas duas técnicas, conclui-se que elas parecem ser uma boa opção para a correção de defeitos complexos da parede abdominal.

  11. A catalytic defect in mitochondrial respiratory chain complex I due to a mutation in NDUFS2 in a patient with Leigh syndrome.

    PubMed

    Ngu, Lock Hock; Nijtmans, Leo G; Distelmaier, Felix; Venselaar, Hanka; van Emst-de Vries, Sjenet E; van den Brand, Mariël A M; Stoltenborg, Berendien J M; Wintjes, Liesbeth T; Willems, Peter H; van den Heuvel, Lambertus P; Smeitink, Jan A; Rodenburg, Richard J T

    2012-02-01

    In this study, we investigated the pathogenicity of a homozygous Asp446Asn mutation in the NDUFS2 gene of a patient with a mitochondrial respiratory chain complex I deficiency. The clinical, biochemical, and genetic features of the NDUFS2 patient were compared with those of 4 patients with previously identified NDUFS2 mutations. All 5 patients presented with Leigh syndrome. In addition, 3 out of 5 showed hypertrophic cardiomyopathy. Complex I amounts in the patient carrying the Asp446Asn mutation were normal, while the complex I activity was strongly reduced, showing that the NDUFS2 mutation affects complex I enzymatic function. By contrast, the 4 other NDUFS2 patients showed both a reduced amount and activity of complex I. The enzymatic defect in fibroblasts of the patient carrying the Asp446Asn mutation was rescued by transduction of wild type NDUFS2. A 3-D model of the catalytic core of complex I showed that the mutated amino acid residue resides near the coenzyme Q binding pocket. However, the K(M) of complex I for coenzyme Q analogs of the Asp446Asn mutated complex I was similar to the K(M) observed in other complex I defects and in controls. We propose that the mutation interferes with the reduction of coenzyme Q or with the coupling of coenzyme Q reduction with the conformational changes involved in proton pumping of complex I. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Defective pairing and synaptonemal complex formation in a Sordaria mutant (spo44) with a translocated segment of the nucleolar organizer.

    PubMed

    Zickler, D; de Lares, L; Moreau, P J; Leblon, G

    1985-01-01

    The recessive meiotic mutant spo44 of Sordaria macrospora, with 90% ascospore abortion, exhibits striking effects on recombination (67% decrease), irregular segregation of the almost unpaired homologues, and a decrease in chiasma frequency in the few cases where bivalents are formed. Three-dimensional reconstructions of ten prophase nuclei indicate that pairing, as judged by the absence of fully formed synaptonemal complexes (SC), is not achieved although lateral elements (LE) assemble. The pairing failure is attributable to defects in the alignment of homologous chromosomes. The leptotene alignment seen in the wild type before SC formation was not observed in the spo44 nuclei. Dense material, considered to be precursor of SC central elements, was found scattered among the LE in two nuclei. The behaviour of spo44 substantiates the hypothesis that chromosome matching and SC formation are separable events. - The total length of the LE in the mutant is the same as in the wild type, but due to variable numbers and length of the individual LE, homologues cannot be lined up. Light microscopic observations indicate that the irregular length and number of LE is due to extensive chromosome breakage. The wild-type function corresponding to spo44 is required for both LE integrity and chromosome matching. Reconstructions of heterozygous nuclei reveal the presence of a supernumerary nucleolar organizer in one arm of chromosome 7. It is suggested that rDNA has been inserted into a gene whose function is involved in pairing or into a controlling sequence that interacts with the pairing process.

  13. Identification of vacancy defect complexes in transparent semiconducting oxides ZnO, In2O3 and SnO2.

    PubMed

    Makkonen, Ilja; Korhonen, Esa; Prozheeva, Vera; Tuomisto, Filip

    2016-06-08

    Positron annihilation spectroscopy, when combined with supporting high-quality modeling of positron states and annihilation in matter, is a powerful tool for detailed defect identification of vacancy-type defects in semiconductors and oxides. Here we demonstrate that the Doppler broadening of the positron annihilation radiation is a very sensitive means for observing the oxygen environment around cation vacancies, the main open-volume defects trapping positrons in measurements made for transparent semiconducting oxides. Changes in the positron annihilation signal due to external manipulation such as irradiation and annealing can be correlated with the associated changes in the sizes of the detected vacancy clusters. Our examples for ZnO, In2O3 and SnO2 demonstrate that oxygen vacancies in oxides can be detected directly using positron annihilation spectroscopy when they are complexed with cation vacancies.

  14. Identification of vacancy defect complexes in transparent semiconducting oxides ZnO, In2O3 and SnO2

    NASA Astrophysics Data System (ADS)

    Makkonen, Ilja; Korhonen, Esa; Prozheeva, Vera; Tuomisto, Filip

    2016-06-01

    Positron annihilation spectroscopy, when combined with supporting high-quality modeling of positron states and annihilation in matter, is a powerful tool for detailed defect identification of vacancy-type defects in semiconductors and oxides. Here we demonstrate that the Doppler broadening of the positron annihilation radiation is a very sensitive means for observing the oxygen environment around cation vacancies, the main open-volume defects trapping positrons in measurements made for transparent semiconducting oxides. Changes in the positron annihilation signal due to external manipulation such as irradiation and annealing can be correlated with the associated changes in the sizes of the detected vacancy clusters. Our examples for ZnO, In2O3 and SnO2 demonstrate that oxygen vacancies in oxides can be detected directly using positron annihilation spectroscopy when they are complexed with cation vacancies.

  15. Complex Interaction Mechanisms between Dislocations and Point Defects Studied in Pure Aluminium by a Two-Wave Acoustic Coupling Technique

    NASA Astrophysics Data System (ADS)

    Bremnes, O.; Progin, O.; Gremaud, G.; Benoit, W.

    1997-04-01

    Ultrasonic experiments using a two-wave coupling technique were performed on 99.999% pure Al in order to study the interaction mechanisms occurring between dislocations and point defects. The coupling technique consists in measuring the attenuation of ultrasonic waves during low-frequency stress cycles (t). One obtains closed curves () called signatures whose shape and evolution are characteristic of the interaction mechanism controlling the low-frequency dislocation motion. The signatures observed were attributed to the interaction of the dislocations with extrinsic point defects. A new interpretation of the evolution of the signatures measured below 200 K with respect to temperature and stress frequency had to be established: they are linked to depinning of immobile point defects, whereas a thermally activated depinning mechanism does not fit the observations. The signatures measured between 200 and 370 K were interpreted as dragging and depinning of extrinsic point defects which are increasingly mobile with temperature.

  16. Birth Defects

    MedlinePlus

    ... both. Some birth defects like cleft lip or neural tube defects are structural problems that can be ... during pregnancy is a key factor in causing neural tube defects. For most birth defects, the cause ...

  17. Utility and Scope of Rapid Prototyping in Patients with Complex Muscular Ventricular Septal Defects or Double-Outlet Right Ventricle: Does it Alter Management Decisions?

    PubMed

    Bhatla, Puneet; Tretter, Justin T; Ludomirsky, Achi; Argilla, Michael; Latson, Larry A; Chakravarti, Sujata; Barker, Piers C; Yoo, Shi-Joon; McElhinney, Doff B; Wake, Nicole; Mosca, Ralph S

    2017-01-01

    Rapid prototyping facilitates comprehension of complex cardiac anatomy. However, determining when this additional information proves instrumental in patient management remains a challenge. We describe our experience with patient-specific anatomic models created using rapid prototyping from various imaging modalities, suggesting their utility in surgical and interventional planning in congenital heart disease (CHD). Virtual and physical 3-dimensional (3D) models were generated from CT or MRI data, using commercially available software for patients with complex muscular ventricular septal defects (CMVSD) and double-outlet right ventricle (DORV). Six patients with complex anatomy and uncertainty of the optimal management strategy were included in this study. The models were subsequently used to guide management decisions, and the outcomes reviewed. 3D models clearly demonstrated the complex intra-cardiac anatomy in all six patients and were utilized to guide management decisions. In the three patients with CMVSD, one underwent successful endovascular device closure following a prior failed attempt at transcatheter closure, and the other two underwent successful primary surgical closure with the aid of 3D models. In all three cases of DORV, the models provided better anatomic delineation and additional information that altered or confirmed the surgical plan. Patient-specific 3D heart models show promise in accurately defining intra-cardiac anatomy in CHD, specifically CMVSD and DORV. We believe these models improve understanding of the complex anatomical spatial relationships in these defects and provide additional insight for pre/intra-interventional management and surgical planning.

  18. Synthetic Defects for Vibrothermography

    NASA Astrophysics Data System (ADS)

    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.

  19. A Study of BMP-2-Loaded Bipotential Electrolytic Complex around a Biphasic Calcium Phosphate-Derived (BCP) Scaffold for Repair of Large Segmental Bone Defect

    PubMed Central

    Paul, Kallyanashis; Padalhin, Andrew R.; Linh, Nguyen Thuy Ba; Kim, Boram; Sarkar, Swapan Kumar; Lee, Byong Taek

    2016-01-01

    A bipotential polyelectrolyte complex with biphasic calcium phosphate (BCP) powder dispersion provides an excellent option for protein adsorption and cell attachment and can facilitate enhanced bone regeneration. Application of the bipotential polyelectrolyte complex embedded in a spongy scaffold for faster healing of large segmental bone defects (LSBD) can be a promising endeavor in tissue engineering application. In the present study, a hollow scaffold suitable for segmental long bone replacement was fabricated by the sponge replica method applying the microwave sintering process. The fabricated scaffold was coated with calcium alginate at the shell surface, and genipin-crosslinked chitosan with biphasic calcium phosphate (BCP) dispersion was loaded at the central hollow core. The chitosan core was subsequently loaded with BMP-2. The electrolytic complex was characterized using SEM, porosity measurement, FTIR spectroscopy and BMP-2 release for 30 days. In vitro studies such as MTT, live/dead, cell proliferation and cell differentiation were performed. The scaffold was implanted into a 12 mm critical size defect of a rabbit radius. The efficacy of this complex is evaluated through an in vivo study, one and two month post implantation. BV/TV ratio for BMP-2 loaded sample was (42±1.76) higher compared with hollow BCP scaffold (32±0.225). PMID:27711142

  20. Succinate dehydrogenase (SDHx) mutations in pituitary tumors: could this be a new role for mitochondrial complex II and/or Krebs cycle defects?

    PubMed

    Xekouki, Paraskevi; Stratakis, Constantine A

    2012-12-01

    Succinate dehydrogenase (SDH) or mitochondrial complex II is a multimeric enzyme that is bound to the inner membrane of mitochondria and has a dual role as it serves both as a critical step of the tricarboxylic acid or Krebs cycle and as a member of the respiratory chain that transfers electrons directly to the ubiquinone pool. Mutations in SDH subunits have been implicated in the formation of familial paragangliomas (PGLs) and/or pheochromocytomas (PHEOs) and in Carney-Stratakis syndrome. More recently, SDH defects were associated with predisposition to a Cowden disease phenotype, renal, and thyroid cancer. We recently described a kindred with the coexistence of familial PGLs and an aggressive GH-secreting pituitary adenoma, harboring an SDHD mutation. The pituitary tumor showed loss of heterozygosity at the SDHD locus, indicating the possibility that SDHD's loss was causatively linked to the development of the neoplasm. In total, 29 cases of pituitary adenomas presenting in association with PHEOs and/or extra-adrenal PGLs have been reported in the literature since 1952. Although a number of other genetic defects are possible in these cases, we speculate that the association of PHEOs and/or PGLs with pituitary tumors is a new syndromic association and a novel phenotype for SDH defects.

  1. Drosophila variable nurse cells encodes Arrest defective 1 (ARD1), the catalytic subunit of the major N-terminal acetyltransferase complex

    PubMed Central

    Wang, Ying; Mijares, Michelle; Gall, Megan D.; Turan, Tolga; Javier, Anna; Bornemann, Douglas J; Manage, Kevin; Warrior, Rahul

    2010-01-01

    Mutations in the Drosophila variable nurse cells (vnc) gene result in female sterility and oogenesis defects, including egg chambers with too many or too few nurse cells. We show that vnc corresponds to Arrest Defective1 (Ard1) and encodes the catalytic subunit of NatA, the major N-terminal acetyl-transferase complex. While N-terminal acetylation is one of the most prevalent covalent protein modifications in eukaryotes, analysis of its role in development has been challenging since mutants that compromise NatA activity have not been described in any multicellular animal. Our data show that reduced ARD1 levels result in pleiotropic oogenesis defects including abnormal cyst encapsulation, desynchronized cystocyte division, disrupted nurse cell chromosome dispersion and abnormal chorion patterning, consistent with the wide range of predicted NatA substrates. Further we find that loss of Ard1 affects cell survival/proliferation and is lethal for the animal, providing the first demonstration that this modification is essential in higher eukaryotes. PMID:20882681

  2. Succinate dehydrogenase (SDHx) mutations in pituitary tumors: could this be a new role for mitochondrial complex II and/or Krebs cycle defects?

    PubMed Central

    Xekouki, Paraskevi; Stratakis, Constantine A

    2013-01-01

    Succinate dehydrogenase (SDH) or mitochondrial complex II is a multimeric enzyme that is bound to the inner membrane of mitochondria and has a dual role as it serves both as a critical step of the tricarboxylic acid or Krebs cycle and as a member of the respiratory chain that transfers electrons directly to the ubiquinone pool. Mutations in SDH subunits have been implicated in the formation of familial paragangliomas (PGLs) and/or pheochromocytomas (PHEOs) and in Carney–Stratakis syndrome. More recently, SDH defects were associated with predisposition to a Cowden disease phenotype, renal, and thyroid cancer. We recently described a kindred with the coexistence of familial PGLs and an aggressive GH-secreting pituitary adenoma, harboring an SDHD mutation. The pituitary tumor showed loss of heterozygosity at the SDHD locus, indicating the possibility that SDHD’s loss was causatively linked to the development of the neoplasm. In total, 29 cases of pituitary adenomas presenting in association with PHEOs and/or extra-adrenal PGLs have been reported in the literature since 1952. Although a number of other genetic defects are possible in these cases, we speculate that the association of PHEOs and/or PGLs with pituitary tumors is a new syndromic association and a novel phenotype for SDH defects. PMID:22889736

  3. CYTOLOGICAL CHARACTERIZATION OF PREMEIOTIC VERSUS POSTMEIOTIC DEFECTS PRODUCING HYBRID MALE STERILITY AMONG SIBLING SPECIES OF THE DROSOPHILA MELANOGASTER COMPLEX.

    PubMed

    Kulathinal, Rob; Singh, Rama S

    1998-08-01

    In accordance with Haldane's rule, hybridizations between species of the Drosophila simulans clade produce fertile females but sterile males. In this study, a comprehensive characterization was undertaken on the six types of F 1 males that were the result of the crosses between D. simulans, D. sechellia, and D. mauritiana. With the use of light and electron microscopy, it was shown that while each particular hybrid genotype exhibited a specific sterility phenotype, these phenotypes fell into two distinct classes. The two hybrid genotypes that possessed D. mauritiana X-chromosomes contained spermatogenic defects that caused arrests in premeiotic spermatogenic stages. The other four F 1 hybrids possessed postmeiotic spermatogenic defects. Nonsynchronous cell divisions, underdeveloped mitochondrial derivative-axonemal associations, and microtubule abnormalities were common to all of these hybrids. Each particular postmeiotically defective hybrid genotype demonstrated characteristically distinct profiles in sperm bundle number in addition to characteristic spermiogenic arrests in the furthest developed spermatids. These results in species hybrids contrast with the absence of significant differences in spermatogenic characters between species of this clade. In addition, by utilizing an attached-X cross, we investigated the influence of maternal effects and cytoplasmic factors on the sterility of D. simulans F 1 hybrids and found none. However, we discovered a strain of D. simulans (2119) that caused a large shift in sterility from postmeiotic to premeiotic when crossed to D. sechellia. This suggests that D. simulans is polymorphic for genes involving premeiotic and postmeiotic sterility and that the two types of sterilities between species may have a simple genetic basis. © 1998 The Society for the Study of Evolution.

  4. Construction of "Toxin Complex" in a Mutant Serotype C Strain of Clostridium botulinum Harboring a Defective Neurotoxin Gene.

    PubMed

    Suzuki, Tomonori; Nagano, Thomas; Niwa, Koichi; Uchino, Masataka; Tomizawa, Motohiro; Sagane, Yoshimasa; Watanabe, Toshihiro

    2017-01-01

    A non-toxigenic mutant of the toxigenic serotype C Clostridium botulinum strain Stockholm (C-St), C-N71, does not produce the botulinum neurotoxin (BoNT). However, the original strain C-St produces botulinum toxin complex, in which BoNT is associated with non-toxic non-hemagglutinin (NTNHA) and three hemagglutinin proteins (HA-70, HA-33, and HA-17). Therefore, in this study, we aimed to elucidate the effects of bont gene knockout on the formation of the "toxin complex." Nucleotide sequence analysis revealed that a premature stop codon was introduced in the bont gene, whereas other genes were not affected by this mutation. Moreover, we successfully purified the "toxin complex" produced by C-N71. The "toxin complex" was identified as a mixture of NTNHA/HA-70/HA-17/HA-33 complexes with intact NTNHA or C-terminally truncated NTNHA, without BoNT. These results indicated that knockout of the bont gene does not affect the formation of the "toxin complex." Since the botulinum toxin complex has been shown to play an important role in oral toxin transport in the human and animal body, a non-neurotoxic "toxin complex" of C-N71 may be valuable for the development of an oral drug delivery system.

  5. First-principles investigation of thermodynamic and kinetic properties in titanium-hydrogen system and B2-nickel-alminum compound: Phase stability, point defect complexes and diffusion

    NASA Astrophysics Data System (ADS)

    Xu, Qingchuan

    The purpose of this thesis is to show the technique of predicting thermodynamic and kinetic properties from first-principles using density functional theory (DFT) calculations, cluster expansion methods and Monte Carlo simulations instead of experiments. Two material systems are selected as examples: one is an interstitial system (Ti-H system) and another is a substitutional compound (B2-NiAl alloy). For Ti-H system, this thesis investigated hydride stability, exploring the role of configurational degrees of freedom, zero-point vibrational energy and coherency strains. The tetragonal gamma-TiH phase was predicted to be unstable relative to hcp alpha-Ti and fcc based delta-TiH2. Zero point vibrational energy makes the gamma phase even less stable. The coherency strains between hydride precipitates and alpha-Ti matrix stabilize gamma-TiH relative to alpha-Ti and delta-TiH2. We also found that hydrogen prefers octahedral sites at low hydrogen concentration and tetrahedral sites at high concentration. For B2-NiAl, this thesis investigated the point defects and various diffusion mechanisms. A low barrier collective hop was discovered that could mediate Al diffusion through the anti-structural-bridge (ASB) mechanism. We also found an alternative hop sequence for the migration of a triple defect and a six-jump-cycle than that proposed previously. Going beyond the mean field approximation, we found that the inclusion of interactions among point defects is crucial to predict the concentration of defect complexes. Accounting for interactions among defects and incorporating all diffusion mechanisms proposed for B2-NiAl in Monte Carlo simulation, we calculated tracer diffusion coefficients. For the first time, the relative importance of various diffusion mechanisms is revealed. The ASB hop is the dominant mechanism for Ni in Ni-rich alloy and for Al diffusion in Al-rich alloys. Other mechanisms also play a role to various extents. We also calculated the self and interdiffusion

  6. Loss of Pink1 modulates synaptic mitochondrial bioenergetics in the rat striatum prior to motor symptoms: concomitant complex I respiratory defects and increased complex II-mediated respiration.

    PubMed

    Stauch, Kelly L; Villeneuve, Lance M; Purnell, Phillip R; Ottemann, Brendan M; Emanuel, Katy; Fox, Howard S

    2016-12-01

    Mutations in PTEN-induced putative kinase 1 (Pink1), a mitochondrial serine/threonine kinase, cause a recessive inherited form of Parkinson's disease (PD). Pink1 deletion in rats results in a progressive PD-like phenotype, characterized by significant motor deficits starting at 4 months of age. Despite the evidence of mitochondrial dysfunction, the pathogenic mechanism underlying disease due to Pink1-deficiency remains obscure. Striatal synaptic mitochondria from 3-month-old Pink1-deficient rats were characterized using bioenergetic and mass spectroscopy (MS)-based proteomic analyses. Striatal synaptic mitochondria from Pink1-deficient rats exhibit decreased complex I-driven respiration and increased complex II-mediated respiration compared with wild-type rats. MS-based proteomics revealed 69 of the 811 quantified mitochondrial proteins were differentially expressed between Pink1-deficient rats and controls. Down-regulation of several electron carrier proteins, which shuttle electrons to reduce ubiquinone at complex III, in the Pink1-knockouts suggests disruption of the linkage between fatty acid, amino acid, and choline metabolism and the mitochondrial respiratory system. These results suggest that complex II activity is increased to compensate for loss of electron transfer mechanisms due to reduced complex I activity and loss of electron carriers within striatal nerve terminals early during disease progression. This may contribute to the pathogenesis of PD. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Defective ciliogenesis, embryonic lethality and severe impairment of the Sonic Hedgehog pathway caused by inactivation of the mouse complex A intraflagellar transport gene Ift122/Wdr10, partially overlapping with the DNA repair gene Med1/Mbd4

    PubMed Central

    Cortellino, Salvatore; Wang, Chengbing; Wang, Baolin; Bassi, Maria Rosaria; Caretti, Elena; Champeval, Delphine; Calmont, Amelie; Jarnik, Michal; Burch, John; Zaret, Kenneth; Larue, Lionel; Bellacosa, Alfonso

    2009-01-01

    Primary cilia are assembled and maintained by evolutionarily conserved intraflagellar transport (IFT) proteins that are involved in the coordinated movement of macromolecular cargo from the basal body to the cilium tip and back. The IFT machinery is organized in two structural complexes named complex A and complex B. Recently, inactivation in the mouse germline of Ift genes belonging to complex B revealed a requirement of ciliogenesis, or proteins involved in ciliogenesis, for Sonic Hedgehog (Shh) signaling in mammals. Here we report on a complex A mutant mouse, defective for the Ift122 gene. Ift122-null embryos show multiple developmental defects (exencephaly, situs viscerum inversus, delay in turning, hemorrhage and defects in limb development) that result in lethality. In the node, primary cilia were absent or malformed in homozygous mutant and heterozygous embryos, respectively. Impairment of the Shh pathway was apparent in both neural tube patterning (expansion of motoneurons and rostro-caudal level-dependent contraction or expansion of the dorso-lateral interneurons), and limb patterning (ectrosyndactyly). These phenotypes are distinct from both complex B IFT mutant embryos and embryos defective for the ciliary protein hennin/Arl13b, and suggest reduced levels of both Gli2/Gli3 activator and Gli3 repressor functions. We conclude that complex A and complex B factors play similar but distinct roles in ciliogenesis and Shh/Gli3 signaling. PMID:19000668

  8. Predictors of Clinical Outcome after Reconstruction of Complex Soft Tissue Defects Involving the Achilles Tendon with the Composite Anterolateral Thigh Flap with Vascularized Fascia Lata.

    PubMed

    Jandali, Zaher; Lam, Martin C; Merwart, Benedikt; Möhring, Bernd; Geil, Stephanie; Müller, Klaus; Ionac, Mihai; Jiga, Lucian P

    2018-06-26

     The composite anterolateral thigh flap with vascularized fascia lata (ALT-FL flap) for covering complex soft tissue defects involving the Achilles tendon has shown promising results. The age and body mass index (BMI) are important predictors of clinical outcome after surgical treatment of Achilles tendon ruptures. In this study, we investigate whether these also influence the outcome of patients after Achilles tendon reconstruction using the ALT-FL flap.  Twenty patients (mean age: 55.9 ± 8.7 years) with complex tissue defects involving the Achilles tendon underwent reconstruction with the ALT-FL flap. Both the Achilles tendon Total Rupture Score (ATRS) and the American Orthopaedic Foot and Ankle Society (AOFAS) score were assessed preoperatively and 12 months postoperatively. In addition, postoperative magnetic resonance imaging (MRI) studies and measurements of the ankle range of motion were performed and results compared with existing literature.  All flaps survived and MRI studies confirmed complete anatomical integration of the fascia lata as "neotendon" at the recipient site. In our patient cohort, the age did not correlate with the outcome measurements, whereas the BMI showed significant negative correlation with the postoperative ATRS ( p  < 0.001) and AOFAS scores ( p  < 0.05). The ATRS and AOFAS scores of all patients improved significantly ( p  < 0.001). However, obese patients with a BMI of more than 30 kg/m 2 achieved significant lower ATRS ( p  < 0.001) and AOFAS scores ( p  < 0.01), as well as patients with peripheral artery disease (PAD) ( p  < 0.05). The mean ankle range of motion after ALT-FL flap reconstruction remained statistical insignificant compared with previous avascular or vascularized tendon repairs of the Achilles tendon.  The ALT-FL flap enables reconstruction of complex tissue defects involving the Achilles tendon with good functional results. However, the presence of an increased BMI or PAD, but

  9. Renal oncocytoma characterized by the defective complex I of the respiratory chain boosts the synthesis of the ROS scavenger glutathione.

    PubMed

    Kürschner, Gerrit; Zhang, Qingzhou; Clima, Rosanna; Xiao, Yi; Busch, Jonas Felix; Kilic, Ergin; Jung, Klaus; Berndt, Nikolaus; Bulik, Sascha; Holzhütter, Hermann-Georg; Gasparre, Giuseppe; Attimonelli, Marcella; Babu, Mohan; Meierhofer, David

    2017-12-01

    Renal oncocytomas are rare benign tumors of the kidney and characterized by a deficient complex I (CI) enzyme activity of the oxidative phosphorylation (OXPHOS) system caused by mitochondrial DNA (mtDNA) mutations. Yet, little is known about the underlying molecular mechanisms and alterations of metabolic pathways in this tumor. We compared renal oncocytomas with adjacent matched normal kidney tissues on a global scale by multi-omics approaches, including whole exome sequencing (WES), proteomics, metabolomics, and metabolic pathway simulation. The abundance of proteins localized to mitochondria increased more than 2-fold, the only exception was a strong decrease in the abundance for CI subunits that revealed several pathogenic heteroplasmic mtDNA mutations by WES. We also observed renal oncocytomas to dysregulate main metabolic pathways, shunting away from gluconeogenesis and lipid metabolism. Nevertheless, the abundance of energy carrier molecules such as NAD + , NADH, NADP, ATP, and ADP were significantly higher in renal oncocytomas. Finally, a substantial 5000-fold increase of the reactive oxygen species scavenger glutathione can be regarded as a new hallmark of renal oncocytoma. Our findings demonstrate that renal oncocytomas undergo a metabolic switch to eliminate ATP consuming processes to ensure a sufficient energy supply for the tumor.

  10. Renal oncocytoma characterized by the defective complex I of the respiratory chain boosts the synthesis of the ROS scavenger glutathione

    PubMed Central

    Clima, Rosanna; Xiao, Yi; Busch, Jonas Felix; Kilic, Ergin; Jung, Klaus; Berndt, Nikolaus; Bulik, Sascha; Holzhütter, Hermann-Georg; Gasparre, Giuseppe; Attimonelli, Marcella; Babu, Mohan; Meierhofer, David

    2017-01-01

    Renal oncocytomas are rare benign tumors of the kidney and characterized by a deficient complex I (CI) enzyme activity of the oxidative phosphorylation (OXPHOS) system caused by mitochondrial DNA (mtDNA) mutations. Yet, little is known about the underlying molecular mechanisms and alterations of metabolic pathways in this tumor. We compared renal oncocytomas with adjacent matched normal kidney tissues on a global scale by multi-omics approaches, including whole exome sequencing (WES), proteomics, metabolomics, and metabolic pathway simulation. The abundance of proteins localized to mitochondria increased more than 2-fold, the only exception was a strong decrease in the abundance for CI subunits that revealed several pathogenic heteroplasmic mtDNA mutations by WES. We also observed renal oncocytomas to dysregulate main metabolic pathways, shunting away from gluconeogenesis and lipid metabolism. Nevertheless, the abundance of energy carrier molecules such as NAD+, NADH, NADP, ATP, and ADP were significantly higher in renal oncocytomas. Finally, a substantial 5000-fold increase of the reactive oxygen species scavenger glutathione can be regarded as a new hallmark of renal oncocytoma. Our findings demonstrate that renal oncocytomas undergo a metabolic switch to eliminate ATP consuming processes to ensure a sufficient energy supply for the tumor. PMID:29285300

  11. The "chimeric" trapezius muscle and fasciocutaneous flap (dorsal scapular artery perforator flap): a new design for complex 3-dimensional defects.

    PubMed

    Rozen, Warren M; Fox, Carly M; Leong, James; Morsi, Adel

    2013-11-01

    Multiple variations of the musculocutaneous trapezius flap have been described, each of which use a single composite musculocutaneous unit in their designs. The limitation of such designs is the ability to use the components in a 3-dimensional manner, with only 1 vector existing in the geometry of the musculocutaneous unit. A review of the literature was undertaken with regard to designs of the musculocutaneous trapezius flap, and we present a new technique for flap design. With identification of individual perforators to each of the muscle and fasciocutaneous portions of the trapezius flap, the 2 components can act in a chimeric fashion, able to fill both a deep and complex 3-dimensional space while covering the wound with robust skin. A range of flap designs have been described, including transverse, oblique, and vertical skin paddles accompanying the trapezius muscle. We describe a technique with which a propeller-style skin paddle based on a cutaneous perforator can be raised in any orientation with respect to the underlying muscle. In a presented case, separation of the muscular and fasciocutaneous components of the trapezius flap was able to obliterate dead space around exposed cervicothoracic spinal metalwork and obtain robust wound closure in a patient with previous radiotherapy. This concomitant use of a muscle and fasciocutaneous perforator flap based on a single perforator, a so-called chimeric perforator flap, is a useful modification to trapezius musculocutaneous flap design.

  12. The Role of Defect Complexes in the Magneto-Optical Properties of Rare Earth Doped Gallium Nitride

    NASA Astrophysics Data System (ADS)

    Mitchell, Brandon

    been concluded to contain a nitrogen vacancy (V N) in its immediate structure. The nitrogen vacancy can appear in two symmetries, which has a profound impact on the luminescence and magnetic properties of the sample. The structure of the minority site has also been identified. For both sites, we give substantial evidence that the excitation efficiency of the red Eu emission is improved by the presence of donor-acceptor pairs in the vicinity of the Eu. Furthermore, when Mg was co-doped into GaN:Eu, additional incorporation environments were discovered that show high excitation efficiency at room temperature. These have been attributed to the coupling of Mg-H complexes to the majority Eu site. Electron beam irradiation, indirect and resonant (direct) laser excitation were found to modify these complexes, indicating that vibrational energy alone can trigger the migration of the H, while the presence of additional charges and excess energy controls the type of reconfiguration and the activation of non-radiative decay channels. We identify, experimentally, a two-step process in the dissociation of Mg-H complexes and propose, based on density functional theory, that the presence of minority carriers and the resulting charge states of complexes can also influence this process. In GaN:Er, we have given a more thorough overview of the optical and magneto-optical properties by extending to the 800nm excitation range and drastically improving the signal-to-noise ratio in the magnetic measurements, as well as applying a perpendicular magnetic field. This has allowed us to calculate g-factors for the parallel case, but revealed that the Zeeman interaction is not quite linear for perpendicular magnetic fields. We were able to assign crystal field numbers of mu = 3/2 to two crystal field levels. We have also given strong evidence that the strain in the sample, which results from lattice mismatch, enhances its magnetization, as seen through fluorescence line narrowing and asymmetry

  13. Dysfunction of mitochondria and oxidative stress in the pathogenesis of Alzheimer's disease: on defects in the cytochrome c oxidase complex and aldehyde detoxification.

    PubMed

    Ohta, Shigeo; Ohsawa, Ikuroh

    2006-07-01

    The mitochondrion is an organelle that plays a central role in energy production. It, at the same time, generates reactive oxygen species as by-products. Large-scale epidemiological case-control studies suggest the involvements of dihydrolipoamide succinyltransferase (DLST) of the mitochondrial Krebs cycle and mitochondrial aldehyde dehydrogenase-2 (ALDH2) in Alzheimer's disease (AD). The DLST gene has two gene-products, one of which, a novel gene product MIRTD, mediates the molecular assembly of the cytochrome c oxidase complex whose defect has been a candidate of the causes of AD. Since levels of MIRTD mRNA in the brains of AD patients were significantly low, a decrease in MIRTD could affect energy production. ALDH2, a matrix enzyme, was found to act as a protector against oxidative stress through oxidizing toxic aldehydes, such as 4-hydroxy-2-nonenal, that are spontaneously produced from lipid peroxides. Hence, a decrease in ALDH2 activity is proposed to contribute to AD. Indeed, transgenic mice with low activity of ALDH2 exhibited an age-dependent neurodegeneration accompanying memory loss. Since amyloid beta peptide has been recently shown to be present in neuronal mitochondria to decline energy production and enhance ROS production, it has become possible to link AD more closely with roles of mitochondria in the pathogenesis.

  14. Repairing Nanoparticle Surface Defects.

    PubMed

    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.

  15. Density-functional study on the dopant-segregation mechanism: Chemical potential dependence of dopant-defect complex at Si/SiO2 interface

    NASA Astrophysics Data System (ADS)

    Kawai, Hiroki; Nakasaki, Yasushi; Kanemura, Takahisa; Ishihara, Takamitsu

    2018-04-01

    Dopant segregation at Si/SiO2 interface has been a serious problem in silicon device technology. This paper reports a comprehensive density-functional study on the segregation mechanisms of boron, phosphorous, and arsenic at the Si/SiO2 interface. We found that three kinds of interfacial defects, namely, interstitial oxygen, oxygen vacancy, and silicon vacancy with two oxygen atoms, are stable in the possible chemical potential range. Thus, we consider these defects as trap sites for the dopants. For these defects, the dopant segregation energies, the electrical activities of the trapped dopants, and the kinetic energy barriers of the trapping/detrapping processes are calculated. As a result, trapping at the interstitial oxygen site is indicated to be the most plausible mechanism of the dopant segregation. The interstitial oxygen works as a major trap site since it has a high areal density at the Si/SiO2 interface due to the low formation energy.

  16. Congenital Defects.

    ERIC Educational Resources Information Center

    Goldman, Allen S.; And Others

    There are two general categories (not necessarily mutually exclusive) of congenital defects: (1) abnormalities that have an hereditary basis, such as single and multiple genes, or chromosomal abberration; and (2) abnormalities that are caused by nonhereditary factors, such as malnutrition, maternal disease, radiation, infections, drugs, or…

  17. Defect mapping system

    DOEpatents

    Sopori, Bhushan L.

    1995-01-01

    Apparatus for detecting and mapping defects in the surfaces of polycrystalline materials in a manner that distinguishes dislocation pits from grain boundaries includes a laser for illuminating a wide spot on the surface of the material, a light integrating sphere with apertures for capturing light scattered by etched dislocation pits in an intermediate range away from specular reflection while allowing light scattered by etched grain boundaries in a near range from specular reflection to pass through, and optical detection devices for detecting and measuring intensities of the respective intermediate scattered light and near specular scattered light. A center blocking aperture or filter can be used to screen out specular reflected light, which would be reflected by nondefect portions of the polycrystalline material surface. An X-Y translation stage for mounting the polycrystalline material and signal processing and computer equipment accommodate rastor mapping, recording, and displaying of respective dislocation and grain boundary defect densities. A special etch procedure is included, which prepares the polycrystalline material surface to produce distinguishable intermediate and near specular light scattering in patterns that have statistical relevance to the dislocation and grain boundary defect densities.

  18. Defect mapping system

    DOEpatents

    Sopori, B.L.

    1995-04-11

    Apparatus for detecting and mapping defects in the surfaces of polycrystalline materials in a manner that distinguishes dislocation pits from grain boundaries includes a laser for illuminating a wide spot on the surface of the material, a light integrating sphere with apertures for capturing light scattered by etched dislocation pits in an intermediate range away from specular reflection while allowing light scattered by etched grain boundaries in a near range from specular reflection to pass through, and optical detection devices for detecting and measuring intensities of the respective intermediate scattered light and near specular scattered light. A center blocking aperture or filter can be used to screen out specular reflected light, which would be reflected by nondefect portions of the polycrystalline material surface. An X-Y translation stage for mounting the polycrystalline material and signal processing and computer equipment accommodate rastor mapping, recording, and displaying of respective dislocation and grain boundary defect densities. A special etch procedure is included, which prepares the polycrystalline material surface to produce distinguishable intermediate and near specular light scattering in patterns that have statistical relevance to the dislocation and grain boundary defect densities. 20 figures.

  19. Staged curative treatment of a complex direct carotid-cavernous fistula with a large arterial defect and an 'oversized' internal carotid artery.

    PubMed

    Bender, Matthew T; Lin, Li-Mei; Coon, Alexander L; Colby, Geoffrey P

    2017-06-14

    This is a case of a high-flow, post-traumatic direct carotid-cavernous fistula with a widened arterial defect and a large-diameter internal carotid artery (ICA). The unique aspect of this case is the oversized ICA, >8mm in diameter, which is both a pathological and a therapeutic challenge, given the lack of available neuroendovascular devices for full vessel reconstruction. We present a planned two-stage embolisation paradigm for definitive treatment. Transarterial coil embolisation is performed as the first stage to disconnect the fistula and normalise flow in the ICA. A 3-month recovery period is then allowed for reduction in carotid diameter. Repair of the large vessel defect and pseudoaneurysm is performed as a second stage in a delayed fashion with a flow-diverting device. Follow-up angiography at 6 months demonstrates obliteration of the fistula and curative ICA reconstruction to a diameter <5mm. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

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

    PubMed

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

    2014-04-07

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

  1. Defective Expression of the Mitochondrial-tRNA Modifying Enzyme GTPBP3 Triggers AMPK-Mediated Adaptive Responses Involving Complex I Assembly Factors, Uncoupling Protein 2, and the Mitochondrial Pyruvate Carrier.

    PubMed

    Martínez-Zamora, Ana; Meseguer, Salvador; Esteve, Juan M; Villarroya, Magda; Aguado, Carmen; Enríquez, J Antonio; Knecht, Erwin; Armengod, M-Eugenia

    2015-01-01

    GTPBP3 is an evolutionary conserved protein presumably involved in mitochondrial tRNA (mt-tRNA) modification. In humans, GTPBP3 mutations cause hypertrophic cardiomyopathy with lactic acidosis, and have been associated with a defect in mitochondrial translation, yet the pathomechanism remains unclear. Here we use a GTPBP3 stable-silencing model (shGTPBP3 cells) for a further characterization of the phenotype conferred by the GTPBP3 defect. We experimentally show for the first time that GTPBP3 depletion is associated with an mt-tRNA hypomodification status, as mt-tRNAs from shGTPBP3 cells were more sensitive to digestion by angiogenin than tRNAs from control cells. Despite the effect of stable silencing of GTPBP3 on global mitochondrial translation being rather mild, the steady-state levels and activity of Complex I, and cellular ATP levels were 50% of those found in the controls. Notably, the ATPase activity of Complex V increased by about 40% in GTPBP3 depleted cells suggesting that mitochondria consume ATP to maintain the membrane potential. Moreover, shGTPBP3 cells exhibited enhanced antioxidant capacity and a nearly 2-fold increase in the uncoupling protein UCP2 levels. Our data indicate that stable silencing of GTPBP3 triggers an AMPK-dependent retrograde signaling pathway that down-regulates the expression of the NDUFAF3 and NDUFAF4 Complex I assembly factors and the mitochondrial pyruvate carrier (MPC), while up-regulating the expression of UCP2. We also found that genes involved in glycolysis and oxidation of fatty acids are up-regulated. These data are compatible with a model in which high UCP2 levels, together with a reduction in pyruvate transport due to the down-regulation of MPC, promote a shift from pyruvate to fatty acid oxidation, and to an uncoupling of glycolysis and oxidative phosphorylation. These metabolic alterations, and the low ATP levels, may negatively affect heart function.

  2. Putting 3D modelling and 3D printing into practice: virtual surgery and preoperative planning to reconstruct complex post-traumatic skeletal deformities and defects

    PubMed Central

    Tetsworth, Kevin; Block, Steve; Glatt, Vaida

    2017-01-01

    3D printing technology has revolutionized and gradually transformed manufacturing across a broad spectrum of industries, including healthcare. Nowhere is this more apparent than in orthopaedics with many surgeons already incorporating aspects of 3D modelling and virtual procedures into their routine clinical practice. As a more extreme application, patient-specific 3D printed titanium truss cages represent a novel approach for managing the challenge of segmental bone defects. This review illustrates the potential indications of this innovative technique using 3D printed titanium truss cages in conjunction with the Masquelet technique. These implants are custom designed during a virtual surgical planning session with the combined input of an orthopaedic surgeon, an orthopaedic engineering professional and a biomedical design engineer. The ability to 3D model an identical replica of the original intact bone in a virtual procedure is of vital importance when attempting to precisely reconstruct normal anatomy during the actual procedure. Additionally, other important factors must be considered during the planning procedure, such as the three-dimensional configuration of the implant. Meticulous design is necessary to allow for successful implantation through the planned surgical exposure, while being aware of the constraints imposed by local anatomy and prior implants. This review will attempt to synthesize the current state of the art as well as discuss our personal experience using this promising technique. It will address implant design considerations including the mechanical, anatomical and functional aspects unique to each case. PMID:28220752

  3. Design and Fabrication of Complex Scaffolds for Bone Defect Healing: Combined 3D Plotting of a Calcium Phosphate Cement and a Growth Factor-Loaded Hydrogel.

    PubMed

    Ahlfeld, Tilman; Akkineni, Ashwini Rahul; Förster, Yvonne; Köhler, Tino; Knaack, Sven; Gelinsky, Michael; Lode, Anja

    2017-01-01

    Additive manufacturing enables the fabrication of scaffolds with defined architecture. Versatile printing technologies such as extrusion-based 3D plotting allow in addition the incorporation of biological components increasing the capability to restore functional tissues. We have recently described the fabrication of calcium phosphate cement (CPC) scaffolds by 3D plotting of an oil-based CPC paste under mild conditions. In the present study, we have developed a strategy for growth factor loading based on multichannel plotting: a biphasic scaffold design was realised combining CPC with VEGF-laden, highly concentrated hydrogel strands. As hydrogel component, alginate and an alginate-gellan gum blend were evaluated; the blend exhibited a more favourable VEGF release profile and was chosen for biphasic scaffold fabrication. After plotting, two-step post-processing was performed for both, hydrogel crosslinking and CPC setting, which was shown to be compatible with both materials. Finally, a scaffold was designed and fabricated which can be applied for testing in a rat critical size femur defect. Optimization of CPC plotting enabled the fabrication of highly resolved structures with strand diameters of only 200 µm. Micro-computed tomography revealed a precise strand arrangement and an interconnected pore space within the biphasic scaffold even in swollen state of the hydrogel strands.

  4. Putting 3D modelling and 3D printing into practice: virtual surgery and preoperative planning to reconstruct complex post-traumatic skeletal deformities and defects.

    PubMed

    Tetsworth, Kevin; Block, Steve; Glatt, Vaida

    2017-01-01

    3D printing technology has revolutionized and gradually transformed manufacturing across a broad spectrum of industries, including healthcare. Nowhere is this more apparent than in orthopaedics with many surgeons already incorporating aspects of 3D modelling and virtual procedures into their routine clinical practice. As a more extreme application, patient-specific 3D printed titanium truss cages represent a novel approach for managing the challenge of segmental bone defects. This review illustrates the potential indications of this innovative technique using 3D printed titanium truss cages in conjunction with the Masquelet technique. These implants are custom designed during a virtual surgical planning session with the combined input of an orthopaedic surgeon, an orthopaedic engineering professional and a biomedical design engineer. The ability to 3D model an identical replica of the original intact bone in a virtual procedure is of vital importance when attempting to precisely reconstruct normal anatomy during the actual procedure. Additionally, other important factors must be considered during the planning procedure, such as the three-dimensional configuration of the implant. Meticulous design is necessary to allow for successful implantation through the planned surgical exposure, while being aware of the constraints imposed by local anatomy and prior implants. This review will attempt to synthesize the current state of the art as well as discuss our personal experience using this promising technique. It will address implant design considerations including the mechanical, anatomical and functional aspects unique to each case. © The Authors, published by EDP Sciences, 2017.

  5. Neural Tube Defects

    MedlinePlus

    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 ...

  6. Single Ventricle Defects

    MedlinePlus

    ... Your Risk • Symptoms & Diagnosis • Care & Treatment • Tools & Resources Web Booklets on Congenital Heart Defects These online publications ... to you or your child’s defect and concerns. Web Booklet: Adults With Congenital Heart Defects Web Booklet: ...

  7. Nuclear Pasta: Topology and Defects

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  8. Facts about Birth Defects

    MedlinePlus

    ... Defects Language: English (US) Español (Spanish) Recommend on Facebook Tweet Share Compartir On This Page Birth Defects are Common Identifying Birth Defects Causes Prevention References Birth defects are common, costly, and critical conditions that affect 1 in every 33 babies born in the ...

  9. The Na+ transport in gram-positive bacteria defect in the Mrp antiporter complex measured with 23Na nuclear magnetic resonance.

    PubMed

    Górecki, Kamil; Hägerhäll, Cecilia; Drakenberg, Torbjörn

    2014-01-15

    (23)Na nuclear magnetic resonance (NMR) has previously been used to monitor Na(+) translocation across membranes in gram-negative bacteria and in various other organelles and liposomes using a membrane-impermeable shift reagent to resolve the signals resulting from internal and external Na(+). In this work, the (23)Na NMR method was adapted for measurements of internal Na(+) concentration in the gram-positive bacterium Bacillus subtilis, with the aim of assessing the Na(+) translocation activity of the Mrp (multiple resistance and pH) antiporter complex, a member of the cation proton antiporter-3 (CPA-3) family. The sodium-sensitive growth phenotype observed in a B. subtilis strain with the gene encoding MrpA deleted could indeed be correlated to the inability of this strain to maintain a lower internal Na(+) concentration than an external one. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Reconstruction of acquired oromandibular defects.

    PubMed

    Fernandes, Rui P; Yetzer, Jacob G

    2013-05-01

    Acquired defects of the mandible resulting from trauma, infection, osteoradionecrosis, and ablative surgery of the oral cavity and lower face are particularly debilitating. Familiarity with mandibular and cervical anatomy is crucial in achieving mandibular reconstruction. The surgeon must evaluate which components of the hard and soft tissue are missing in selecting a method of reconstruction. Complexity of mandibular reconstruction ranges from simple rigid internal fixation to microvascular free tissue transfer, depending on defect- and patient-related factors. Modern techniques for microvascular tissue transfer provide a wide array of reconstructive options that can be tailored to patients' specific needs. Copyright © 2013 Elsevier Inc. All rights reserved.

  11. Creating Knock-outs of Conserved Oligomeric Golgi complex subunits using CRISPR-mediated gene editing paired with a selection strategy based on glycosylation defects associated with impaired COG complex function

    PubMed Central

    Blackburn, Jessica Bailey; Lupashin, Vladimir V.

    2017-01-01

    Summary The Conserved Oligomeric Golgi (COG) complex is a key evolutionally conserved multisubunit protein machinery that regulates tethering and fusion of intra-Golgi transport vesicles. The Golgi apparatus specifically promotes sorting and complex glycosylation of glycoconjugates. Without proper glycosylation and processing, proteins and lipids will be mislocalized and/or have impaired function. The Golgi glycosylation machinery is kept in homeostasis by a careful balance of anterograde and retrograde trafficking to ensure proper localization of the glycosylation enzymes and their substrates. This balance, like other steps of membrane trafficking, is maintained by vesicle trafficking machinery that includes COPI vesicular coat proteins, SNAREs, Rabs, and both coiled-coil and multi-subunit vesicular tethers. COG complex interacts with other membrane trafficking components and is essential for proper localization of Golgi glycosylation machinery. Here we describe using CRISPR-mediated gene editing coupled with a phenotype-based selection strategy directly linked to the COG complex’s role in glycosylation homeostasis to obtain COG complex subunit knock-outs (KOs). This has resulted in clonal KOs for each COG subunit in HEK293T cells and gives the ability to further probe the role of the COG complex in Golgi homeostasis. PMID:27632008

  12. A novel regulatory defect in the branched-chain α-keto acid dehydrogenase complex due to a mutation in the PPM1K gene causes a mild variant phenotype of maple syrup urine disease.

    PubMed

    Oyarzabal, Alfonso; Martínez-Pardo, Mercedes; Merinero, Begoña; Navarrete, Rosa; Desviat, Lourdes R; Ugarte, Magdalena; Rodríguez-Pombo, Pilar

    2013-02-01

    This article describes a hitherto unreported involvement of the phosphatase PP2Cm, a recently described member of the branched-chain α-keto acid dehydrogenase (BCKDH) complex, in maple syrup urine disease (MSUD). The disease-causing mutation was identified in a patient with a mild variant phenotype, involving a gene not previously associated with MSUD. SNP array-based genotyping showed a copy-neutral homozygous pattern for chromosome 4 compatible with uniparental isodisomy. Mutation analysis of the candidate gene, PPM1K, revealed a homozygous c.417_418delTA change predicted to result in a truncated, unstable protein. No PP2Cm mutant protein was detected in immunocytochemical or Western blot expression analyses. The transient expression of wild-type PPM1K in PP2Cm-deficient fibroblasts recovered 35% of normal BCKDH activity. As PP2Cm has been described essential for cell survival, apoptosis and metabolism, the impact of its deficiency on specific metabolic stress variables was evaluated in PP2Cm-deficient fibroblasts. Increases were seen in ROS levels along with the activation of specific stress-signaling MAP kinases. Similar to that described for the pyruvate dehydrogenase complex, a defect in the regulation of BCKDH caused the aberrant metabolism of its substrate, contributing to the patient's MSUD phenotype--and perhaps others. © 2012 WILEY PERIODICALS, INC.

  13. Integrated strategy for identifying minor components in complex samples combining mass defect, diagnostic ions and neutral loss information based on ultra-performance liquid chromatography-high resolution mass spectrometry platform: Folium Artemisiae Argyi as a case study.

    PubMed

    Ren, Dabing; Ran, Lu; Yang, Chong; Xu, Meilin; Yi, Lunzhao

    2018-05-18

    Ultra-performance liquid chromatography coupled to high-resolution mass spectrometry (UPLC-HRMS) has been used as a powerful tool to profile chemicals in traditional Chinese medicines. However, identification of potentially bioactive compounds is still a challenging work because of the large amount of information contained in the raw UPLC-HRMS data. Especially the ubiquitous matrix interference makes it more difficult to characterize the minor components. Therefore, rapid recognition and efficient extraction of the corresponding parent ions is critically important for identifying the attractive compounds in complex samples. Herein, we propose an integrated filtering strategy to remove un-related or interference MS 1 ions from the raw UPLC-HRMS data, which helps to retain the MS features of the target components and expose the compounds of interest as effective as possible. The proposed strategy is based on the use of a combination of different filtering methods, including nitrogen rule, mass defect, and neutral loss/diagnostic fragment ions filtering. The strategy was validated by rapid screening and identification of 16 methoxylated flavonoids and 55 chlorogenic acids analogues from the raw UPLC-HRMS dataset of Folium Artemisiae Argyi. Particularly, successful detection of several minor components indicated that the integrated strategy has obvious advantages over individual filtering methods, and it can be used as a promising method for screening and identifying compounds from complex samples, such as herbal medicines. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. The AtRbx1 protein is part of plant SCF complexes, and its down-regulation causes severe growth and developmental defects.

    PubMed

    Lechner, Esther; Xie, Daoxin; Grava, Sandrine; Pigaglio, Emmanuelle; Planchais, Severine; Murray, James A H; Parmentier, Yves; Mutterer, Jerome; Dubreucq, Bertrand; Shen, Wen-Hui; Genschik, Pascal

    2002-12-20

    Recently in yeast and animal cells, one particular class of ubiquitin ligase (E3), called the SCF, was demonstrated to regulate diverse processes including cell cycle and development. In plants SCF-dependent proteolysis is also involved in different developmental and hormonal regulations. To further investigate the function of SCF, we characterized at the molecular level the Arabidopsis RING-H2 finger protein AtRbx1. We demonstrated that the plant gene is able to functionally complement a yeast knockout mutant strain and showed that AtRbx1 protein interacts physically with at least two members of the Arabidopsis cullin family (AtCul1 and AtCul4). AtRbx1 also associates with AtCul1 and the Arabidopsis SKP1-related proteins in planta, indicating that it is part of plant SCF complexes. AtRbx1 mRNAs accumulate in various tissues of the plant, but at higher levels in tissues containing actively dividing cells. Finally to study the function of the gene in planta, we either overexpressed AtRbx1 or reduced its expression by a dsRNA strategy. Down-regulation of AtRbx1 impaired seedling growth and development, indicating that the gene is essential in plants. Furthermore, the AtRbx1-silenced plants showed a reduced level of AtCul1 protein, but accumulated higher level of cyclin D3.

  15. Defects formation and wave emitting from defects in excitable media

    NASA Astrophysics Data System (ADS)

    Ma, Jun; Xu, Ying; Tang, Jun; Wang, Chunni

    2016-05-01

    Abnormal electrical activities in neuronal system could be associated with some neuronal diseases. Indeed, external forcing can cause breakdown even collapse in nervous system under appropriate condition. The excitable media sometimes could be described by neuronal network with different topologies. The collective behaviors of neurons can show complex spatiotemporal dynamical properties and spatial distribution for electrical activities due to self-organization even from the regulating from central nervous system. Defects in the nervous system can emit continuous waves or pulses, and pacemaker-like source is generated to perturb the normal signal propagation in nervous system. How these defects are developed? In this paper, a network of neurons is designed in two-dimensional square array with nearest-neighbor connection type; the formation mechanism of defects is investigated by detecting the wave propagation induced by external forcing. It is found that defects could be induced under external periodical forcing under the boundary, and then the wave emitted from the defects can keep balance with the waves excited from external forcing.

  16. Feasibility of a Team Approach to Complex Congenital Heart Defect Neurodevelopmental Follow-Up: Early Experience of a Combined Cardiology/Neonatal Intensive Care Unit Follow-Up Program.

    PubMed

    Chorna, Olena; Baldwin, H Scott; Neumaier, Jamie; Gogliotti, Shirley; Powers, Deborah; Mouvery, Amanda; Bichell, David; Maitre, Nathalie L

    2016-07-01

    Infants with complex congenital heart disease are at high risk for poor neurodevelopmental outcomes. However, implementation of dedicated congenital heart disease follow-up programs presents important infrastructure, personnel, and resource challenges. We present the development, implementation, and retrospective review of 1- and 2-year outcomes of a Complex Congenital Heart Defect Neurodevelopmental Follow-Up program. This program was a synergistic approach between the Pediatric Cardiology, Cardiothoracic Surgery, Pediatric Intensive Care, and Neonatal Intensive Care Unit Follow-Up teams to provide a feasible and responsible utilization of existing infrastructure and personnel, to develop and implement a program dedicated to children with congenital heart disease. Trained developmental testers administered the Ages and Stages Questionnaire-3 over the phone to the parents of all referred children at least once between 6 and 12 months' corrected age. At 18 months' corrected age, all children were scheduled in the Neonatal Intensive-Care Unit Follow-Up Clinic for a visit with standardized neurological exams, Bayley III, multidisciplinary therapy evaluations and continued follow-up. Of the 132 patients identified in the Cardiothoracic Surgery database and at discharge from the hospital, a total number of 106 infants were reviewed. A genetic syndrome was identified in 23.4% of the population. Neuroimaging abnormalities were identified in 21.7% of the cohort with 12.8% having visibly severe insults. As a result, 23 (26.7%) received first-time referrals for early intervention services, 16 (13.8%) received referrals for new services in addition to their existing ones. We concluded that utilization of existing resources in collaboration with established programs can ensure targeted neurodevelopmental follow-up for all children with complex congenital heart disease. © 2016 American Heart Association, Inc.

  17. Box 6: Nanoscale Defects

    NASA Astrophysics Data System (ADS)

    Alves, Eduardo; Breese, Mark

    Defects affect virtually all properties of crystalline materials, and their role is magnified in nanoscale structures. In this box we describe the different type of defects with particular emphasis on point and linear defects. Above zero Kelvin all real materials have a defect population within their structure, which affects either their crystalline, electronic or optical properties. It is common to attribute a negative connotation to the presence of defects. However, a perfect silicon crystal or any other defect-free semiconductor would have a limited functionality and might even be useless.

  18. Clues from defect photochemistry

    NASA Astrophysics Data System (ADS)

    De Angelis, Filippo; Petrozza, Annamaria

    2018-05-01

    Charge carriers in metal halide perovskites seem to be only marginally affected by defect-related trap states. Filippo De Angelis and Annamaria Petrozza suggest that the key to this behaviour lies in the redox chemistry of halide defects.

  19. Atrioventricular Canal Defect

    MedlinePlus

    ... birth (congenital). The condition is often associated with Down syndrome. Atrioventricular canal defect allows extra blood to flow ... baby's heart is developing. Some factors, such as Down syndrome, might increase the risk of atrioventricular canal defect. ...

  20. Elementary defects in graphane

    NASA Astrophysics Data System (ADS)

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

    2017-07-01

    The main zero-dimensional defects in graphane, a completely hydrogenated single-layer graphene, having the chair-type conformation have been numerically simulated. The hydrogen and carbon-hydrogen vacancies, Stone-Wales defect, and "transmutation defect" resulting from the simultaneous hoppings of two hydrogen atoms between the neighboring carbon atoms have been considered. The energies of formations of these defects have been calculated and their effect on the electronic structure, phonon spectra, and Young modulus has been studied.

  1. Project THEMIS: A Center for Remote Sensing.

    DTIC Science & Technology

    This report summarizes the technical work accomplished under Project THEMIS, A Center for Remote Sensing at the University of Kansas during the...period 16 September 1967 through 15 September 1973. The highlights of the four major areas forming the remote sensing system are presented. A detailed description of the latest radar spectrometer results is presented.

  2. Defect interactions in GaAs single crystals

    NASA Technical Reports Server (NTRS)

    Gatos, H. C.; Lagowski, J.

    1984-01-01

    The two-sublattice structural configuration of GaAs and deviations from stoichiometry render the generation and interaction of electrically active point defects (and point defect complexes) critically important for device applications and very complex. Of the defect-induced energy levels, those lying deep into the energy band are very effective lifetime ""killers". The level 0.82 eV below the condition band, commonly referred to as EL2, is a major deep level, particularly in melt-grown GaAs. This level is associated with an antisite defect complex (AsGa - VAS). Possible mechanisms of its formation and its annihilation were further developed.

  3. Nanocarbon: Defect Architectures and Properties

    NASA Astrophysics Data System (ADS)

    Vuong, Amanda

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

  4. Point Defects in Oxides: Tailoring Materials Through Defect Engineering

    NASA Astrophysics Data System (ADS)

    Tuller, Harry L.; Bishop, Sean R.

    2011-08-01

    Optimization of electrical, optical, mechanical, and other properties of many advanced, functional materials today relies on precise control of point defects. This article illustrates the progress that has been made in elucidating the often complex equilibria exhibited by many materials by examining two recently well-characterized model systems, TlBr for radiation detection and PrxCe1-xO2-δ, of potential interest in solid-oxide fuel cells. The interplay between material composition, electrical conductivity, and mechanical properties (electrochemomechanics) is discussed, and implications in these relations, for example, enhancing electrical properties through large mechanical strains, are described. The impact of space charge and strain fields at interfaces, particularly important in nanostructure materials, is also emphasized. Key experimental techniques useful in characterizing bulk and surface defects are summarized and reviewed.

  5. Native defects in Tl 6SI 4: Density functional calculations

    DOE PAGES

    Shi, Hongliang; Du, Mao -Hua

    2015-05-05

    In this study, Tl 6SI 4 is a promising room-temperature semiconductor radiation detection material. Here, we report density functional calculations of native defects and dielectric properties of Tl 6SI 4. Formation energies and defect levels of native point defects and defect complexes are calculated. Donor-acceptor defect complexes are shown to be abundant in Tl 6SI 4. High resistivity can be obtained by Fermi level pinning by native donor and acceptor defects. Deep donors that are detrimental to electron transport are identified and methods to mitigate such problem are discussed. Furthermore, we show that mixed ionic-covalent character of Tl 6SI 4more » gives rise to enhanced Born effective charges and large static dielectric constant, which provides effective screening of charged defects and impurities.« less

  6. Reconstruction of maxillectomy and midfacial defects with free tissue transfer.

    PubMed

    Santamaria, Eric; Cordeiro, Peter G

    2006-11-01

    The maxillary bones are part of the midfacial skeleton and are closely related to the eyeglobe, nasal airway, and oral cavity. Together with the overlying soft tissues, the two maxillae are responsible to a large extent for facial contour. Maxillectomy defects become more complex when critical structures such as the orbit, globe, and cranial base are resected, and reconstruction with distant tissues become essential. In this article, we describe a classification system and algorithm for reconstruction of these complex defects using various pedicled and free flaps. Most defects that involve resection of the maxilla and adjacent soft tissues may be classified into one of the following four types: Type I defects, Limited maxillectomy; Type II defects, Subtotal maxillectomy; Type III defects, Total maxillectomy; and Type IV defects, Orbitomaxillectomy. Using this classification, reconstruction of maxillectomy and midfacial defects may be approached considering the relationship between volume and surface area requirements, that is, addressing the bony defect first, followed by assessment of the associated soft tissue, skin, palate, and cheek-lining deficits. In our experience, most complex maxillectomy defects are best reconstructed using free tissue transfer. The rectus abdominis and radial forearm free flap in combination with immediate bone grafting or as an osteocutaneous flap reliably provide the best aesthetic and functional results. A temporalis muscle pedicled flap is used for reconstruction of maxillectomy defects only in those patients who are not candidates for a microsurgical procedure.

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

    NASA Astrophysics Data System (ADS)

    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

  8. Multiscale simulations of defect dipole-enhanced electromechanical coupling at dilute defect concentrations

    NASA Astrophysics Data System (ADS)

    Liu, Shi; Cohen, R. E.

    2017-08-01

    The role of defects in solids of mixed ionic-covalent bonds such as ferroelectric oxides is complex. Current understanding of defects on ferroelectric properties at the single-defect level remains mostly at the empirical level, and the detailed atomistic mechanisms for many defect-mediated polarization-switching processes have not been convincingly revealed quantum mechanically. We simulate the polarization-electric field (P-E) and strain-electric field (ɛ-E) hysteresis loops for BaTiO3 in the presence of generic defect dipoles with large-scale molecular dynamics and provide a detailed atomistic picture of the defect dipole-enhanced electromechanical coupling. We develop a general first-principles-based atomistic model, enabling a quantitative understanding of the relationship between macroscopic ferroelectric properties and dipolar impurities of different orientations, concentrations, and dipole moments. We find that the collective orientation of dipolar defects relative to the external field is the key microscopic structure feature that strongly affects materials hardening/softening and electromechanical coupling. We show that a small concentration (≈0.1 at. %) of defect dipoles dramatically improves electromechanical responses. This offers the opportunity to improve the performance of inexpensive polycrystalline ferroelectric ceramics through defect dipole engineering for a range of applications including piezoelectric sensors, actuators, and transducers.

  9. Defects in hardwood timber

    Treesearch

    Roswell D. Carpenter; David L. Sonderman; Everette D. Rast; Martin J. Jones

    1989-01-01

    Includes detailed information on all common defects that may aRect hardwood trees and logs. Relationships between manufactured products and those forms of round material to be processed from the tree for conversion into marketable products are discussed. This handbook supersedes Agriculture Handbook No. 244, Grade defects in hardwood timber and logs, by C.R. Lockard, J...

  10. Reconstruction of Peripelvic Oncologic Defects.

    PubMed

    Weichman, Katie E; Matros, Evan; Disa, Joseph J

    2017-10-01

    After studying this article, the participant should be able to: 1. Understand the anatomy of the peripelvic area. 2. Understand the advantages and disadvantages of performing peripelvic reconstruction in patients undergoing oncologic resection. 3. Select the appropriate local, pedicled, or free-flap reconstruction based on the location of the defect and donor-site characteristics. Peripelvic reconstruction most commonly occurs in the setting of oncologic ablative surgery. The peripelvic area contains several distinct reconstructive regions, including vagina, vulva, penis, and scrotum. Each area provides unique reconstructive considerations. In addition, prior or future radiation therapy or chemotherapy along with cancer cachexia can increase the complexity of reconstruction.

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

    PubMed

    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.

  12. Defects in Calcite.

    DTIC Science & Technology

    1991-05-13

    AD-A245 645 A TRIDENT SCHOLAR PROJECT REPORT NO. 181 "DEFECTS IN CALCITE " DTTC %N FEB 5-1912 UNITED STATES NAVAL ACADEMY ANNAPOLIS, MARYLAND 92-02841...report; no. 181 (1991) "DEFECTS IN CALCITE " A Trident Scholar Project Report by Midshipman Anthony J. Kotarski, Class of 1991 U. S. Naval Academy Annapolis...REPORT TYPE AND DATES COVERED 13 May 1991 Final 1990/91 . TITLE AND SUBTITLE s. FUNDING NUMBERS DEFECTS IN CALCITE 6. AUTHOR(S) Anthony J. Kotarski 7

  13. Birth Defects Data and Statistics

    MedlinePlus

    ... Septal Defect Atrioventricular Septal Defect Coarctation of the Aorta D-Transposition of the Great Arteries Hypoplastic Left ... Syndrome Disorders Gastroschisis Heart Defects Coarctation of the Aorta Hypoplastic left heart syndrome Tetralogy of Fallot Other ...

  14. Phonon-assisted changes in charge states of deep level defects in germanium

    NASA Astrophysics Data System (ADS)

    Markevich, A. V.; Litvinov, V. V.; Emtsev, V. V.; Markevich, V. P.; Peaker, A. R.

    2006-04-01

    Electronic processes associated with changes in the charge states of the vacancy-oxygen center (VO or A center) and vacancy-group-V-impurity atom (P, As, Sb or Bi) pairs (E centers) in irradiated germanium crystals have been studied using deep level transient spectroscopy (DLTS), high-resolution Laplace DLTS and Hall effect measurements. It is found that the electron emission and capture processes related to transitions between the doubly and the singly negatively charged states of the A center and the E centers in Ge are phonon-assisted, i.e., they are accompanied by significant vibrations and re-arrangements of atoms in the vicinity of the defects. Manifestations of the phonon involvements are: (i) temperature-dependent electron capture cross-sections which are well described in the frame of the multi-phonon-assisted capture model; (ii) large changes in entropy related to the ionization of the defects and, associated with these, temperature-dependent positions of energy levels; and (iii) electron emission via phonon-assisted tunneling upon the application of electric field. These effects have been considered in detail for the vacancy-oxygen and the vacancy-donor complexes. On the basis of a combined analysis of the electronic processes a configuration-coordinate diagram of the acceptor states of the A and E centers is plotted. It is found that changes in the entropy of ionization and the energy for electron emission for these traps follow the empirical Meyer-Neldel rule. A model based on multi-phonon-assisted carrier emission from defects is adapted for the explanation of the origin of this rule for the case of electronic processes in Ge.

  15. Endocardial cushion defect

    MedlinePlus

    ... 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- ...

  16. Congenital platelet function defects

    MedlinePlus

    Platelet storage pool disorder; Glanzmann's thrombasthenia; Bernard-Soulier syndrome; Platelet function defects - congenital ... This disorder may also cause severe bleeding. Platelet storage pool disorder (also called platelet secretion disorder) occurs ...

  17. Effect of Bearing Defects

    DTIC Science & Technology

    1974-12-01

    defect types were tested at various levels: Comet- Tail, Dig-Nick, Dirt Brinell, Grind-Skip Lines, Impingement, Orange Peel , Pit, Scratch and "Liney...Shallow irregular indentation of surface. <.0015 max. dim. -(<.0008)*’ Otange Peel Pebbly appearance of raceway surface. Small ** Comet Tail Pit...scratch; dig-nick; impingement; grind-skip lines; and orange peel . The data obtained indicated that these defects in most cases, affected bearing

  18. Analysis of the defect clusters in congruent lithium tantalate

    NASA Astrophysics Data System (ADS)

    Vyalikh, Anastasia; Zschornak, Matthias; Köhler, Thomas; Nentwich, Melanie; Weigel, Tina; Hanzig, Juliane; Zaripov, Ruslan; Vavilova, Evgenia; Gemming, Sibylle; Brendler, Erica; Meyer, Dirk C.

    2018-01-01

    A wide range of technological applications of lithium tantalate (LT) is closely related to the defect chemistry. In literature, several intrinsic defect models have been proposed. Here, using a combinational approach based on DFT and solid-state NMR, we demonstrate that distribution of electric field gradients (EFGs) can be employed as a fingerprint of a specific defect configuration. Analyzing the distribution of 7Li EFGs, the FT-IR and electron spin resonance (ESR) spectra, and the 7Li spin-lattice relaxation behavior, we have found that the congruent LT samples provided by two manufacturers show rather different defect concentrations and distributions although both were grown by the Czochralski method. After thermal treatment hydrogen out-diffusion and homogeneous distribution of other defects have been observed by ESR, NMR, and FT-IR. The defect structure in one of two congruent LT crystals after annealing has been identified and proved by defect formation energy considerations, whereas the more complex defect configuration, including the presence of extrinsic defects, has been suggested for the other LT sample. The approach of searching the EFG fingerprints from DFT calculations in NMR spectra can be applied for identifying the defect clusters in other complex oxides.

  19. Defect classification in sparsity-based structural health monitoring

    NASA Astrophysics Data System (ADS)

    Golato, Andrew; Ahmad, Fauzia; Santhanam, Sridhar; Amin, Moeness G.

    2017-05-01

    Guided waves have gained popularity in structural health monitoring (SHM) due to their ability to inspect large areas with little attenuation, while providing rich interactions with defects. For thin-walled structures, the propagating waves are Lamb waves, which are a complex but well understood type of guided waves. Recent works have cast the defect localization problem of Lamb wave based SHM within the sparse reconstruction framework. These methods make use of a linear model relating the measurements with the scene reflectivity under the assumption of point-like defects. However, most structural defects are not perfect points but tend to assume specific forms, such as surface cracks or internal cracks. Knowledge of the "type" of defects is useful in the assessment phase of SHM. In this paper, we present a dual purpose sparsity-based imaging scheme which, in addition to accurately localizing defects, properly classifies the defects present simultaneously. The proposed approach takes advantage of the bias exhibited by certain types of defects toward a specific Lamb wave mode. For example, some defects strongly interact with the anti-symmetric modes, while others strongly interact with the symmetric modes. We build model based dictionaries for the fundamental symmetric and anti-symmetric wave modes, which are then utilized in unison to properly localize and classify the defects present. Simulated data of surface and internal defects in a thin Aluminum plate are used to validate the proposed scheme.

  20. Paravaginal defect: anatomy, clinical findings, and imaging

    PubMed Central

    Arenholt, Louise T.S.; Pedersen, Bodil Ginnerup; Glavind, Karin; Glavind-Kristensen, Marianne; DeLancey, John O.L.

    2017-01-01

    Introduction and Hypothesis The paravaginal defect has been a topic of active discussion concerning 1) what it is; 2) how to diagnose it; 3) its role in anterior vaginal wall prolapse; and 4) if and how to repair it. The aim of this article is to review the existing literature on the paravaginal defect and to discuss its role in the anterior vaginal wall support system, with an emphasis on anatomy and imaging. Methods Articles related to paravaginal defects were identified through a PUBMED search ending July 1, 2015. Results The support of the anterior vaginal wall is a complex system involving the levator ani muscle, the arcus tendineus fascia pelvis (ATFP), the pubocervical fascia, and the uterosacral/cardinal ligaments. Studies conclude that physical examination is inconsistent in detecting paravaginal defects. Ultrasound (US) and magnetic resonance imaging (MRI) have been used to describe patterns in the appearance of the vagina and bladder when a paravaginal defect is suspected. Different terms have been used (e.g. “sagging of bladder base,” “loss of tenting”), which all represent changes in the support of the pelvic floor but which could be due to both paravaginal defects and levator ani defects. Conclusion Paravaginal support plays a role in the support of the anterior vaginal wall, but we still do not know the degree to which it contributes to the development of prolapse. Both MRI and US are useful in the diagnosis of paravaginal defects, but further studies are needed to evaluate their use. PMID:27640064

  1. Congenital defects of the pericardium.

    PubMed

    Drury, Nigel E; De Silva, Ravi J; Hall, Roger M O; Large, Stephen R

    2007-04-01

    Congenital defects of the pericardium are rare, but when they are reported they are frequently associated with other cardiac lesions. We describe a case of partial pericardial defect found incidentally at surgery for closure of an ostium primum atrial septal defect. Proposed mechanisms of pericardial defect development are discussed and we suggest that associations with congenital and acquired heart disease are mostly circumstantial.

  2. Birth Defects. Matrix No. 2.

    ERIC Educational Resources Information Center

    Brent, Robert L.

    This report discusses the magnitude of the problem of birth defects, outlines advances in the birth defects field in the past decade, and identifies those areas where research is needed for the prevention, treatment, and management of birth defects. The problem of birth defects has consumed a greater portion of our health care resources because of…

  3. Utility of dual source CT with ECG-triggered high-pitch spiral acquisition (Flash Spiral Cardio mode) to evaluate morphological features of ventricles in children with complex congenital heart defects.

    PubMed

    Nakagawa, Motoo; Ozawa, Yoshiyuki; Nomura, Norikazu; Inukai, Sachiko; Tsubokura, Satoshi; Sakurai, Keita; Shimohira, Masashi; Ogawa, Masaki; Shibamoto, Yuta

    2016-04-01

    We evaluated the ability of dual source CT (DSCT) with ECG-triggered high-pitch spiral acquisition (Flash Spiral Cardio mode) to depict the morphological features of ventricles in pediatric patients with congenital heart defects (CHD). Between July 2013 and April 2015, 78 pediatric patients with CHD (median age 4 months) were examined using DSCT with the Flash Spiral Cardio mode. The types of ventricular abnormalities were ventricular septal defect (VSD) in 42 (the malaligned type in 11, perimembranous type in 23, supracristal type in 2, atrioventricular type in 2, and muscular type in 4), single ventricle (SV) in 11, and congenital corrected transposition of the great arteries (ccTGA) in 4. We evaluated the accuracy of the diagnosis of the VSD type. In cases of SV and ccTGA, we assessed the detectability of the anatomical features of both ventricles for a diagnosis of ventricular situs. DSCT confirmed the diagnoses for all VSDs. The type of defect was precisely diagnosed for all patients. The anatomical features of both ventricles were also depicted and ventricular situs of SV and ccTGA was correctly diagnosed. The results suggest that DSCT has the ability to clearly depict the configuration of ventricles.

  4. Wire insulation defect detector

    NASA Technical Reports Server (NTRS)

    Greulich, Owen R. (Inventor)

    2004-01-01

    Wiring defects are located by detecting a reflected signal that is developed when an arc occurs through the defect to a nearby ground. The time between the generation of the signal and the return of the reflected signal provides an indication of the distance of the arc (and therefore the defect) from the signal source. To ensure arcing, a signal is repeated at gradually increasing voltages while the wire being tested and a nearby ground are immersed in a conductive medium. In order to ensure that the arcing occurs at an identifiable time, the signal whose reflection is to be detected is always made to reach the highest potential yet seen by the system.

  5. Calvarial defect reconstruction.

    PubMed

    Jimenez, D F; Barone, C M

    1994-04-01

    The history of skull trepanation is almost as old as that of humanity. For thousands of years it has been performed for the treatment of numerous medical maladies. The Andean Incas, early Asians and South Seas Islanders, are amongst the many people to perform calvarial trepanation. Hippocrates described techniques for the use of the trepan in early Greek times. With the production of a skull opening comes the challenge of developing methods for closing the defect. It is in reality, more challenging to repair the defect than to create it. Man, with his never ending ingenuity, has tried to develop many techniques. We will discuss some of them and present our method of choice for closure of skull defects.

  6. Scanning electron microscope automatic defect classification of process induced defects

    NASA Astrophysics Data System (ADS)

    Wolfe, Scott; McGarvey, Steve

    2017-03-01

    With the integration of high speed Scanning Electron Microscope (SEM) based Automated Defect Redetection (ADR) in both high volume semiconductor manufacturing and Research and Development (R and D), the need for reliable SEM Automated Defect Classification (ADC) has grown tremendously in the past few years. In many high volume manufacturing facilities and R and D operations, defect inspection is performed on EBeam (EB), Bright Field (BF) or Dark Field (DF) defect inspection equipment. A comma separated value (CSV) file is created by both the patterned and non-patterned defect inspection tools. The defect inspection result file contains a list of the inspection anomalies detected during the inspection tools' examination of each structure, or the examination of an entire wafers surface for non-patterned applications. This file is imported into the Defect Review Scanning Electron Microscope (DRSEM). Following the defect inspection result file import, the DRSEM automatically moves the wafer to each defect coordinate and performs ADR. During ADR the DRSEM operates in a reference mode, capturing a SEM image at the exact position of the anomalies coordinates and capturing a SEM image of a reference location in the center of the wafer. A Defect reference image is created based on the Reference image minus the Defect image. The exact coordinates of the defect is calculated based on the calculated defect position and the anomalies stage coordinate calculated when the high magnification SEM defect image is captured. The captured SEM image is processed through either DRSEM ADC binning, exporting to a Yield Analysis System (YAS), or a combination of both. Process Engineers, Yield Analysis Engineers or Failure Analysis Engineers will manually review the captured images to insure that either the YAS defect binning is accurately classifying the defects or that the DRSEM defect binning is accurately classifying the defects. This paper is an exploration of the feasibility of the

  7. Supersymmetric k-defects

    DOE PAGES

    Koehn, Michael; Trodden, Mark

    2016-03-03

    In supersymmetric theories, topological defects can have nontrivial behaviors determined purely by whether or not supersymmetry is restored in the defect core. A well-known example of this is that some supersymmetric cosmic strings are automatically superconducting, leading to important cosmological effects and constraints. We investigate the impact of nontrivial kinetic interactions, present in a number of particle physics models of interest in cosmology, on the relationship between supersymmetry and supercurrents on strings. Furthermore, we find that in some cases it is possible for superconductivity to be disrupted by the extra interactions.

  8. First principles study of intrinsic defects in hexagonal tungsten carbide

    NASA Astrophysics Data System (ADS)

    Kong, Xiang-Shan; You, Yu-Wei; Xia, J. H.; Liu, C. S.; Fang, Q. F.; Luo, G.-N.; Huang, Qun-Ying

    2010-11-01

    The characteristics of intrinsic defects are important for the understanding of self-diffusion processes, mechanical strength, brittleness, and plasticity of tungsten carbide, which are present in the divertor of fusion reactors. Here, we use first-principles calculations to investigate the stability of point defects and their complexes in tungsten carbide. Our results confirm that the defect formation energies of carbon are much lower than that of tungsten and reveal the carbon vacancy to be the dominant defect in tungsten carbide. The C sbnd C dimer configuration along the dense a direction is the most stable configuration of carbon interstitial defect. The results of carbon defect diffusion show that the carbon vacancy stay for a wide range of temperature because of extremely high diffusion barriers, while carbon interstitial migration is activated at lower temperatures for its considerably lower activation energy. Both of them prefer to diffusion in carbon basal plane.

  9. Quantum computing with defects.

    PubMed

    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.

  10. Defect formation energy in pyrochlore: the effect of crystal size

    NASA Astrophysics Data System (ADS)

    Wang, Jianwei; Ewing, Rodney C.; Becker, Udo

    2014-09-01

    Defect formation energies of point defects of two pyrochlores Gd2Ti2O7 and Gd2Zr2O7 as a function of crystal size were calculated. Density functional theory with plane-wave basis sets and the projector-augmented wave method were used in the calculations. The results show that the defect formation energies of the two pyrochlores diverge as the size decreases to the nanometer range. For Gd2Ti2O7 pyrochlore, the defect formation energy is higher at nanometers with respect to that of the bulk, while it is lower for Gd2Zr2O7. The lowest defect formation energy for Gd2Zr2O7 is found at 15-20 Å. The different behaviors of the defect formation energies as a function of crystal size are caused by different structural adjustments around the defects as the size decreases. For both pyrochlore compositions at large sizes, the defect structures are similar to those of the bulk. As the size decreases, for Gd2Ti2O7, additional structure distortions appear at the surfaces, which cause the defect formation energy to increase. For Gd2Zr2O7, additional oxygen Frenkel pair defects are introduced, which reduce the defect formation energy. As the size further decreases, increased structure distortions occur at the surfaces, which cause the defect formation energy to increase. Based on a hypothesis that correlates the energetics of defect formation and radiation response for complex oxides, the calculated results suggest that at nanometer range Gd2Ti2O7 pyrochlore is expected to have a lower radiation tolerance, and those of Gd2Zr2O7 pyrochlore to have a higher radiation tolerance. The highest radiation tolerance for Gd2Zr2O7 pyrochlore is expected to be found at ˜2 nanometers.

  11. Congenital heart defect - corrective surgery

    MedlinePlus

    ... repair; Tetralogy of Fallot repair; Coarctation of the aorta repair; Atrial septal defect repair; Ventricular septal defect ... has a blood vessel that runs between the aorta (the main artery to the body) and the ...

  12. Adults with Congenital Heart Defects

    MedlinePlus

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Web Booklet: Adults With Congenital Heart Defects Updated:Aug ... topic from the list below to learn more. Web Booklet: Adults With Congenital Heart Defects Introduction Introduction: ...

  13. Congenital Heart Defects (For Parents)

    MedlinePlus

    ... or loses consciousness, call 911 . More treatments than ever are available for congenital heart defects, and most defects are treated successfully. Children with heart problems are best cared for by a team of specialists, which ...

  14. Facts about Ventricular Septal Defect

    MedlinePlus

    ... Living With Heart Defects Data & Statistics Tracking & Research Articles & Key Findings Free Materials Multimedia and Tools Links to Other Websites Information For… Media Policy Makers Facts about Ventricular Septal Defect Language: ...

  15. Facts about Atrial Septal Defect

    MedlinePlus

    ... Living With Heart Defects Data & Statistics Tracking & Research Articles & Key Findings Free Materials Multimedia and Tools Links to Other Websites Information For… Media Policy Makers Facts about Atrial Septal Defect Language: ...

  16. Facts about Congenital Heart Defects

    MedlinePlus

    ... Living With Heart Defects Data & Statistics Tracking & Research Articles & Key Findings Free Materials Multimedia and Tools Links to Other Websites Information For… Media Policy Makers Basics about Congenital Heart Defects Language: ...

  17. Defects in Quantum Computers

    DOE PAGES

    Gardas, Bartłomiej; Dziarmaga, Jacek; Zurek, Wojciech H.; ...

    2018-03-14

    The shift of interest from general purpose quantum computers to adiabatic quantum computing or quantum annealing calls for a broadly applicable and easy to implement test to assess how quantum or adiabatic is a specific hardware. Here we propose such a test based on an exactly solvable many body system–the quantum Ising chain in transverse field–and implement it on the D-Wave machine. An ideal adiabatic quench of the quantum Ising chain should lead to an ordered broken symmetry ground state with all spins aligned in the same direction. An actual quench can be imperfect due to decoherence, noise, flaws inmore » the implemented Hamiltonian, or simply too fast to be adiabatic. Imperfections result in topological defects: Spins change orientation, kinks punctuating ordered sections of the chain. Therefore, the number of such defects quantifies the extent by which the quantum computer misses the ground state, and is imperfect.« less

  18. Neural Tube Defects

    PubMed Central

    Greene, Nicholas D.E.; Copp, Andrew J.

    2015-01-01

    Neural tube defects (NTDs), including spina bifida and anencephaly, are severe birth defects of the central nervous system that originate during embryonic development when the neural tube fails to close completely. Human NTDs are multifactorial, with contributions from both genetic and environmental factors. The genetic basis is not yet well understood, but several nongenetic risk factors have been identified as have possibilities for prevention by maternal folic acid supplementation. Mechanisms underlying neural tube closure and NTDs may be informed by experimental models, which have revealed numerous genes whose abnormal function causes NTDs and have provided details of critical cellular and morphological events whose regulation is essential for closure. Such models also provide an opportunity to investigate potential risk factors and to develop novel preventive therapies. PMID:25032496

  19. Defects in Quantum Computers

    SciTech Connect

    Gardas, Bartłomiej; Dziarmaga, Jacek; Zurek, Wojciech H.

    The shift of interest from general purpose quantum computers to adiabatic quantum computing or quantum annealing calls for a broadly applicable and easy to implement test to assess how quantum or adiabatic is a specific hardware. Here we propose such a test based on an exactly solvable many body system–the quantum Ising chain in transverse field–and implement it on the D-Wave machine. An ideal adiabatic quench of the quantum Ising chain should lead to an ordered broken symmetry ground state with all spins aligned in the same direction. An actual quench can be imperfect due to decoherence, noise, flaws inmore » the implemented Hamiltonian, or simply too fast to be adiabatic. Imperfections result in topological defects: Spins change orientation, kinks punctuating ordered sections of the chain. Therefore, the number of such defects quantifies the extent by which the quantum computer misses the ground state, and is imperfect.« less

  20. Defect Genome of Cubic Perovskites for Fuel Cell Applications

    SciTech Connect

    Balachandran, Janakiraman; Lin, Lianshan; Anchell, Jonathan S.

    Heterogeneities such as point defects, inherent to material systems, can profoundly influence material functionalities critical for numerous energy applications. This influence in principle can be identified and quantified through development of large defect data sets which we call the defect genome, employing high-throughput ab initio calculations. However, high-throughput screening of material models with point defects dramatically increases the computational complexity and chemical search space, creating major impediments toward developing a defect genome. In this paper, we overcome these impediments by employing computationally tractable ab initio models driven by highly scalable workflows, to study formation and interaction of various point defectsmore » (e.g., O vacancies, H interstitials, and Y substitutional dopant), in over 80 cubic perovskites, for potential proton-conducting ceramic fuel cell (PCFC) applications. The resulting defect data sets identify several promising perovskite compounds that can exhibit high proton conductivity. Furthermore, the data sets also enable us to identify and explain, insightful and novel correlations among defect energies, material identities, and defect-induced local structural distortions. Finally, such defect data sets and resultant correlations are necessary to build statistical machine learning models, which are required to accelerate discovery of new materials.« less

  1. Defect Genome of Cubic Perovskites for Fuel Cell Applications

    DOE PAGES

    Balachandran, Janakiraman; Lin, Lianshan; Anchell, Jonathan S.; ...

    2017-10-10

    Heterogeneities such as point defects, inherent to material systems, can profoundly influence material functionalities critical for numerous energy applications. This influence in principle can be identified and quantified through development of large defect data sets which we call the defect genome, employing high-throughput ab initio calculations. However, high-throughput screening of material models with point defects dramatically increases the computational complexity and chemical search space, creating major impediments toward developing a defect genome. In this paper, we overcome these impediments by employing computationally tractable ab initio models driven by highly scalable workflows, to study formation and interaction of various point defectsmore » (e.g., O vacancies, H interstitials, and Y substitutional dopant), in over 80 cubic perovskites, for potential proton-conducting ceramic fuel cell (PCFC) applications. The resulting defect data sets identify several promising perovskite compounds that can exhibit high proton conductivity. Furthermore, the data sets also enable us to identify and explain, insightful and novel correlations among defect energies, material identities, and defect-induced local structural distortions. Finally, such defect data sets and resultant correlations are necessary to build statistical machine learning models, which are required to accelerate discovery of new materials.« less

  2. Study of lattice defect vibration

    NASA Technical Reports Server (NTRS)

    Elliott, R. J.

    1969-01-01

    Report on the vibrations of defects in crystals relates how defects, well localized in a crystal but interacting strongly with the other atoms, change the properties of a perfect crystal. The methods used to solve defect problems relate the properties of an imperfect lattice to the properties of a perfect lattice.

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

    NASA Astrophysics Data System (ADS)

    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.

  4. Surface defects and chiral algebras

    NASA Astrophysics Data System (ADS)

    Córdova, Clay; Gaiotto, Davide; Shao, Shu-Heng

    2017-05-01

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

  5. Lipoic acid biosynthesis defects.

    PubMed

    Mayr, Johannes A; Feichtinger, René G; Tort, Frederic; Ribes, Antonia; Sperl, Wolfgang

    2014-07-01

    Lipoate is a covalently bound cofactor essential for five redox reactions in humans: in four 2-oxoacid dehydrogenases and the glycine cleavage system (GCS). Two enzymes are from the energy metabolism, α-ketoglutarate dehydrogenase and pyruvate dehydrogenase; and three are from the amino acid metabolism, branched-chain ketoacid dehydrogenase, 2-oxoadipate dehydrogenase, and the GCS. All these enzymes consist of multiple subunits and share a similar architecture. Lipoate synthesis in mitochondria involves mitochondrial fatty acid synthesis up to octanoyl-acyl-carrier protein; and three lipoate-specific steps, including octanoic acid transfer to glycine cleavage H protein by lipoyl(octanoyl) transferase 2 (putative) (LIPT2), lipoate synthesis by lipoic acid synthetase (LIAS), and lipoate transfer by lipoyltransferase 1 (LIPT1), which is necessary to lipoylate the E2 subunits of the 2-oxoacid dehydrogenases. The reduced form dihydrolipoate is reactivated by dihydrolipoyl dehydrogenase (DLD). Mutations in LIAS have been identified that result in a variant form of nonketotic hyperglycinemia with early-onset convulsions combined with a defect in mitochondrial energy metabolism with encephalopathy and cardiomyopathy. LIPT1 deficiency spares the GCS, and resulted in a combined 2-oxoacid dehydrogenase deficiency and early death in one patient and in a less severely affected individual with a Leigh-like phenotype. As LIAS is an iron-sulphur-cluster-dependent enzyme, a number of recently identified defects in mitochondrial iron-sulphur cluster synthesis, including NFU1, BOLA3, IBA57, GLRX5 presented with deficiency of LIAS and a LIAS-like phenotype. As in DLD deficiency, a broader clinical spectrum can be anticipated for lipoate synthesis defects depending on which of the affected enzymes is most rate limiting.

  6. Maxillectomy defects: a suggested classification scheme.

    PubMed

    Akinmoladun, V I; Dosumu, O O; Olusanya, A A; Ikusika, O F

    2013-06-01

    The term "maxillectomy" has been used to describe a variety of surgical procedures for a spectrum of diseases involving a diverse anatomical site. Hence, classifications of maxillectomy defects have often made communication difficult. This article highlights this problem, emphasises the need for a uniform system of classification and suggests a classification system which is simple and comprehensive. Articles related to this subject, especially those with specified classifications of maxillary surgical defects were sourced from the internet through Google, Scopus and PubMed using the search terms maxillectomy defects classification. A manual search through available literature was also done. The review of the materials revealed many classifications and modifications of classifications from the descriptive, reconstructive and prosthodontic perspectives. No globally acceptable classification exists among practitioners involved in the management of diseases in the mid-facial region. There were over 14 classifications of maxillary defects found in the English literature. Attempts made to address the inadequacies of previous classifications have tended to result in cumbersome and relatively complex classifications. A single classification that is based on both surgical and prosthetic considerations is most desirable and is hereby proposed.

  7. Impact of isovalent doping on radiation defects in silicon

    NASA Astrophysics Data System (ADS)

    Londos, C. A.; Sgourou, E. N.; Timerkaeva, D.; Chroneos, A.; Pochet, P.; Emtsev, V. V.

    2013-09-01

    Isovalent doping is an important process for the control of point defects in Si. Here, by means of infrared spectroscopy, we investigated the properties of the two main radiation-induced defects in Czochralski-Si (Cz-Si) the oxygen-vacancy (VO) and the carbon-oxygen (CiOi) centres. In particular, we investigated the effect of isovalent doping on the production, the thermal evolution, and the thermal stability of the VO and the CiOi defects. Additionally, we studied the reactions that participate upon annealing and the defects formed as a result of these reactions. Upon annealing VO is converted to VO2 defect although part of the CiOi is converted to CsO2i complexes. Thus, we studied the conversion ratios [VO2]/[VO] and [CsO2i]/[CiOi] with respect to the isovalent dopant. Additionally, the role of carbon in the above processes was discussed. A delay between the temperature characterizing the onset of the VO decay and the temperature characterizing the VO2 growth as well the further growth of VO2 after the complete disappearance of VO indicate that the VO to VO2 conversion is a complex phenomenon with many reaction processes involved. Differences exhibited between the effects of the various dopants on the properties of the two defects were highlighted. The results are discussed in view of density functional theory calculations involving the interaction of isovalent dopants with intrinsic defects, the oxygen and carbon impurities in Si.

  8. First-Principles Study of Defects in GaN

    DTIC Science & Technology

    2009-07-29

    This means both Mg and Be are not suitable p-type dopants in AlN. c) We have calculated the Ga Frenkel pairs (interstitial Ga and gallium vacancy... gallium vacancy complexes) in GaN. We studied both the stability of the pair at different separations and the barriers for the pair to form/disintegrate...high in energy than vacancy defects, especially for covalent materials. However, in ionic materials the charged interstitial defects can have low

  9. Liability for Personal Injury Caused by Defective Medical Computer Programs

    PubMed Central

    Brannigan, Vincent M.

    1980-01-01

    Defective medical computer programs can cause personal injury. Financial responsibility for the injury under tort law will turn on several factors: whether the program is a product or a service, what types of defect exist in the product, and who produced the program. The factors involved in making these decisions are complex, but knowledge of the relevant issues can assist computer personnel in avoiding liability.

  10. Studies of Point Defects and Defect Interactions in Metals Using Perturbed Gamma Gamma Angular Correlations

    NASA Astrophysics Data System (ADS)

    Shropshire, Steven Leslie

    Point defects in plastically deformed Au, Pt, and Ni were studied with atomic-scale sensitivity using the perturbed gamma-gamma angular correlations (PAC) technique by monitoring formation and transformation of complexes of vacancy defects with very dilute ^{111}In/ ^{111}Cd solute probes. Three topics were investigated: (1) Production of vacancy defects during plastic deformation of Au was investigated to differentiate models of defect production. Concentrations of mono-, di-, and tri-vacancy species were measured in Au, and the ratio of mono- to di-vacancies was found to be independent of the amount of deformation. Results indicate that point defects are produced in correlated lattice locations, such as in "strings", as a consequence of dislocation interactions and not at random locations. (2) Hydrogen interactions with vacancy-solute complexes were studied in Pt. From thermal detrapping experiments, binding of hydrogen in complexes with mono-, di- and tri-vacancies was determined using a model for hydrogen diffusing in a medium with traps, with enthalpies all measured in the narrow range 0.23-0.28 eV, proving that the binding is insensitive to the precise structure of small vacancy clusters. Nuclear relaxation of the probe in a trivacancy complex in Pt was studied as a function of temperature, from which an activation energy of 0.34 eV was measured. This value is inconsistent with relaxation caused by diffusion or trapping of hydrogen, but explainable by dynamical hopping of the PAC probe atom in a cage of vacancies. (3) By observing transformations between vacancy-solute complexes induced by annihilation reactions, it was demonstrated that interstitials are produced during plastic deformation. The evolution of concentrations of the different vacancy complexes under an interstitial flux was measured and analyzed using a kinetic-rate model, from which interstitial capture cross-sections for the different vacancy complexes and the relative quantities of

  11. The CiCs(SiI)n Defect in Silicon from a Density Functional Theory Perspective.

    PubMed

    Christopoulos, Stavros-Richard G; Sgourou, Efstratia N; Vovk, Ruslan V; Chroneos, Alexander; Londos, Charalampos A

    2018-04-16

    Carbon constitutes a significant defect in silicon (Si) as it can interact with intrinsic point defects and affect the operation of devices. In heavily irradiated Si containing carbon the initially produced carbon interstitial-carbon substitutional (C i C s ) defect can associate with self-interstitials (Si I 's) to form, in the course of irradiation, the C i C s (Si I ) defect and further form larger complexes namely, C i C s (Si I ) n defects, by the sequential trapping of self-interstitials defects. In the present study, we use density functional theory to clarify the structure and energetics of the C i C s (Si I ) n defects. We report that the lowest energy C i C s (Si I ) and C i C s (Si I )₂ defects are strongly bound with -2.77 and -5.30 eV, respectively.

  12. Investigation of defect modes in a defective photonic crystal with a semiconductor metamaterial defect

    NASA Astrophysics Data System (ADS)

    Wu, Meng-Ru; Wu, Chien-Jang; Chang, Shoou-Jinn

    2014-11-01

    In this work, we theoretically investigate the properties of defect modes in a defective photonic crystal containing a semiconductor metamaterial defect. We consider the structure, (LH)N/DP/(LH)N, where N and P are respectively the stack numbers, L is SiO2, H is InP, and defect layer D is a semiconductor metamaterial composed of Al-doped ZnO (AZO) and ZnO. It is found that, within the photonic band gap, the number of defect modes (transmission peaks) will decrease as the defect thickness increases, in sharp contrast to the case of using usual dielectric defect. The peak height and position can be changed by the variation in the thickness of defect layer. In the angle-dependent defect mode, its position is shown to be blue-shifted as the angle of incidence increases for both TE and TM waves. The analysis of defect mode provides useful information for the design of tunable transmission filter in semiconductor optoelectronics.

  13. Topological defects in extended inflation

    NASA Technical Reports Server (NTRS)

    Copeland, Edmund J.; Kolb, Edward W.; Liddle, Andrew R.

    1990-01-01

    The production of topological defects, especially cosmic strings, in extended inflation models was considered. 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.

  14. Birth defects: Risk factors and consequences

    PubMed Central

    Oliveira, Camila Ive Ferreira; Fett-Conte, Agnes Cristina

    2013-01-01

    Birth defects (BDs) or congenital anomalies include all structural and functional alterations in embryonic or fetal development resulting from genetic, environmental or unknown causes, which result in physical and/or mental impairment. BDs occur in about 3% of newborn babies and in most cases of pregnancy loss. BDs are a very complex and heterogeneous group of single or multiple changes that, in most cases, are of unknown etiology. Among the risk factors are advanced maternal and paternal ages, parental consanguinity, teratogenic agents such as infectious agents and drugs, and poor nutrition, in particular folic acid deficiency. One of the consequences of these defects is the high death rate within the first year of life. Information on BDs is becoming increasingly more important throughout the world so that preventive measures can be taken. Knowledge of BDs enables the development of therapeutic and preventive strategies besides adequate genetic counseling. PMID:27625844

  15. Density functional theory study of defects in unalloyed δ-Pu

    DOE PAGES

    Hernandez, S. C.; Freibert, F. J.; Wills, J. M.

    2017-03-19

    Using density functional theory, we explore in this paper various classical point and complex defects within the face-centered cubic unalloyed δ-plutonium matrix that are potentially induced from self-irradiation. For plutonium only defects, the most energetically stable defect is a distorted split-interstitial. Gallium, the δ-phase stabilizer, is thermodynamically stable as a substitutional defect, but becomes unstable when participating in a complex defect configuration. Finally, complex uranium defects may thermodynamically exist as uranium substitutional with neighboring plutonium interstitial and stabilization of uranium within the lattice is shown via partial density of states and charge density difference plots to be 5f hybridization betweenmore » uranium and plutonium.« less

  16. Density functional theory study of defects in unalloyed δ-Pu

    SciTech Connect

    Hernandez, S. C.; Freibert, F. J.; Wills, J. M.

    Using density functional theory, we explore in this paper various classical point and complex defects within the face-centered cubic unalloyed δ-plutonium matrix that are potentially induced from self-irradiation. For plutonium only defects, the most energetically stable defect is a distorted split-interstitial. Gallium, the δ-phase stabilizer, is thermodynamically stable as a substitutional defect, but becomes unstable when participating in a complex defect configuration. Finally, complex uranium defects may thermodynamically exist as uranium substitutional with neighboring plutonium interstitial and stabilization of uranium within the lattice is shown via partial density of states and charge density difference plots to be 5f hybridization betweenmore » uranium and plutonium.« less

  17. Stable Defects in Semiconductor Nanowires.

    PubMed

    Sanchez, A M; Gott, J A; Fonseka, H A; Zhang, Y; Liu, H; Beanland, R

    2018-05-09

    Semiconductor nanowires are commonly described as being defect-free due to their ability to expel mobile defects with long-range strain fields. Here, we describe previously undiscovered topologically protected line defects with null Burgers vector that, unlike dislocations, are stable in nanoscale crystals. We analyze the defects present in semiconductor nanowires in regions of imperfect crystal growth, i.e., at the nanowire tip formed during consumption of the droplet in self-catalyzed vapor-liquid-solid growth and subsequent vapor-solid shell growth. We use a form of the Burgers circuit method that can be applied to multiply twinned material without difficulty. Our observations show that the nanowire microstructure is very different from bulk material, with line defects either (a) trapped by locks or other defects, (b) arranged as dipoles or groups with a zero total Burgers vector, or (c) have a zero Burgers vector. We find two new line defects with a null Burgers vector, formed from the combination of partial dislocations in twinned material. The most common defect is the three-monolayer high twin facet with a zero Burgers vector. Studies of individual nanowires using cathodoluminescence show that optical emission is quenched in defective regions, showing that they act as strong nonradiative recombination centers.

  18. Fetal anterior abdominal wall defects: prenatal imaging by magnetic resonance imaging.

    PubMed

    Victoria, Teresa; Andronikou, Savvas; Bowen, Diana; Laje, Pablo; Weiss, Dana A; Johnson, Ann M; Peranteau, William H; Canning, Douglas A; Adzick, N Scott

    2018-04-01

    Abdominal wall defects range from the mild umbilical cord hernia to the highly complex limb-body wall syndrome. The most common defects are gastroschisis and omphalocele, and the rarer ones include the exstrophy complex, pentalogy of Cantrell and limb-body wall syndrome. Although all have a common feature of viscera herniation through a defect in the anterior body wall, their imaging features and, more important, postnatal management, differ widely. Correct diagnosis of each entity is imperative in order to achieve appropriate and accurate prenatal counseling and postnatal management. In this paper, we discuss fetal abdominal wall defects and present diagnostic pearls to aid with diagnosis.

  19. Lumber defect detection by ultrasonics

    Treesearch

    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.

  20. Production and evolution of A-centers in n-type Si1-xGex

    NASA Astrophysics Data System (ADS)

    Sgourou, E. N.; Andrianakis, A.; Londos, C. A.; Chroneos, A.

    2013-03-01

    The vacancy-oxygen pair (VO or A-center) in n-type Si1-xGex crystals (x = 0, 0.025, 0.055) has been studied using infrared (IR) spectroscopy. It is determined that the VO production is suppressed in the case of n-type Si1-xGex as compared to Si. It is observed that the annealing temperature of the VO defect in Si1-xGex is substantially lower as compared to Si. The decay of the VO (830 cm-1) band, in the course of 20 min isochronal anneals, shows two stages: The onset of the first stage is at ˜180 °C and the decrease of the VO signal is accompanied in the spectra by the increase of the intensity of two bands at ˜834 and 839 cm-1. These bands appear in the spectra immediately after irradiation and were previously correlated with (VO-Ge) structures. The onset of the second stage occurs at ˜250 °C were the 830 cm-1 band of VO and the above two bands of (VO-Ge) decrease together in the spectra accompanied by the simultaneous growth of the 885 cm-1 band of the VO2 defect. Interestingly, the percentage of the VO pairs that are converted to VO2 defects is larger in the Si1-xGex samples with intermediate Ge content (x = 0.025) as compared with Si (x = 0) and with the high Ge content samples (x = 0.055). The results are discussed in view of the association of VO pairs with Ge.

  1. Surface defects and chiral algebras

    DOE PAGES

    Córdova, Clay; Gaiotto, Davide; Shao, Shu-Heng

    2017-05-26

    Here, 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 Drinfield-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. We find perfect agreement with the predicted characters, in eachmore » case.« less

  2. Holographic Chern-Simons defects

    DOE PAGES

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

    2016-06-28

    Here, 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 themore » defects as well as the temperature are varied. We also discuss some implications for the Fractional Quantum Hall Effect and for 2-dimensional QCD.« less

  3. Surface defects and chiral algebras

    SciTech Connect

    Córdova, Clay; Gaiotto, Davide; Shao, Shu-Heng

    Here, 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 Drinfield-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. We find perfect agreement with the predicted characters, in eachmore » case.« less

  4. Toward Intelligent Software Defect Detection

    NASA Technical Reports Server (NTRS)

    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.

  5. Defect phase diagram for doping of Ga2O3

    NASA Astrophysics Data System (ADS)

    Lany, Stephan

    2018-04-01

    For the case of n-type doping of β-Ga2O3 by group 14 dopants (C, Si, Ge, Sn), a defect phase diagram is constructed from defect equilibria calculated over a range of temperatures (T), O partial pressures (pO2), and dopant concentrations. The underlying defect levels and formation energies are determined from first-principles supercell calculations with GW bandgap corrections. Only Si is found to be a truly shallow donor, C is a deep DX-like (lattice relaxed donor) center, and Ge and Sn have defect levels close to the conduction band minimum. The thermodynamic modeling includes the effect of association of dopant-defect pairs and complexes, which causes the net doping to decline when exceeding a certain optimal dopant concentration. The optimal doping levels are surprisingly low, between about 0.01% and 1% of cation substitution, depending on the (T, pO2) conditions. Considering further the stability constraints due to sublimation of molecular Ga2O, specific predictions of optimized pO2 and Si dopant concentrations are given. The incomplete passivation of dopant-defect complexes in β-Ga2O3 suggests a design rule for metastable doping above the solubility limit.

  6. Defect phase diagram for doping of Ga 2O 3

    DOE PAGES

    Lany, Stephan

    2018-04-01

    For the case of n-type doping of β-Ga 2O 3 by group 14 dopants (C, Si, Ge, Sn), a defect phase diagram is constructed from defect equilibria calculated over a range of temperatures (T), O partial pressures (pO 2), and dopant concentrations. The underlying defect levels and formation energies are determined from first-principles supercell calculations with GW bandgap corrections. Only Si is found to be a truly shallow donor, C is a deep DX-like (lattice relaxed donor) center, and Ge and Sn have defect levels close to the conduction band minimum. The thermodynamic modeling includes the effect of association ofmore » dopant-defect pairs and complexes, which causes the net doping to decline when exceeding a certain optimal dopant concentration. The optimal doping levels are surprisingly low, between about 0.01% and 1% of cation substitution, depending on the (T, pO 2) conditions. Considering further the stability constraints due to sublimation of molecular Ga 2O, specific predictions of optimized pO 2 and Si dopant concentrations are given. To conclude, the incomplete passivation of dopant-defect complexes in β-Ga 2O 3 suggests a design rule for metastable doping above the solubility limit.« less

  7. Defect phase diagram for doping of Ga 2O 3

    SciTech Connect

    Lany, Stephan

    For the case of n-type doping of β-Ga 2O 3 by group 14 dopants (C, Si, Ge, Sn), a defect phase diagram is constructed from defect equilibria calculated over a range of temperatures (T), O partial pressures (pO 2), and dopant concentrations. The underlying defect levels and formation energies are determined from first-principles supercell calculations with GW bandgap corrections. Only Si is found to be a truly shallow donor, C is a deep DX-like (lattice relaxed donor) center, and Ge and Sn have defect levels close to the conduction band minimum. The thermodynamic modeling includes the effect of association ofmore » dopant-defect pairs and complexes, which causes the net doping to decline when exceeding a certain optimal dopant concentration. The optimal doping levels are surprisingly low, between about 0.01% and 1% of cation substitution, depending on the (T, pO 2) conditions. Considering further the stability constraints due to sublimation of molecular Ga 2O, specific predictions of optimized pO 2 and Si dopant concentrations are given. To conclude, the incomplete passivation of dopant-defect complexes in β-Ga 2O 3 suggests a design rule for metastable doping above the solubility limit.« less

  8. Design and analysis of forward and reverse models for predicting defect accumulation, defect energetics, and irradiation conditions

    DOE PAGES

    Stewart, James A.; Kohnert, Aaron A.; Capolungo, Laurent; ...

    2018-03-06

    The complexity of radiation effects in a material’s microstructure makes developing predictive models a difficult task. In principle, a complete list of all possible reactions between defect species being considered can be used to elucidate damage evolution mechanisms and its associated impact on microstructure evolution. However, a central limitation is that many models use a limited and incomplete catalog of defect energetics and associated reactions. Even for a given model, estimating its input parameters remains a challenge, especially for complex material systems. Here, we present a computational analysis to identify the extent to which defect accumulation, energetics, and irradiation conditionsmore » can be determined via forward and reverse regression models constructed and trained from large data sets produced by cluster dynamics simulations. A global sensitivity analysis, via Sobol’ indices, concisely characterizes parameter sensitivity and demonstrates how this can be connected to variability in defect evolution. Based on this analysis and depending on the definition of what constitutes the input and output spaces, forward and reverse regression models are constructed and allow for the direct calculation of defect accumulation, defect energetics, and irradiation conditions. Here, this computational analysis, exercised on a simplified cluster dynamics model, demonstrates the ability to design predictive surrogate and reduced-order models, and provides guidelines for improving model predictions within the context of forward and reverse engineering of mathematical models for radiation effects in a materials’ microstructure.« less

  9. Design and analysis of forward and reverse models for predicting defect accumulation, defect energetics, and irradiation conditions

    SciTech Connect

    Stewart, James A.; Kohnert, Aaron A.; Capolungo, Laurent

    The complexity of radiation effects in a material’s microstructure makes developing predictive models a difficult task. In principle, a complete list of all possible reactions between defect species being considered can be used to elucidate damage evolution mechanisms and its associated impact on microstructure evolution. However, a central limitation is that many models use a limited and incomplete catalog of defect energetics and associated reactions. Even for a given model, estimating its input parameters remains a challenge, especially for complex material systems. Here, we present a computational analysis to identify the extent to which defect accumulation, energetics, and irradiation conditionsmore » can be determined via forward and reverse regression models constructed and trained from large data sets produced by cluster dynamics simulations. A global sensitivity analysis, via Sobol’ indices, concisely characterizes parameter sensitivity and demonstrates how this can be connected to variability in defect evolution. Based on this analysis and depending on the definition of what constitutes the input and output spaces, forward and reverse regression models are constructed and allow for the direct calculation of defect accumulation, defect energetics, and irradiation conditions. Here, this computational analysis, exercised on a simplified cluster dynamics model, demonstrates the ability to design predictive surrogate and reduced-order models, and provides guidelines for improving model predictions within the context of forward and reverse engineering of mathematical models for radiation effects in a materials’ microstructure.« less

  10. Frequent phosphodiesterase 11A gene (PDE11A) defects in patients with Carney complex (CNC) caused by PRKAR1A mutations: PDE11A may contribute to adrenal and testicular tumors in CNC as a modifier of the phenotype.

    PubMed

    Libé, Rossella; Horvath, Anelia; Vezzosi, Delphine; Fratticci, Amato; Coste, Joel; Perlemoine, Karine; Ragazzon, Bruno; Guillaud-Bataille, Marine; Groussin, Lionel; Clauser, Eric; Raffin-Sanson, Marie-Laure; Siegel, Jennifer; Moran, Jason; Drori-Herishanu, Limor; Faucz, Fabio Rueda; Lodish, Maya; Nesterova, Maria; Bertagna, Xavier; Bertherat, Jerome; Stratakis, Constantine A

    2011-01-01

    Carney complex (CNC) is an autosomal dominant multiple neoplasia, caused mostly by inactivating mutations of the regulatory subunit 1A of the protein kinase A (PRKAR1A). Primary pigmented nodular adrenocortical disease (PPNAD) is the most frequent endocrine manifestation of CNC with a great inter-individual variability. Germline, protein-truncating mutations of phosphodiesterase type 11A (PDE11A) have been described to predispose to a variety of endocrine tumors, including adrenal and testicular tumors. Our objective was to investigate the role of PDE11A as a possible gene modifier of the phenotype in a series of 150 patients with CNC. A higher frequency of PDE11A variants in patients with CNC compared with healthy controls was found (25.3 vs. 6.8%, P < 0.0001). Among CNC patients, those with PPNAD were significantly more frequently carriers of PDE11A variants compared with patients without PPNAD (30.8 vs. 13%, P = 0.025). Furthermore, men with PPNAD were significantly more frequently carriers of PDE11A sequence variants (40.7%) than women with PPNAD (27.3%) (P < 0.001). A higher frequency of PDE11A sequence variants was also found in patients with large-cell calcifying Sertoli cell tumors (LCCSCT) compared with those without LCCSCT (50 vs. 10%, P = 0.0056). PDE11A variants were significantly associated with the copresence of PPNAD and LCCSCT in men: 81 vs. 20%, P < 0.004). The simultaneous inactivation of PRKAR1A and PDE11A by small inhibitory RNA led to an increase in cAMP-regulatory element-mediated transcriptional activity under basal conditions and after stimulation by forskolin. We demonstrate, in a large cohort of CNC patients, a high frequency of PDE11A variants, suggesting that PDE11A is a genetic modifying factor for the development of testicular and adrenal tumors in patients with germline PRKAR1A mutation.

  11. Serine biosynthesis and transport defects.

    PubMed

    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.

  12. Disclinations, dislocations, and continuous defects: A reappraisal

    NASA Astrophysics Data System (ADS)

    Kleman, M.; Friedel, J.

    2008-01-01

    Disclinations were first observed in mesomorphic phases. They were later found relevant to a number of ill-ordered condensed-matter media involving continuous symmetries or frustrated order. Disclinations also appear in polycrystals at the edges of grain boundaries; but they are of limited interest in solid single crystals, where they can move only by diffusion climb and, owing to their large elastic stresses, mostly appear in close pairs of opposite signs. The relaxation mechanisms associated with a disclination in its creation, motion, and change of shape involve an interplay with continuous or quantized dislocations and/or continuous disclinations. These are attached to the disclinations or are akin to Nye’s dislocation densities, which are particularly well suited for consideration here. The notion of an extended Volterra process is introduced, which takes these relaxation processes into account and covers different situations where this interplay takes place. These concepts are illustrated by a variety of applications in amorphous solids, mesomorphic phases, and frustrated media in their curved habit space. These often involve disclination networks with specific node conditions. The powerful topological theory of line defects considers only defects stable against any change of boundary conditions or relaxation processes compatible with the structure considered. It can be seen as a simplified case of the approach considered here, particularly suited for media of high plasticity or/and complex structures. It cannot analyze the dynamical properties of defects nor the elastic constants involved in their static properties; topological stability cannot guarantee energetic stability, and sometimes cannot distinguish finer details of the structure of defects.

  13. Safety assessment for In-service Pressure Bending Pipe Containing Incomplete Penetration Defects

    NASA Astrophysics Data System (ADS)

    Wang, M.; Tang, P.; Xia, J. F.; Ling, Z. W.; Cai, G. Y.

    2017-12-01

    Incomplete penetration defect is a common defect in the welded joint of pressure pipes. While the safety classification of pressure pipe containing incomplete penetration defects, according to periodical inspection regulations in present, is more conservative. For reducing the repair of incomplete penetration defect, a scientific and applicable safety assessment method for pressure pipe is needed. In this paper, the stress analysis model of the pipe system was established for the in-service pressure bending pipe containing incomplete penetration defects. The local finite element model was set up to analyze the stress distribution of defect location and the stress linearization. And then, the applicability of two assessment methods, simplified assessment and U factor assessment method, to the assessment of incomplete penetration defects located at pressure bending pipe were analyzed. The results can provide some technical supports for the safety assessment of complex pipelines in the future.

  14. Self healing of defected graphene

    SciTech Connect

    Chen, Jianhui; Shi, Tuwan; Cai, Tuocheng

    For electronics applications, defects in graphene are usually undesirable because of their ability to scatter charge carriers, thereby reduce the carrier mobility. It would be extremely useful if the damage can be repaired. In this work, we employ Raman spectroscopy, X-ray photoemission spectroscopy, transmission electron microscopy, and electrical measurements to study defects in graphene introduced by argon plasma bombardment. We have found that majority of these defects can be cured by a simple thermal annealing process. The self-healing is attributed to recombination of mobile carbon adatoms with vacancies. With increasing level of plasma induced damage, the self-healing becomes less effective.

  15. Defect dynamics in active nematics

    PubMed Central

    Giomi, Luca; Bowick, Mark J; Mishra, Prashant; Sknepnek, Rastko; Cristina Marchetti, M

    2014-01-01

    Topological defects are distinctive signatures of liquid crystals. They profoundly affect the viscoelastic behaviour of the fluid by constraining the orientational structure in a way that inevitably requires global changes not achievable with any set of local deformations. In active nematic liquid crystals, topological defects not only dictate the global structure of the director, but also act as local sources of motion, behaving as self-propelled particles. In this article, we present a detailed analytical and numerical study of the mechanics of topological defects in active nematic liquid crystals. PMID:25332389

  16. Effects of defects in composite structures

    NASA Technical Reports Server (NTRS)

    Sendeckyj, G. P.

    1983-01-01

    The effect of defects in composite structures is addressed. Defects in laminates such as wrinkles, foreign particles, scratches and breaks are discussed. Effects of plygap plywaviness and machining defects are also studied.

  17. Reproduction and Survival After Cardiac Defect Repair

    ClinicalTrials.gov

    2016-02-17

    Cardiovascular Diseases; Heart Diseases; Defect, Congenital Heart; Aortic Valve Stenosis; Transposition of Great Vessels; Ductus Arteriosus, Patent; Heart Septal Defects, Atrial; Heart Septal Defects, Ventricular; Down Syndrome; Tetralogy of Fallot; Pulmonic Stenosis; Coarctation of Aorta

  18. Care and Treatment for Congenital Heart Defects

    MedlinePlus

    ... Physical Activity Recommendations for Heart Health • Tools & Resources Web Booklets on Congenital Heart Defects These online publications ... to you or your child’s defect and concerns. Web Booklet: Adults With Congenital Heart Defects Web Booklet: ...

  19. Identification of Complex Carbon Nanotube Structures

    NASA Technical Reports Server (NTRS)

    Han, Jie; Saini, Subhash (Technical Monitor)

    1998-01-01

    A variety of complex carbon nanotube (CNT) structures have been observed experimentally. These include sharp bends, branches, tori, and helices. They are believed to be formed by using topological defects such as pentagons and heptagons to connect different CNT. The effects of type, number, and arrangement (separation and orientation) of defects on atomic structures and energetics of complex CNT are investigated using topology, quantum mechanics and molecular mechanics calculations. Energetically stable models are derived for identification of observed complex CNT structures.

  20. Vacancy Defects as Compensating Centers in Mg-Doped GaN

    NASA Astrophysics Data System (ADS)

    Hautakangas, S.; Oila, J.; Alatalo, M.; Saarinen, K.; Liszkay, L.; Seghier, D.; Gislason, H. P.

    2003-04-01

    We apply positron annihilation spectroscopy to identify VN-MgGa complexes as native defects in Mg-doped GaN. These defects dissociate in postgrowth annealings at 500 800 °C. We conclude that VN-MgGa complexes contribute to the electrical compensation of Mg as well as the activation of p-type conductivity in the annealing. The observation of VN-MgGa complexes confirms that vacancy defects in either the N or Ga sublattice are abundant in GaN at any position of the Fermi level during growth, as predicted previously by theoretical calculations.

  1. Birth Defects & Other Health Conditions

    MedlinePlus

    ... Congenital heart defects and CCHD Congenital syphilis Congenital Zika syndrome Coxsackie infection and your baby Cystic fibrosis ... families in our new awareness campaign video. GO Zika services near you Visit Zika Care Connect to ...

  2. Birth Defects Research and Tracking

    MedlinePlus

    ... least one month before getting pregnant and during early pregnancy lowers the risk of having a baby with ... 2017) Key Findings: Use of Pain Medicine During Early Pregnancy May Be Related To Birth Defects A study ...

  3. Low quantum defect laser performance

    NASA Astrophysics Data System (ADS)

    Bowman, Steven R.

    2017-01-01

    Low quantum defect lasers are possible using near-resonant optical pumping. This paper examines the laser material performance as the quantum defect of the laser is reduced. A steady-state model is developed, which incorporates the relevant physical processes in these materials and predicts extraction efficiency and waste heat generation. As the laser quantum defect is reduced below a few percent, the impact of fluorescence cooling must be included in the analysis. The special case of a net zero quantum defect laser is examined in detail. This condition, referred to as the radiation balance laser (RBL), is shown to provide two orders of magnitude lower heat generation at the cost of roughly 10% loss in extraction efficiency. Numerical examples are presented with the host materials Yb:YAG and Yb:Silica. The general conditions, which yield optimal laser efficiency, are derived and explored.

  4. Sequential detection of web defects

    DOEpatents

    Eichel, Paul H.; Sleefe, Gerard E.; Stalker, K. Terry; Yee, Amy A.

    2001-01-01

    A system for detecting defects on a moving web having a sequential series of identical frames uses an imaging device to form a real-time camera image of a frame and a comparitor to comparing elements of the camera image with corresponding elements of an image of an exemplar frame. The comparitor provides an acceptable indication if the pair of elements are determined to be statistically identical; and a defective indication if the pair of elements are determined to be statistically not identical. If the pair of elements is neither acceptable nor defective, the comparitor recursively compares the element of said exemplar frame with corresponding elements of other frames on said web until one of the acceptable or defective indications occur.

  5. DNA Repair Defects and Chromosomal Aberrations

    NASA Technical Reports Server (NTRS)

    Hada, Megumi; George, K. A.; Huff, J. L.; Pluth, J. M.; Cucinotta, F. A.

    2009-01-01

    Yields of chromosome aberrations were assessed in cells deficient in DNA doublestrand break (DSB) repair, after exposure to acute or to low-dose-rate (0.018 Gy/hr) gamma rays or acute high LET iron nuclei. We studied several cell lines including fibroblasts deficient in ATM (ataxia telangiectasia mutated; product of the gene that is mutated in ataxia telangiectasia patients) or NBS (nibrin; product of the gene mutated in the Nijmegen breakage syndrome), and gliomablastoma cells that are proficient or lacking in DNA-dependent protein kinase (DNA-PK) activity. Chromosomes were analyzed using the fluorescence in situ hybridization (FISH) chromosome painting method in cells at the first division post irradiation, and chromosome aberrations were identified as either simple exchanges (translocations and dicentrics) or complex exchanges (involving >2 breaks in 2 or more chromosomes). Gamma irradiation induced greater yields of both simple and complex exchanges in the DSB repair-defective cells than in the normal cells. The quadratic dose-response terms for both simple and complex chromosome exchanges were significantly higher for the ATM- and NBS-deficient lines than for normal fibroblasts. However, in the NBS cells the linear dose-response term was significantly higher only for simple exchanges. The large increases in the quadratic dose-response terms in these repair-defective cell lines points the importance of the functions of ATM and NBS in chromatin modifications to facilitate correct DSB repair and minimize the formation of aberrations. The differences found between ATM- and NBS-deficient cells at low doses suggest that important questions should with regard to applying observations of radiation sensitivity at high dose to low-dose exposures. For aberrations induced by iron nuclei, regression models preferred purely linear dose responses for simple exchanges and quadratic dose responses for complex exchanges. Relative biological effectiveness (RBE) factors of all of

  6. Reconstruction of periorbital soft tissue defects.

    PubMed

    Berli, Jens U; Merbs, Shannath L; Grant, Michael P

    2014-10-01

    Because of the complex anatomy and fine mechanics of the periorbital soft tissues, the reconstruction of this region can be particularly daunting. Through a structured assessment of the defect, based on subunit analysis and thorough understanding of the surgical layers, we believe to allow the reconstructive surgeon to develop an algorithmic approach to these complex problems. The sequela of a suboptimal reconstruction do not only result in an inferior aesthetic result, but also have the potential for long-term functional problems such as epiphora, dry eye, ptosis, eyelid retraction, and thus requiring secondary surgery. There is no better time to aim for a perfect reconstruction than at the time of the initial surgery. In this chapter, we hope to encourage the reader to strengthen and recapitulate these analytical skills and present the most commonly used and studied techniques to help achieve a reproducible functional and aesthetically appealing result. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  7. Mental Images and the Modification of Learning Defects.

    ERIC Educational Resources Information Center

    Patten, Bernard M.

    Because human memory and thought involve extremely complex processes, it is possible to employ unusual modalities and specific visual strategies for remembering and problem-solving to assist patients with memory defects. This three-part paper discusses some of the research in the field of human memory and describes practical applications of these…

  8. Topological defects from the multiverse

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

  9. Topological defects from the multiverse

    SciTech Connect

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

    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 bemore » 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.« less

  10. Topological defects from the multiverse

    SciTech Connect

    Zhang, Jun; Blanco-Pillado, Jose J.; IKERBASQUE, Basque Foundation for Science, 48013, Bilbao

    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 bemore » 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.« less

  11. Generation and characterization of point defects in SrTiO3 and Y3Al5O12

    NASA Astrophysics Data System (ADS)

    Selim, F. A.; Winarski, D.; Varney, C. R.; Tarun, M. C.; Ji, Jianfeng; McCluskey, M. D.

    Positron annihilation lifetime spectroscopy (PALS) was applied to characterize point defects in single crystals of Y3Al5O12 and SrTiO3 after populating different types of defects by relevant thermal treatments. In SrTiO3, PALS measurements identified Sr vacancy, Ti vacancy, vacancy complexes of Ti-O (vacancy) and hydrogen complex defects. In Y3Al5O12 single crystals the measurements showed the presence of Al-vacancy, (Al-O) vacancy and Al-vacancy passivated by hydrogen. These defects are shown to play the major role in defining the electronic and optical properties of these complex oxides.

  12. Swelling Mechanisms of UO2 Lattices with Defect Ingrowths

    PubMed Central

    Günay, Seçkin D.

    2015-01-01

    The swelling that occurs in uranium dioxide as a result of radiation-induced defect ingrowth is not fully understood. Experimental and theoretical groups have attempted to explain this phenomenon with various complex theories. In this study, experimental lattice expansion and lattice super saturation were accurately reproduced using a molecular dynamics simulation method. Based on their resemblance to experimental data, the simulation results presented here show that fission induces only oxygen Frenkel pairs while alpha particle irradiation results in both oxygen and uranium Frenkel pair defects. Moreover, in this work, defects are divided into two sub-groups, obstruction type defects and distortion type defects. It is shown that obstruction type Frenkel pairs are responsible for both fission- and alpha-particle-induced lattice swelling. Relative lattice expansion was found to vary linearly with the number of obstruction type uranium Frenkel defects. Additionally, at high concentrations, some of the obstruction type uranium Frenkel pairs formed diatomic and triatomic structures with oxygen ions in their octahedral cages, increasing the slope of the linear dependence. PMID:26244777

  13. Potential implications of the helical heart in congenital heart defects.

    PubMed

    Corno, Antonio F; Kocica, Mladen J

    2007-01-01

    The anatomic and functional observations made by Francisco Torrent-Guasp, in particular his discovery of the helical ventricular myocardial band (HVMB), have challenged what has been taught to cardiologists and cardiac surgeons over centuries. A literature debate is ongoing, with interdependent articles and comments from supporters and critics. Adequate understanding of heart structure and function is obviously indispensable for the decision-making process in congenital heart defects. The HVMB described by Torrent-Guasp and the potential impact on the understanding and treatment of congenital heart defects has been analyzed in the following settings: embryology, ventriculo-arterial discordance (transposition of great arteries), Ebstein's anomaly, pulmonary valve regurgitation after repair of tetralogy of Fallot, Ross operation, and other congenital heart defects. The common structural spiral feature is only one of the elements responsible for the functional interaction of right and left ventricles, and understanding the form/function relationship in congenital heart defects is more difficult than for acquired heart disease because of the variety and complexity of congenital heart defects. Individuals involved in the care of patients with congenital heart defects have to be stimulated to consider further investigations and alternative surgical strategies.

  14. A Center for Extraterrestrial Engineering and Construction (CETEC)

    NASA Technical Reports Server (NTRS)

    Leigh, Gerald G.

    1992-01-01

    A group of knowledgeable scientists and engineers in New Mexico has recognized the need for such a testing capability and has proposed a project to evelop an extraterrestrial surface simulation facility. A group of universities, national laboratories, and private industrial firms is proposing to establish a Center for Extraterrestrial Engineering and Construction (CETEC) and to develop large extraterrestrial surface simulation facilities in which this needed testing can be realistically performed. The CETEC is envisioned to be both a center of knowledge and data regarding engineering, construction, mining, and material process operations on extraterrestrial bodies and a set of extraterrestrial surface simulation facilities. The primary CETEC facility is proposed to be a large domed building made of steel reinforced concrete with more than one acre of test floor area covered with several feet of simulated lunar soil and dust. Various aspects of the project are presented in viewgraph form.

  15. On the validity of the amphoteric-defect model in gallium arsenide and a criterion for Fermi-level pinning by defects

    NASA Astrophysics Data System (ADS)

    Chen, C.-H.; Tan, T. Y.

    1995-10-01

    Using the theoretically calculated point-defect total-energy values of Baraff and Schlüter in GaAs, an amphoteric-defect model has been proposed by Walukiewicz to explain a large number of experimental results. The suggested amphoteric-defect system consists of two point-defect species capable of transforming into each other: the doubly negatively charged Ga vacancy V {Ga/2-} and the triply positively charged defect complex (ASGa+ V As)3+, with AsGa being the antisite defect of an As atom occupying a Ga site and V As being an As vacancy. When present in sufficiently high concentrations, the amphoteric defect system V {Ga/2-}/(AsGa+ V As)3+ is supposed to be able to pin the GaAs Fermi level at approximately the E v +0.6 eV level position, which requires that the net free energy of the V Ga/(AsGa+ V As) defect system to be minimum at the same Fermi-level position. We have carried out a quantitative study of the net energy of this defect system in accordance with the individual point-defect total-energy results of Baraff and Schlüter, and found that the minimum net defect-system-energy position is located at about the E v +1.2 eV level position instead of the needed E v +0.6 eV position. Therefore, the validity of the amphoteric-defect model is in doubt. We have proposed a simple criterion for determining the Fermi-level pinning position in the deeper part of the GaAs band gap due to two oppositely charged point-defect species, which should be useful in the future.

  16. Effective actions for bosonic topological defects

    NASA Technical Reports Server (NTRS)

    Gregory, Ruth

    1990-01-01

    A gauge field theory is considered which admits p-dimensional topological defects, expanding the equations of motion in powers of the defect thickness. In this way an effective action and effective equation of motion is derived for the defect in terms of the coordinates of the p-dimensional worldsurface defined by the history of the core of the defect.

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

    NASA Astrophysics Data System (ADS)

    Zubiaga, A.; Garcia, J. A.; Plazaola, F.; Zúñiga-Pérez, J.; Muñoz-Sanjosé, 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.

  18. Defect-mediated turbulence in ribbons of viscoelastic Taylor-Couette flow.

    PubMed

    Latrache, Noureddine; Abcha, Nizar; Crumeyrolle, Olivier; Mutabazi, Innocent

    2016-04-01

    Transition to defect-mediated turbulence in the ribbon patterns observed in a viscoelastic Taylor-Couette flow is investigated when the rotation rate of the inner cylinder is increased while the outer cylinder is fixed. In four polymer solutions with different values of the elasticity number, the defects appear just above the onset of the ribbon pattern and trigger the appearance of disordered oscillations when the rotation rate is increased. The flow structure around the defects is determined and the statistical properties of these defects are analyzed in the framework of the complex Ginzburg-Landau equation.

  19. Nanoparticle Controlled Soft Complex Structures with Topological Defects

    DTIC Science & Technology

    2013-10-01

    Condensed matter analogues of cosmology 25, 404201-1-404201-10, (2013); 7) Appl. Opt. 52, E47-E52 (2013); 8) Appl. Phys. Lett. 103, 143116 (2013...analogy with cosmology and magnetism, J. Phys.: Condens. Matter, Special Issue on Condensed matter analogues of cosmology 25, 404201, (2013). [24] A

  20. Luminescence properties of defects in GaN

    NASA Astrophysics Data System (ADS)

    Reshchikov, Michael A.; Morkoç, Hadis

    2005-03-01

    Gallium nitride (GaN) and its allied binaries InN and AIN as well as their ternary compounds have gained an unprecedented attention due to their wide-ranging applications encompassing green, blue, violet, and ultraviolet (UV) emitters and detectors (in photon ranges inaccessible by other semiconductors) and high-power amplifiers. However, even the best of the three binaries, GaN, contains many structural and point defects caused to a large extent by lattice and stacking mismatch with substrates. These defects notably affect the electrical and optical properties of the host material and can seriously degrade the performance and reliability of devices made based on these nitride semiconductors. Even though GaN broke the long-standing paradigm that high density of dislocations precludes acceptable device performance, point defects have taken the center stage as they exacerbate efforts to increase the efficiency of emitters, increase laser operation lifetime, and lead to anomalies in electronic devices. The point defects include native isolated defects (vacancies, interstitial, and antisites), intentional or unintentional impurities, as well as complexes involving different combinations of the isolated defects. Further improvements in device performance and longevity hinge on an in-depth understanding of point defects and their reduction. In this review a comprehensive and critical analysis of point defects in GaN, particularly their manifestation in luminescence, is presented. In addition to a comprehensive analysis of native point defects, the signatures of intentionally and unintentionally introduced impurities are addressed. The review discusses in detail the characteristics and the origin of the major luminescence bands including the ultraviolet, blue, green, yellow, and red bands in undoped GaN. The effects of important group-II impurities, such as Zn and Mg on the photoluminescence of GaN, are treated in detail. Similarly, but to a lesser extent, the effects of

  1. Carney Complex: an update

    PubMed Central

    Correa, Ricardo; Salpea, Paraskevi; Stratakis, Constantine

    2015-01-01

    Carney Complex (CNC) is a rare autosomal dominant syndrome, characterized by pigmented lesions of the skin and mucosa, cardiac, cutaneous and other myxomas, and multiple endocrine tumors. The disease is caused by inactivating mutations or large deletions of the PRKAR1A gene located at 17q22–24 coding for the regulatory subunit type I alpha of protein kinase A (PKA) gene. Most recently, components of the complex have been associated with defects of other PKA subunits, such as the catalytic subunits PRKACA (adrenal hyperplasia) and PRKACB (pigmented spots, myxomas, pituitary adenomas). In this report, we review CNC, its clinical features, diagnosis, treatment, and molecular etiology including PRKAR1A mutations and the newest on PRKACA and PRKACB defects especially as they pertain to adrenal tumors and Cushing’s syndrome. PMID:26130139

  2. Defect CFTs and holographic multiverse

    SciTech Connect

    Fiol, Bartomeu, E-mail: bfiol@ub.edu

    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 AdSmore » dual, although it might be possible if the defect supports a non-unitary theory.« less

  3. Detection of paint polishing defects

    NASA Astrophysics Data System (ADS)

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

    2018-06-01

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

  4. Characterization of oxygen defects in diamond by means of density functional theory calculations

    NASA Astrophysics Data System (ADS)

    Thiering, Gergő; Gali, Adam

    2016-09-01

    Point defects in diamond are of high interest as candidates for realizing solid state quantum bits, bioimaging agents, or ultrasensitive electric or magnetic field sensors. Various artificial diamond synthesis methods should introduce oxygen contamination in diamond, however, the incorporation of oxygen into diamond crystal and the nature of oxygen-related point defects are largely unknown. Oxygen may be potentially interesting as a source of quantum bits or it may interact with other point defects which are well established solid state qubits. Here we employ plane-wave supercell calculations within density functional theory, in order to characterize the electronic and magneto-optical properties of various oxygen-related defects. Besides the trivial single interstitial and substitutional oxygen defects we also consider their complexes with vacancies and hydrogen atoms. We find that oxygen defects are mostly electrically active and introduce highly correlated orbitals that pose a challenge for density functional theory modeling. Nevertheless, we are able to identify the fingerprints of substitutional oxygen defect, the oxygen-vacancy and oxygen-vacancy-hydrogen complexes in the electron paramagnetic resonance spectrum. We demonstrate that first principles calculations can predict the motional averaging of the electron paramagnetic resonance spectrum of defects that are subject to Jahn-Teller distortion. We show that the high-spin neutral oxygen-vacancy defect exhibits very fast nonradiative decay from its optical excited state that might hinder applying it as a qubit.

  5. Theoretical Study of Defect Signatures in III-V and II-VI Semiconductors

    DTIC Science & Technology

    2006-03-01

    collaboration with experimentalists at Linköpin University (Sweden), we identified the recently observed EPR signals in diluted GaPN to be Gallium ...the results from USPP calculations to all electron calculations. o Study NO-Zni complexes and other point defects in ZnO using USPP calculations...parameters for point defects in semiconductors. o Results on stability of NO-Zni complexes in ZnO and preliminary results on their electronic

  6. Interface effects on calculated defect levels for oxide defects

    NASA Astrophysics Data System (ADS)

    Edwards, Arthur; Barnaby, Hugh; Schultz, Peter; Pineda, Andrew

    2014-03-01

    Density functional theory (DFT) has had impressive recent success predicting defect levels in insulators and semiconductors [Schultz and von Lillienfeld, 2009]. Such success requires care in accounting for long-range electrostatic effects. Recently, Komsa and Pasquarello have started to address this problem in systems with interfaces. We report a multiscale technique for calculating electrostatic energies for charged defects in oxide of the metal-oxide-silicon (MOS) system, but where account is taken of substrate doping density, oxide thickness, and gate bias. We use device modeling to calculate electric fields for a point charge a fixed distance from the interface, and used the field to numerically calculate the long-range electrostatic interactions. We find, for example, that defect levels in the oxide do depend on both the magnitude and the polarity the substrate doping density. Furthermore, below 20 Å, oxide thickness also has significant effects. So, transferring results directly from bulk calculations leads to inaccuracies up to 0.5 eV- half of the silicon band gap. We will present trends in defect levels as a function of device parameters. We show that these results explain previous experimental results, and we comment on their potential impact on models for NBTI. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the United States Department of Energy's National Nuclear Security Administration under co.

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

    SciTech Connect

    Qingbang, Han; Ling, Chen; Changping, Zhu

    2014-02-18

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

  8. Effect of dose and size on defect engineering in carbon cluster implanted silicon wafers

    NASA Astrophysics Data System (ADS)

    Okuyama, Ryosuke; Masada, Ayumi; Shigematsu, Satoshi; Kadono, Takeshi; Hirose, Ryo; Koga, Yoshihiro; Okuda, Hidehiko; Kurita, Kazunari

    2018-01-01

    Carbon-cluster-ion-implanted defects were investigated by high-resolution cross-sectional transmission electron microscopy toward achieving high-performance CMOS image sensors. We revealed that implantation damage formation in the silicon wafer bulk significantly differs between carbon-cluster and monomer ions after implantation. After epitaxial growth, small and large defects were observed in the implanted region of carbon clusters. The electron diffraction pattern of both small and large defects exhibits that from bulk crystalline silicon in the implanted region. On the one hand, we assumed that the silicon carbide structure was not formed in the implanted region, and small defects formed because of the complex of carbon and interstitial silicon. On the other hand, large defects were hypothesized to originate from the recrystallization of the amorphous layer formed by high-dose carbon-cluster implantation. These defects are considered to contribute to the powerful gettering capability required for high-performance CMOS image sensors.

  9. 7 CFR 42.106 - Classifying and recording defects.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... container is scored only once for these two defects since the rust condition can be atributed to the leak... “leaker” (a critical defect) and not as “pitted rust” (a major defect). (2) Unrelated defects are defects...

  10. 7 CFR 42.106 - Classifying and recording defects.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... container is scored only once for these two defects since the rust condition can be attributed to the leak... “leaker” (a critical defect) and not as “pitted rust” (a major defect). (2) Unrelated defects are defects...

  11. 7 CFR 42.106 - Classifying and recording defects.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... container is scored only once for these two defects since the rust condition can be atributed to the leak... “leaker” (a critical defect) and not as “pitted rust” (a major defect). (2) Unrelated defects are defects...

  12. 7 CFR 42.106 - Classifying and recording defects.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... container is scored only once for these two defects since the rust condition can be atributed to the leak... “leaker” (a critical defect) and not as “pitted rust” (a major defect). (2) Unrelated defects are defects...

  13. 7 CFR 42.106 - Classifying and recording defects.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... container is scored only once for these two defects since the rust condition can be atributed to the leak... “leaker” (a critical defect) and not as “pitted rust” (a major defect). (2) Unrelated defects are defects...

  14. Dynamic defect correlations dominate activated electronic transport in SrTiO3

    PubMed Central

    Snijders, Paul C.; Şen, Cengiz; McConnell, Michael P.; Ma, Ying-Zhong; May, Andrew F.; Herklotz, Andreas; Wong, Anthony T.; Ward, T. Zac

    2016-01-01

    Strontium titanate (SrTiO3, STO) is a critically important material for the study of emergent electronic phases in complex oxides, as well as for the development of applications based on their heterostructures. Despite the large body of knowledge on STO, there are still many uncertainties regarding the role of defects in the properties of STO, including their influence on ferroelectricity in bulk STO and ferromagnetism in STO-based heterostructures. We present a detailed analysis of the decay of persistent photoconductivity in STO single crystals with defect concentrations that are relatively low but significantly affect their electronic properties. The results show that photo-activated electron transport cannot be described by a superposition of the properties due to independent point defects as current models suggest but is, instead, governed by defect complexes that interact through dynamic correlations. These results emphasize the importance of defect correlations for activated electronic transport properties of semiconducting and insulating perovskite oxides. PMID:27443503

  15. Carrier providers or killers: The case of Cu defects in CdTe

    DOE PAGES

    Yang, Ji -Hui; Metzger, Wyatt K.; Wei, Su -Huai

    2017-07-24

    Defects play important roles in semiconductors for optoelectronic applications. Common intuition is that defects with shallow levels act as carrier providers and defects with deep levels are carrier killers. Here, taking the Cu defects in CdTe as an example, we show that relatively shallow defects can play both roles. Using first-principles calculation methods combined with thermodynamic simulations, we study the dialectic effects of Cu-related defects on hole density and lifetime in bulk CdTe. Because CuCd can form a relatively shallow acceptor, we find that increased Cu incorporation into CdTe indeed can help achieve high hole density; however, too much Cumore » can cause significant non-radiative recombination. We discuss strategies to balance the contradictory effects of Cu defects based on the calculated impact of Cd chemical potential, copper defect concentrations, and annealing temperature on lifetime and hole density. Lastly, these findings advance the understanding of the potential complex defect behaviors of relatively shallow defect states in semiconductors.« less

  16. Carrier providers or killers: The case of Cu defects in CdTe

    SciTech Connect

    Yang, Ji -Hui; Metzger, Wyatt K.; Wei, Su -Huai

    Defects play important roles in semiconductors for optoelectronic applications. Common intuition is that defects with shallow levels act as carrier providers and defects with deep levels are carrier killers. Here, taking the Cu defects in CdTe as an example, we show that relatively shallow defects can play both roles. Using first-principles calculation methods combined with thermodynamic simulations, we study the dialectic effects of Cu-related defects on hole density and lifetime in bulk CdTe. Because CuCd can form a relatively shallow acceptor, we find that increased Cu incorporation into CdTe indeed can help achieve high hole density; however, too much Cumore » can cause significant non-radiative recombination. We discuss strategies to balance the contradictory effects of Cu defects based on the calculated impact of Cd chemical potential, copper defect concentrations, and annealing temperature on lifetime and hole density. Lastly, these findings advance the understanding of the potential complex defect behaviors of relatively shallow defect states in semiconductors.« less

  17. Periodontal regeneration in gingival recession defects.

    PubMed

    Trombelli, L

    1999-02-01

    Surgical treatment of gingival recession defects aims at obtaining soft tissue coverage of exposed root surfaces and/or augmentation of gingival tissue dimensions. A variety of protocols have been developed to manage these clinical problems. Since one goal of periodontal therapy is the regeneration of the lost attachment apparatus of the tooth, full restoration of defect should be accomplished following mucogingival procedures. This implies regeneration of all periodontal structures, including formation of new cementum with inserting connective tissue fibers, alveolar bone regeneration and recreation of a functional and aesthetic morphology of the mucogingival complex. Animal and human histological studies have shown that healing at gingiva-root interface following pedicle flaps or free soft tissue grafts generally includes a long junctional epithelium with varying amounts of a new connective tissue attachment in the most apical aspect of the covered root surface. Limited bone regeneration has been observed. Adjunctive use of root conditioning agents and cell excluding, wound-stabilizing devices may amplify regenerative outcomes. Changes in the amount of keratinized tissue, which can significantly affect the aesthetic outcome of treatment, have been shown to depend on the interactions among various tissues involved in the healing process and the selected surgical procedure.

  18. Neural Tube Defects, Folic Acid and Methylation

    PubMed Central

    Imbard, Apolline; Benoist, Jean-François; Blom, Henk J.

    2013-01-01

    Neural tube defects (NTDs) are common complex congenital malformations resulting from failure of the neural tube closure during embryogenesis. It is established that folic acid supplementation decreases the prevalence of NTDs, which has led to national public health policies regarding folic acid. To date, animal studies have not provided sufficient information to establish the metabolic and/or genomic mechanism(s) underlying human folic acid responsiveness in NTDs. However, several lines of evidence suggest that not only folates but also choline, B12 and methylation metabolisms are involved in NTDs. Decreased B12 vitamin and increased total choline or homocysteine in maternal blood have been shown to be associated with increased NTDs risk. Several polymorphisms of genes involved in these pathways have also been implicated in risk of development of NTDs. This raises the question whether supplementation with B12 vitamin, betaine or other methylation donors in addition to folic acid periconceptional supplementation will further reduce NTD risk. The objective of this article is to review the role of methylation metabolism in the onset of neural tube defects. PMID:24048206

  19. Fabric defect detection based on faster R-CNN

    NASA Astrophysics Data System (ADS)

    Liu, Zhoufeng; Liu, Xianghui; Li, Chunlei; Li, Bicao; Wang, Baorui

    2018-04-01

    In order to effectively detect the defects for fabric image with complex texture, this paper proposed a novel detection algorithm based on an end-to-end convolutional neural network. First, the proposal regions are generated by RPN (regional proposal Network). Then, Fast Region-based Convolutional Network method (Fast R-CNN) is adopted to determine whether the proposal regions extracted by RPN is a defect or not. Finally, Soft-NMS (non-maximum suppression) and data augmentation strategies are utilized to improve the detection precision. Experimental results demonstrate that the proposed method can locate the fabric defect region with higher accuracy compared with the state-of- art, and has better adaptability to all kinds of the fabric image.

  20. Defect controlled magnetism in FeP/graphene/Ni(111)

    PubMed Central

    Bhandary, Sumanta; Eriksson, Olle; Sanyal, Biplab

    2013-01-01

    Spin switching of organometallic complexes by ferromagnetic surfaces is an important topic in the area of molecular nanospintronics. Moreover, graphene has been shown as a 2D surface for physisorption of molecular magnets and strain engineering on graphene can tune the spin state of an iron porphyrin (FeP) molecule from S = 1 to S = 2. Our ab initio density functional calculations suggest that a pristine graphene layer placed between a Ni(111) surface and FeP yields an extremely weak exchange interaction between FeP and Ni whereas the introduction of defects in graphene shows a variety of ferromagnetic and antiferromagnetic exchange interactions. Moreover, these defects control the easy axes of magnetization, strengths of magnetic anisotropy energies and spin-dipolar contributions. Our study suggests a new way of manipulating molecular magnetism by defects in graphene and hence has the potential to be explored in designing spin qubits to realize logic operations in molecular nanospintronics. PMID:24296980

  1. Thermodynamics of surface defects at the aspirin/water interface

    NASA Astrophysics Data System (ADS)

    Schneider, Julian; Zheng, Chen; Reuter, Karsten

    2014-09-01

    We present a simulation scheme to calculate defect formation free energies at a molecular crystal/water interface based on force-field molecular dynamics simulations. To this end, we adopt and modify existing approaches to calculate binding free energies of biological ligand/receptor complexes to be applicable to common surface defects, such as step edges and kink sites. We obtain statistically accurate and reliable free energy values for the aspirin/water interface, which can be applied to estimate the distribution of defects using well-established thermodynamic relations. As a show case we calculate the free energy upon dissolving molecules from kink sites at the interface. This free energy can be related to the solubility concentration and we obtain solubility values in excellent agreement with experimental results.

  2. Rabbit Calvarial Defect Model for Customized 3D-Printed Bone Grafts.

    PubMed

    Lee, Kang-Gon; Lee, Kang-Sik; Kang, Yu-Jeoung; Hwang, Jong-Hyun; Lee, Se-Hwan; Park, Sang-Hyug; Park, Yongdoo; Cho, Young-Sam; Lee, Bu-Kyu

    2018-05-01

    Bone graft materials are commonly used to regenerate various bone defects, but their application is often limited because of the complex defect shape in various clinical conditions. Hence, customized bone grafts using three-dimensional (3D) printing techniques have been developed. However, conventional simple bone defect models are limited for evaluating the benefits and manufacturing accuracy of 3D-printed customized bone grafts. Thus, the aim of the present study was to develop a complex-shaped bone defect model. We designed an 8-shaped bony defect that consists of two simple circles attached to the rabbit calvarium. To determine the critical-sized defect (CSD) of the 8-shaped defects, 5.6- and 7-mm-diameter trephine burs were tested, and the 7-mm-diameter bur could successfully create a CSD, which was easily reproducible on the rabbit calvarium. The rate of new bone formation was 28.65% ± 8.63% at 16 weeks following creation of the defect. To confirm its efficacy for clinical use, the 8-shaped defect was created on a rabbit calvarium and 3D computed tomography (CT) was performed. A stereolithography file was produced using the CT data, and a 3D-printed polycaprolactone graft was fabricated. Using our 8-shaped defect model, we were able to modify the tolerances of the bone graft and calvarial defect to fabricate a more precise bone graft. Customized characteristics of the bone graft were then used to improve the accuracy of the bone graft. In addition, we confirmed the fitting ability of the 3D-printed graft during implantation of the graft. Our 8-shaped defect model on the rabbit calvarium using a 7.0-mm trephine bur may be a useful CSD model for evaluating 3D-printed graft materials.

  3. Improving reticle defect disposition via fully automated lithography simulation

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  4. Kinematic space for conical defects

    NASA Astrophysics Data System (ADS)

    Cresswell, Jesse C.; Peet, Amanda W.

    2017-11-01

    Kinematic space can be used as an intermediate step in the AdS/CFT dictionary and lends itself naturally to the description of diffeomorphism invariant quantities. From the bulk it has been defined as the space of boundary anchored geodesics, and from the boundary as the space of pairs of CFT points. When the bulk is not globally AdS3 the appearance of non-minimal geodesics leads to ambiguities in these definitions. In this work conical defect spacetimes are considered as an example where non-minimal geodesics are common. From the bulk it is found that the conical defect kinematic space can be obtained from the AdS3 kinematic space by the same quotient under which one obtains the defect from AdS3. The resulting kinematic space is one of many equivalent fundamental regions. From the boundary the conical defect kinematic space can be determined by breaking up OPE blocks into contributions from individual bulk geodesics. A duality is established between partial OPE blocks and bulk fields integrated over individual geodesics, minimal or non-minimal.

  5. Delamination initiated by a defect

    NASA Astrophysics Data System (ADS)

    Biel, A.; Toftegaard, H.

    2016-07-01

    Composite materials in wind turbines are mainly joined with adhesives. Adhesive joining is preferable since it distributes the stresses over a larger area. This study shows how a defect can influence the fracture behaviour of adhesively joined composite. Repeated experiments are performed using double cantilever beam specimens loaded with bending moments. The specimens consist of two 8 mm thick GFRP-laminates which are joined by a 3 mm thick epoxy adhesive. A thin foil close to one of the laminates is used to start the crack. For some of the specimens a defect is created by an initial load-unload operation. During this operation, a clamp is used in order to prevent crack propagation in the main direction. For the specimens without defect, the crack propagates in the middle of the adhesive layer. For the specimens with defect, the crack directly deviates into the laminate. After about 25 mm propagation in the laminate, the crack returns to the adhesive. Compared to the adhesive the fracture energy for the laminate is significantly higher.

  6. What Are Congenital Heart Defects?

    MedlinePlus

    ... surgery to close an atrial septal defect? This study tests a tool that allows surgeons to tell the difference between various types of heart tissue and avoid injury. To participate in this study, your child must be between 30 days and ...

  7. Characterization of point defects in monolayer arsenene

    NASA Astrophysics Data System (ADS)

    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.

  8. Analyzing the defect structure of CuO-doped PZT and KNN piezoelectrics from electron paramagnetic resonance.

    PubMed

    Jakes, Peter; Kungl, Hans; Schierholz, Roland; Eichel, Rüdiger-A

    2014-09-01

    The defect structure for copper-doped sodium potassium niobate (KNN) ferroelectrics has been analyzed with respect to its defect structure. In particular, the interplay between the mutually compensating dimeric (Cu(Nb)'''-V(O)··) and trimeric (V(O)··-Cu(Nb)'''-V(O)··)· defect complexes with 180° and non-180° domain walls has been analyzed and compared to the effects from (Cu'' - V(O)··)(x)× dipoles in CuO-doped lead zirconate titanate (PZT). Attempts are made to relate the rearrangement of defect complexes to macroscopic electromechanical properties.

  9. Impaired Mitochondrial Dynamics Underlie Axonal Defects in Hereditary Spastic Paraplegias.

    PubMed

    Denton, Kyle; Mou, Yongchao; Xu, Chong-Chong; Shah, Dhruvi; Chang, Jaerak; Blackstone, Craig; Li, Xue-Jun

    2018-05-02

    Mechanisms by which long corticospinal axons degenerate in hereditary spastic paraplegia (HSP) are largely unknown. Here, we have generated induced pluripotent stem cells (iPSCs) from patients with two autosomal recessive forms of HSP, SPG15 and SPG48, which are caused by mutations in the ZFYVE26 and AP5Z1 genes encoding proteins in the same complex, the spastizin and AP5Z1 proteins, respectively. In patient iPSC-derived telencephalic glutamatergic and midbrain dopaminergic neurons, neurite number, length and branching are significantly reduced, recapitulating disease-specific phenotypes. We analyzed mitochondrial morphology and noted a significant reduction in both mitochondrial length and their densities within axons of these HSP neurons. Mitochondrial membrane potential was also decreased, confirming functional mitochondrial defects. Notably, mdivi-1, an inhibitor of the mitochondrial fission GTPase DRP1, rescues mitochondrial morphology defects and suppresses the impairment in neurite outgrowth and late-onset apoptosis in HSP neurons. Furthermore, knockdown of these HSP genes causes similar axonal defects, also mitigated by treatment with mdivi-1. Finally, neurite outgrowth defects in SPG15 and SPG48 cortical neurons can be rescued by knocking down DRP1 directly. Thus, abnormal mitochondrial morphology caused by an imbalance of mitochondrial fission and fusion underlies specific axonal defects and serves as a potential therapeutic target for SPG15 and SPG48.

  10. [Locoregional solutions for groin defects : Coverage after vascular surgery].

    PubMed

    Cerny, M; Harder, Y; Zimmermann, A; Eckstein, H-H; Machens, H-G; Schantz, J-T; Schenck, T L

    2017-01-01

    Vascular surgery through a groin incision may be associated with severe wound healing disorders in this sensitive area. There are many options to reconstruct the defect surgically. The choice of surgical reconstruction depends mainly on the individual status of vasculature, which is most often compromised in these patients. There are random pattern flaps, as well as perforator, pedicled flaps or microvascular flaps to choose from. We give an overview of plastic surgical solutions for groin defects, with a special focus on complex wounds after vascular surgical complications. We discuss advantages and disadvantages of different flaps with two case reports and also show alternatives. We demonstrate in two cases how the reconstruction of the groin defect was planned, taking into account the vascular status, and why we chose an innovative and seldom-used option in each case. The selected flaps, a pedicled fasciocutaneous ALT propeller flap and a perforator-based, pedicled abdominal advancement flap reconstructed the defects successfully. The surgical therapy for the reconstruction of groin defects should be chosen according to the individual vascular status to ensure safe and reliable blood supply. To guarantee the best possible reconstruction and avoid postoperative healing disorders and infections, less common flaps should also be considered.

  11. Orientational order of motile defects in active nematics

    DOE PAGES

    DeCamp, Stephen J.; Redner, Gabriel S.; Baskaran, Aparna; ...

    2015-08-17

    The study of equilibrium liquid crystals has led to fundamental insights into the nature of ordered materials, as well as many practical applications such as display technologies. Active nematics are a fundamentally different class of liquid crystals, which are driven away from equilibrium by the autonomous motion of their constituent rodlike particles. This internally-generated activity powers the continuous creation and annihilation of topological defects, leading to complex streaming flows whose chaotic dynamics appear to destroy long-range order. Here, we study these dynamics in experimental and computational realizations of active nematics. By tracking thousands of defects over centimeter distances in microtubule-basedmore » active nematics, we identify a non-equilibrium phase characterized by system-spanning orientational order of defects. This emergent order persists over hours despite defect lifetimes of only seconds. Lastly, similar dynamical structures are observed in coarse-grained simulations, suggesting that defect-ordered phases are a generic feature of active nematics.« less

  12. Divacancy-tin related defects in irradiated germanium

    NASA Astrophysics Data System (ADS)

    Khirunenko, L. I.; Sosnin, M. G.; Duvanskii, A. V.; Abrosimov, N. V.; Riemann, H.

    2018-04-01

    A new absorption spectrum has been detected in the region of 770-805 cm-1 following the annealing of low temperature irradiated Sn-doped Ge. The spectrum develops simultaneously with the disappearance of the V2-related absorption band. The new spectra arise both in p- (doping with gallium) and n- (doping with antimony) type samples and are completely identical to the absorption spectrum of the corresponding dopants. The studies have shown that the defects responsible for the registered spectra have hydrogen-like excited states similar to those observed for hydrogen-like group-III acceptors and group-V donors in Ge. The defects are identified as SnV2Ga and SnV2Sb. The formation of the revealed complexes consists of two stages. During the first stage, the defects are created as a result of the direct interaction of SnV2 diffusing upon the annealing with atoms Ga or Sb. The second stage arises, apparently, due to the participation of SnV2 in the formation of intermediate defects that are optically inactive and transform into the revealed defects at annealing temperatures Tann. > 243 K.

  13. Defective pulmonary innervation and autonomic imbalance in congenital diaphragmatic hernia

    PubMed Central

    Lath, Nikesh R.; Galambos, Csaba; Rocha, Alejandro Best; Malek, Marcus; Gittes, George K.

    2012-01-01

    Congenital diaphragmatic hernia (CDH) is associated with significant mortality due to lung hypoplasia and pulmonary hypertension. The role of embryonic pulmonary innervation in normal lung development and lung maldevelopment in CDH has not been defined. We hypothesize that developmental defects of intrapulmonary innervation, in particular autonomic innervation, occur in CDH. This abnormal embryonic pulmonary innervation may contribute to lung developmental defects and postnatal physiological derangement in CDH. To define patterns of pulmonary innervation in CDH, human CDH and control lung autopsy specimens were stained with the pan-neural marker S-100. To further characterize patterns of overall and autonomic pulmonary innervation during lung development in CDH, the murine nitrofen model of CDH was utilized. Immunostaining for protein gene product 9.5 (a pan-neuronal marker), tyrosine hydroxylase (a sympathetic marker), vesicular acetylcholine transporter (a parasympathetic marker), or VIP (a parasympathetic marker) was performed on lung whole mounts and analyzed via confocal microscopy and three-dimensional reconstruction. Peribronchial and perivascular neuronal staining pattern is less complex in human CDH than control lung. In mice, protein gene product 9.5 staining reveals less complex neuronal branching and decreased neural tissue in nitrofen-treated lungs from embryonic day 12.5 to 16.5 compared with controls. Furthermore, nitrofen-treated embryonic lungs exhibited altered autonomic innervation, with a relative increase in sympathetic nerve staining and a decrease in parasympathetic nerve staining compared with controls. These results suggest a primary defect in pulmonary neural developmental in CDH, resulting in less complex neural innervation and autonomic imbalance. Defective embryonic pulmonary innervation may contribute to lung developmental defects and postnatal physiological derangement in CDH. PMID:22114150

  14. Simulations of defect spin qubits in piezoelectric semiconductors

    NASA Astrophysics Data System (ADS)

    Seo, Hosung

    In recent years, remarkable advances have been reported in the development of defect spin qubits in semiconductors for solid-state quantum information science and quantum metrology. Promising spin qubits include the nitrogen-vacancy center in diamond, dopants in silicon, and the silicon vacancy and divacancy spins in silicon carbide. In this talk, I will highlight some of our recent efforts devoted to defect spin qubits in piezoelectric wide-gap semiconductors for potential applications in mechanical hybrid quantum systems. In particular, I will describe our recent combined theoretical and experimental study on remarkably robust quantum coherence found in the divancancy qubits in silicon carbide. We used a quantum bath model combined with a cluster expansion method to identify the microscopic mechanisms behind the unusually long coherence times of the divacancy spins in SiC. Our study indicates that developing spin qubits in complex crystals with multiple types of atom is a promising route to realize strongly coherent hybrid quantum systems. I will also discuss progress and challenges in computational design of new spin defects for use as qubits in piezoelectric crystals such as AlN and SiC, including a new defect design concept using large metal ion - vacancy complexes. Our first principles calculations include DFT computations using recently developed self-consistent hybrid density functional theory and large-scale many-body GW theory. This work was supported by the National Science Foundation (NSF) through the University of Chicago MRSEC under Award Number DMR-1420709.

  15. Influence of chemical disorder on energy dissipation and defect evolution in concentrated solid solution alloys

    PubMed Central

    Zhang, Yanwen; Stocks, G. Malcolm; Jin, Ke; Lu, Chenyang; Bei, Hongbin; Sales, Brian C.; Wang, Lumin; Béland, Laurent K.; Stoller, Roger E.; Samolyuk, German D.; Caro, Magdalena; Caro, Alfredo; Weber, William J.

    2015-01-01

    A grand challenge in materials research is to understand complex electronic correlation and non-equilibrium atomic interactions, and how such intrinsic properties and dynamic processes affect energy transfer and defect evolution in irradiated materials. Here we report that chemical disorder, with an increasing number of principal elements and/or altered concentrations of specific elements, in single-phase concentrated solid solution alloys can lead to substantial reduction in electron mean free path and orders of magnitude decrease in electrical and thermal conductivity. The subsequently slow energy dissipation affects defect dynamics at the early stages, and consequentially may result in less deleterious defects. Suppressed damage accumulation with increasing chemical disorder from pure nickel to binary and to more complex quaternary solid solutions is observed. Understanding and controlling energy dissipation and defect dynamics by altering alloy complexity may pave the way for new design principles of radiation-tolerant structural alloys for energy applications. PMID:26507943

  16. Ordered defect compounds in CuInSe{sub 2} for photovoltaic solar cell application

    SciTech Connect

    Sato, K.; Katayama-Yoshida, H.

    2014-02-21

    Due to the complete compensation, defect complex (2V{sub Cu}+In{sub Cu}), namely two Cu vacancies and In located at Cu site, is stable in CuInSe{sub 2} (CIS). It is known that the series of ordered defect compounds (ODC) are constracted by ordering the defect complex. Based on the total energy calcalation by using the Korringa-Kohn-Rostoker coherent potential approxiamtion (KKR-CPA) method, we discuss phase separation of the CIS with the defect complexes into ODC and CIS. Since the band alignment between ODC and CIS is calculated to be type 2, effective electron-hole separation at the interface between ODC and CIS can bemore » expected. This causes the enhancement of conversion efficiency of CIS-based solar cell materials.« less

  17. Automated mask and wafer defect classification using a novel method for generalized CD variation measurements

    NASA Astrophysics Data System (ADS)

    Verechagin, V.; Kris, R.; Schwarzband, I.; Milstein, A.; Cohen, B.; Shkalim, A.; Levy, S.; Price, D.; Bal, E.

    2018-03-01

    Over the years, mask and wafers defects dispositioning has become an increasingly challenging and time consuming task. With design rules getting smaller, OPC getting complex and scanner illumination taking on free-form shapes - the probability of a user to perform accurate and repeatable classification of defects detected by mask inspection tools into pass/fail bins is reducing. The critical challenging of mask defect metrology for small nodes ( < 30 nm) was reviewed in [1]. While Critical Dimension (CD) variation measurement is still the method of choice for determining a mask defect future impact on wafer, the high complexity of OPCs combined with high variability in pattern shapes poses a challenge for any automated CD variation measurement method. In this study, a novel approach for measurement generalization is presented. CD variation assessment performance is evaluated on multiple different complex shape patterns, and is benchmarked against an existing qualified measurement methodology.

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

    Treesearch

    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-...

  19. Modeling defect trends for iterative development

    NASA Technical Reports Server (NTRS)

    Powell, J. D.; Spanguolo, J. N.

    2003-01-01

    The Employment of Defects (EoD) approach to measuring and analyzing defects seeks to identify and capture trends and phenomena that are critical to managing software quality in the iterative software development lifecycle at JPL.

  20. Facts about Atrioventricular Septal Defect (AVSD)

    MedlinePlus

    ... Living With Heart Defects Data & Statistics Tracking & Research Articles & Key Findings Free Materials Multimedia and Tools Links to Other Websites Information For… Media Policy Makers Facts about Atrioventricular Septal Defect (AVSD) ...

  1. Cell and defect behavior in lithium-counterdoped solar cells

    NASA Technical Reports Server (NTRS)

    Weinberg, I.; Mehta, S.; Swartz, C. K.

    1984-01-01

    Some n(+)/p cells in which lithium is introduced as a counterdopant, by ion-implantation, into the cell's boron-doped p-region were studied. To determine if the cells radiation resistance could be significantly improved by lithium counterdoping. Defect behavior was related to cell performance using deep level transient spectroscopy. Results indicate a significantly increased radiation resistance for the lithium counterdoped cells when compared to the boron doped 1 ohm-cm control cell. The increased radiation resistance of the lithium counterdoped cells is due to the complexing of lithium with divacancies and boron. It is speculated that complexing with oxygen and single vacancies also contributes to the increased radiation resistance. Counterdoping silicon with lithium results in a different set of defects.

  2. Generic equilibration dynamics of planar defects in trapped atomic superfluids

    DOE PAGES

    Scherpelz, Peter; Padavić, Karmela; Murray, Andy; ...

    2015-03-18

    Here, we investigate equilibration processes shortly after sudden perturbations are applied to ultracold trapped superfluids. We show the similarity of phase imprinting and localized density depletion perturbations, both of which initially are found to produce “phase walls”. These planar defects are associated with a sharp gradient in the phase. Importantly they relax following a quite general sequence. Our studies, based on simulations of the complex time-dependent Ginzburg-Landau equation, address the challenge posed by these experiments: how a superfluid eventually eliminatesa spatially extended planar defect. The processes involved are necessarily more complex than equilibration involving simpler line vortices. An essential mechanismmore » form relaxation involves repeated formation and loss of vortex rings near the trap edge.« less

  3. Automatic classification of blank substrate defects

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

  4. Defect tolerant transmission lithography mask

    DOEpatents

    Vernon, Stephen P.

    2000-01-01

    A transmission lithography mask that utilizes a transparent substrate or a partially transparent membrane as the active region of the mask. A reflective single layer or multilayer coating is deposited on the membrane surface facing the illumination system. The coating is selectively patterned (removed) to form transmissive (bright) regions. Structural imperfections and defects in the coating have negligible effect on the aerial image of the mask master pattern since the coating is used to reflect radiation out of the entrance pupil of the imaging system. Similarly, structural imperfections in the clear regions of the membrane have little influence on the amplitude or phase of the transmitted electromagnetic fields. Since the mask "discards," rather than absorbs, unwanted radiation, it has reduced optical absorption and reduced thermal loading as compared to conventional designs. For EUV applications, the mask circumvents the phase defect problem, and is independent of the thermal load during exposure.

  5. Is Migraine A Lateralisation Defect?

    PubMed Central

    Kaaro, Jani; Partonen, Timo; Naik, Paulami; Hadjikhani, Nouchine

    2008-01-01

    Migraine often co-occurs with patent foramen ovale (PFO) and some have suggested surgical closure as an efficient treatment for migraine. However, prospective studies do not report radical effect of PFO surgery on migraine. Here we examined the hypothesis that PFO and migraine may co-occur as two independent manifestations of lateralization defect during embryonic development. We measured the absolute displacement of a midline structure, the pineal gland, on brain scans of 39 migraineurs and 26 controls. We found a significant asymmetry of the pineal gland in migraineurs compared with controls. Our data suggest that migraine's circadian component and its association with PFO may be linked to a lateralization defect during embryogenesis, which could be a result from abnormal serotonin regulation. PMID:18695522

  6. Cooperation and Defection in Ghetto

    NASA Astrophysics Data System (ADS)

    Kułakowski, Krzysztof

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

  7. Topological defects in open string field theory

    NASA Astrophysics Data System (ADS)

    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.

  8. Inspection of lithographic mask blanks for defects

    DOEpatents

    Sommargren, Gary E.

    2001-01-01

    A visible light method for detecting sub-100 nm size defects on mask blanks used for lithography. By using optical heterodyne techniques, detection of the scattered light can be significantly enhanced as compared to standard intensity detection methods. The invention is useful in the inspection of super-polished surfaces for isolated surface defects or particulate contamination and in the inspection of lithographic mask or reticle blanks for surface defects or bulk defects or for surface particulate contamination.

  9. Various Stone-Wales defects in phagraphene

    NASA Astrophysics Data System (ADS)

    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. A Study of Defect Behavior in Almandine Garnet

    NASA Astrophysics Data System (ADS)

    Geiger, C. A.; Brearley, A. J.; Dachs, E.; Tipplet, G.; Rossman, G. R.

    2016-12-01

    Transport and diffusion in crystals are controlled by defects. However, a good understanding of the defect types in many silicates, including garnet, is not at hand. We undertook a study on synthetic almandine, ideal end-member Fe3Al2Si3O12, to better understand its precise chemical and physical properties and defect behavior. Crystals were synthesized at high pressures and temperatures under different fO2 conditions using various starting materials with H2O and without. The almandine obtained came in polycrystalline and single-crystal form. The synthetic reaction products and crystals were carefully characterized using X-ray powder diffraction, electron microprobe and TEM analysis and with 57Fe Mössbauer, UV/VIS single-crystal absorption and IR single-crystal spectroscopy. Various possible intrinsic defects, such as the Frenkel, Schottky and site-disorder types, along with Fe3+, in both synthetic and natural almandine crystals, were analyzed based on model defects expressed in Kröger-Vink notation. Certain types of minor microscopic- to macroscopic-sized precipitation or exsolution phases, including some that are nanosized, that are observed in synthetic almandine (e.g., magnetite), as well as in more compositionally complex natural crystals (e.g., magnetite, rutile, ilmenite), may result from defect reactions. An explanation for their origin through minor amounts of defects in garnet has certain advantages over other models that have been put forth in the literature that assume strict garnet stoichiometry for their formation and/or open-system atomic transport over relatively long length scales. Physical properties, including magnetic, electrical conductivity and diffusion behavior, as well as the color, of almandine are also analyzed in terms of various possible model defects. It is difficult, if not impossible, to synthesize stoichiometric end-member almandine, Fe3Al2Si3O12, in the laboratory, as small amounts of extrinsic OH- and/or Fe3+ defects, for example

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

    NASA Astrophysics Data System (ADS)

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

    2017-10-01

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

  12. Intentional defect array wafers: their practical use in semiconductor control and monitoring systems

    NASA Astrophysics Data System (ADS)

    Emami, Iraj; McIntyre, Michael; Retersdorf, Michael

    2003-07-01

    In the competitive world of semiconductor manufacturing today, control of the process and manufacturing equipment is paramount to success of the business. Consistent with the need for rapid development of process technology, is a need for development wiht respect to equipment control including defect metrology tools. Historical control methods for defect metrology tools included a raw count of defects detected on a characterized production or test wafer with little or not regard to the attributes of the detected defects. Over time, these characterized wafers degrade with multiple passes on the tools and handling requiring the tool owner to create and characterize new samples periodically. With the complex engineering software analysis systems used today, there is a strong reliance on the accuracy of defect size, location, and classification in order to provide the best value when correlating the in line to sort type of data. Intentional Defect Array (IDA) wafers were designed and manufacturered at International Sematech (ISMT) in Austin, Texas and is a product of collaboration between ISMT member companies and suppliers of advanced defect inspection equipment. These wafers provide the use with known defect types and sizes in predetermined locations across the entire wafer. The wafers are designed to incorporate several desired flows and use critical dimensions consistent with current and future technology nodes. This paper briefly describes the design of the IDA wafer and details many practical applications in the control of advanced defect inspection equipment.

  13. Stabilization of primary mobile radiation defects in MgF2 crystals

    NASA Astrophysics Data System (ADS)

    Lisitsyn, V. M.; Lisitsyna, L. A.; Popov, A. I.; Kotomin, E. A.; Abuova, F. U.; Akilbekov, A.; Maier, J.

    2016-05-01

    Non-radiative decay of the electronic excitations (excitons) into point defects (F-H pairs of Frenkel defects) is main radiation damage mechanism in many ionic (halide) solids. Typical time scale of the relaxation of the electronic excitation into a primary, short-lived defect pair is about 1-50 ps with the quantum yield up to 0.2-0.8. However, only a small fraction of these primary defects are spatially separated and survive after transformation into stable, long-lived defects. The survival probability (or stable defect accumulation efficiency) can differ by orders of magnitude, dependent on the material type; e.g. ∼10% in alkali halides with f.c.c. or b.c.c. structure, 0.1% in rutile MgF2 and <0.001% in fluorides MeF2 (Me: Ca, Sr, Ba). The key factor determining accumulation of stable radiation defects is stabilization of primary defects, first of all, highly mobile hole H centers, through their transformation into more complex immobile defects. In this talk, we present the results of theoretical calculations of the migration energies of the F and H centers in poorely studied MgF2 crystals with a focus on the H center stabilization in the form of the interstitial F2 molecules which is supported by presented experimental data.

  14. Method for mask repair using defect compensation

    DOEpatents

    Sweeney, Donald W.; Ray-Chaudhuri, Avijit K.

    2001-01-01

    A method for repair of amplitude and/or phase defects in lithographic masks. The method involves modifying or altering a portion of the absorber pattern on the surface of the mask blank proximate to the mask defect to compensate for the local disturbance (amplitude or phase) of the optical field due to the defect.

  15. Templates Aid Removal Of Defects From Castings

    NASA Technical Reports Server (NTRS)

    Hendrickson, Robert G.

    1992-01-01

    Templates used to correlate defects in castings with local wall thicknesses. Placed on part to be inspected after coated with penetrant dye. Positions of colored spots (indicative of defects) noted. Ultrasonic inspector measures thickness of wall at unacceptable defects only - overall inspection not necessary.

  16. Annihilating nanoscale defects | Argonne National Laboratory

    Science.gov Websites

    molecules must follow to find defect-free states and designed a process that delivers industry-standard predict the path molecules must follow to find defect-free states and designed a process that delivers deeper than others. The system prefers defect-free stability, which can be characterized by the deepest

  17. Investigation of hydrogen interaction with defects in zirconia

    NASA Astrophysics Data System (ADS)

    Melikhova, O.; Kuriplach, J.; Čížek, J.; Procházka, I.; Brauer, G.; Anwand, W.

    2010-04-01

    Defect studies of a ZrO2 + 9 mol. % Y2O3 single crystal were performed in this work using a high resolution positron lifetime spectroscopy combined with slow positron implantation spectroscopy. In order to elucidate the nature of positron trapping sites observed experimentally, the structural relaxations of several types of vacancy-like defects in zirconia were performed and positron characteristics for them were calculated. Relaxed atomic configurations of studied defects were obtained by means of ab initio pseudopotential method within the supercell approach. Theoretical calculations indicated that neither oxygen vacancies nor their neutral complexes with substitute yttrium atoms are capable of positron trapping. On the other hand, zirconium vacancies are deep positron traps and are most probably responsible for the saturated positron trapping observed in yttria stabilized zirconia single crystals. However, the calculated positron lifetime for zirconium vacancy is apparently longer than the experimental value corresponding to a single-component spectrum measured for the cubic ZrO2 + 9 mol. % Y2O3 single crystal. It was demonstrated that this effect can be explained by hydrogen trapped in zirconium vacancies. On the basis of structure relaxations, we found that zirconium vacancy - hydrogen complexes represent deep positron traps with the calculated lifetime close to the experimental one. In zirconium vacancy - hydrogen complexes the hydrogen atom forms an O-H bond with one of the nearest neighbour oxygen atoms. The calculated bond length is close to 1 Å.

  18. Photographic guide of selected external defect indicators and associated internal defects in northern red oak

    Treesearch

    Everette D. Rast

    1982-01-01

    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 aids the individual in identifying the surface defect indicator and also shows the progressive stages of the defect throughout its development. It illustrates and describes eight types...

  19. Photographic guide to selected external defect indicators and associated internal defects in black cherry

    Treesearch

    Everette D. Rast; John A. Beaton; John A. Beaton

    1985-01-01

    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 aids the individual in identifying the surface defect indicator and also shows the progressive stages of the defect throughout its development for black cherry. It illustrates and...

  20. Photographic guide to selected external defect indicators and associated internal defects in black walnut

    Treesearch

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

    1988-01-01

    To properly classify qr 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 aids the individual in identifying the surface defect indicator and also shows the progressive stages of the defect throughout its develqpment for black walnut. It illustrates and...

  1. Photographic guide of selected external defect indicators and associated internal defects in white oak

    Treesearch

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

    1989-01-01

    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 also shows the progressive stages of the defect throughout its development for white oak. It illustrates and...

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

    Treesearch

    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...

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

    Treesearch

    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...

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

    Treesearch

    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...

  5. Optimizing reconstruction of oncologic sternectomy defects based on surgical outcomes.

    PubMed

    Butterworth, James A; Garvey, Patrick B; Baumann, Donald P; Zhang, Hong; Rice, David C; Butler, Charles E

    2013-08-01

    The optimal strategy for oncologic sternectomy reconstruction has not been well characterized. We hypothesized that the major factors driving the reconstructive strategy for oncologic sternectomy include the need for skin replacement, extent of the bony sternectomy defect, and status of the internal mammary vessels. We reviewed consecutive oncologic sternectomy reconstructions performed at The University of Texas MD Anderson Cancer Center during a 10-year period. Regression models analyzed associations between patient, defect, and treatment factors and outcomes to identify patient and treatment selection criteria. We developed a generalized management algorithm based on these data. Forty-nine consecutive patients underwent oncologic sternectomy reconstruction (mean follow-up 18 ± 23 months). More sternectomies were partial (74%) rather than total/subtotal (26%). Most defects (n = 40 [82%]) required skeletal reconstruction. Pectoralis muscle flaps were most commonly used for sternectomies with intact overlying skin (64%) and infrequently used when a presternal skin defect was present (36%; p = 0.06). Free flaps were more often used for total/subtotal vs partial sternectomy defects (75% vs 25%, respectively; p = 0.02). Complication rates for total/subtotal sternectomy and partial sternectomy were equivalent (46% vs 44%, respectively; p = 0.92). Despite more extensive sternal resections, total/subtotal sternectomies resulted in equivalent postoperative complications when combined with the appropriate soft-tissue reconstruction. Good surgical and oncologic outcomes can be achieved with defect-characteristic-matched reconstructive strategies for these complex oncologic sternectomy resections. Copyright © 2013 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

  6. Vacancy-oxygen defects in p-type Si1-xGex

    NASA Astrophysics Data System (ADS)

    Sgourou, E. N.; Londos, C. A.; Chroneos, A.

    2014-10-01

    Oxygen-vacancy defects and, in particular, the VO pairs (known as A-centers) are common defects in silicon (Si) with a deleterious impact upon its properties. Although oxygen-vacancy defects have been extensively studied in Si there is far less information about their properties in p-type doped silicon germanium (Si1-xGex). Here, we use Fourier transform infrared spectroscopy to determine the production and evolution of oxygen-vacancy defects in p-type Si1-xGex. It was determined that the increase of Ge content affects the production and the annealing behavior of the VO defect as well as its conversion to the VO2 defect. In particular, both the VO production and the VO annealing temperature are reduced with the increase of Ge. The conversion ratio [VO2]/[VO] also decreases with the increase of x, although the ratios [VO3]/[VO2] and [VO4]/[VO3] show a tendency to increase for larger Ge contents. The results are discussed in view of recent experimental and theoretical studies in Si and Si1-xGex.

  7. Defect levels of semi-insulating CdMnTe:In crystals

    NASA Astrophysics Data System (ADS)

    Kim, K. H.; Bolotinikov, A. E.; Camarda, G. S.; Hossain, A.; Gul, R.; Yang, G.; Cui, Y.; Prochazka, J.; Franc, J.; Hong, J.; James, R. B.

    2011-06-01

    Using photoluminescence (PL) and current deep-level transient spectroscopy (I-DLTS), we investigated the electronic defects of indium-doped detector-grade CdMnTe:In (CMT:In) crystals grown by the vertical Bridgman method. We similarly analyzed CdZnTe:In (CZT:In) and undoped CdMnTe (CMT) crystals grown under the amount of same level of excess Te and/or indium doping level to detail the fundamental properties of the electronic defect structure more readily. Extended defects, existing in all the samples, were revealed by synchrotron white beam x-ray diffraction topography and scanning electron microscopy. The electronic structure of CMT is very similar to that of CZT, with shallow traps, A-centers, Cd vacancies, deep levels, and Te antisites. The 1.1-eV deep level, revealed by PL in earlier studies of CZT and CdTe, were attributed to dislocation-induced defects. In our I-DLTS measurements, the 1.1-eV traps showed different activation energies with applied bias voltage and an exponential dependence on the trap-filling time, which are typical characteristics of dislocation-induced defects. We propose a new defect-trap model for indium-doped CMT crystals.

  8. Effects of Stone-Wales and vacancy defects in atomic-scale friction on defective graphite

    SciTech Connect

    Sun, Xiao-Yu; Key Laboratory of Hubei Province for Water Jet Theory and New Technology, Wuhan University, Wuhan 430072; Wu, RunNi

    2014-05-05

    Graphite is an excellent solid lubricant for surface coating, but its performance is significantly weakened by the vacancy or Stone-Wales (SW) defect. This study uses molecular dynamics simulations to explore the frictional behavior of a diamond tip sliding over a graphite which contains a single defect or stacked defects. Our results suggest that the friction on defective graphite shows a strong dependence on defect location and type. The 5-7-7-5 structure of SW defect results in an effectively negative slope of friction. For defective graphite containing a defect in the surface, adding a single vacancy in the interior layer will decreasemore » the friction coefficients, while setting a SW defect in the interior layer may increase the friction coefficients. Our obtained results may provide useful information for understanding the atomic-scale friction properties of defective graphite.« less

  9. Weak scratch detection and defect classification methods for a large-aperture optical element

    NASA Astrophysics Data System (ADS)

    Tao, Xian; Xu, De; Zhang, Zheng-Tao; Zhang, Feng; Liu, Xi-Long; Zhang, Da-Peng

    2017-03-01

    Surface defects on optics cause optic failure and heavy loss to the optical system. Therefore, surface defects on optics must be carefully inspected. This paper proposes a coarse-to-fine detection strategy of weak scratches in complicated dark-field images. First, all possible scratches are detected based on bionic vision. Then, each possible scratch is precisely positioned and connected to a complete scratch by the LSD and a priori knowledge. Finally, multiple scratches with various types can be detected in dark-field images. To classify defects and pollutants, a classification method based on GIST features is proposed. This paper uses many real dark-field images as experimental images. The results show that this method can detect multiple types of weak scratches in complex images and that the defects can be correctly distinguished with interference. This method satisfies the real-time and accurate detection requirements of surface defects.

  10. Tight-binding calculation studies of vacancy and adatom defects in graphene

    SciTech Connect

    Zhang, Wei; Lu, Wen-Cai; Zhang, Hong-Xing

    2016-02-19

    Computational studies of complex defects in graphene usually need to deal with a larger number of atoms than the current first-principles methods can handle. We show a recently developed three-center tight-binding potential for carbon is very efficient for large scale atomistic simulations and can accurately describe the structures and energies of various defects in graphene. Using the three-center tight-binding potential, we have systematically studied the stable structures and formation energies of vacancy and embedded-atom defects of various sizes up to 4 vacancies and 4 embedded atoms in graphene. In conclusion, our calculations reveal low-energy defect structures and provide a moremore » comprehensive understanding of the structures and stability of defects in graphene.« less

  11. Non-monotonic temperature dependence of radiation defect dynamics in silicon carbide

    DOE PAGES

    Bayu Aji, L. B.; Wallace, J. B.; Shao, L.; ...

    2016-08-03

    Understanding response of solids to particle irradiation remains a major materials physics challenge. This applies even to SiC, which is a prototypical nuclear ceramic and wide-band-gap semiconductor material. The lack of predictability is largely related to the complex, dynamic nature of radiation defect formation. Here, we use a novel pulsed-ion-beam method to study dynamic annealing in 4H-SiC ion-bombarded in the temperature range of 25–250 °C. We find that, while the defect recombination efficiency shows an expected monotonic increase with increasing temperature, the defect lifetime exhibits a non-monotonic temperature dependence with a maximum at ~100 °C. This finding indicates a changemore » in the dominant defect interaction mechanism at ~100 °C. As a result, the understanding of radiation defect dynamics may suggest new paths to designing radiation-resistant materials.« less

  12. Non-monotonic temperature dependence of radiation defect dynamics in silicon carbide

    SciTech Connect

    Bayu Aji, L. B.; Wallace, J. B.; Shao, L.

    Understanding response of solids to particle irradiation remains a major materials physics challenge. This applies even to SiC, which is a prototypical nuclear ceramic and wide-band-gap semiconductor material. The lack of predictability is largely related to the complex, dynamic nature of radiation defect formation. Here, we use a novel pulsed-ion-beam method to study dynamic annealing in 4H-SiC ion-bombarded in the temperature range of 25–250 °C. We find that, while the defect recombination efficiency shows an expected monotonic increase with increasing temperature, the defect lifetime exhibits a non-monotonic temperature dependence with a maximum at ~100 °C. This finding indicates a changemore » in the dominant defect interaction mechanism at ~100 °C. As a result, the understanding of radiation defect dynamics may suggest new paths to designing radiation-resistant materials.« less

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

    NASA Astrophysics Data System (ADS)

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

    2018-04-01

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

  14. Resist process optimization for further defect reduction

    NASA Astrophysics Data System (ADS)

    Tanaka, Keiichi; Iseki, Tomohiro; Marumoto, Hiroshi; Takayanagi, Koji; Yoshida, Yuichi; Uemura, Ryouichi; Yoshihara, Kosuke

    2012-03-01

    Defect reduction has become one of the most important technical challenges in device mass-production. Knowing that resist processing on a clean track strongly impacts defect formation in many cases, we have been trying to improve the track process to enhance customer yield. For example, residual type defect and pattern collapse are strongly related to process parameters in developer, and we have reported new develop and rinse methods in the previous papers. Also, we have reported the optimization method of filtration condition to reduce bridge type defects, which are mainly caused by foreign substances such as gels in resist. Even though we have contributed resist caused defect reduction in past studies, defect reduction requirements continue to be very important. In this paper, we will introduce further process improvements in terms of resist defect reduction, including the latest experimental data.

  15. Carbon, oxygen and intrinsic defect interactions in germanium-doped silicon

    NASA Astrophysics Data System (ADS)

    Londos, C. A.; Sgourou, E. N.; Chroneos, A.; Emtsev, V. V.

    2011-10-01

    Production and annealing of oxygen-vacancy (VO) and oxygen-carbon (CiOi, CiOiI) defects in germanium-doped Czochralski-grown silicon (Cz-Si) containing carbon are investigated. All the samples were irradiated with 2 MeV fast electrons. Radiation-produced defects are studied using infrared spectroscopy by monitoring the relevant bands in optical spectra. For the VO defects, it is established that the doping with Ge affects the thermal stability of VO (830 cm-1) defects as well as their fraction converted to VO2 (888 cm-1) defects. In Ge-free samples containing carbon, it was found that carbon impurity atoms do not affect the thermal stability of VO defects, although they affect the fraction of VO defects that is converted to VO2 complexes. Considering the oxygen-carbon complexes, it is established that the annealing of the 862 cm-1 band associated with the CiOi defects is accompanied with the emergence of the 1048 cm-1 band, which has earlier been assigned to the CsO2i center. The evolution of the CiOiI bands is also traced. Ge doping does not seem to affect the thermal stability of the CiOi and CiOiI defects. Density functional theory (DFT) calculations provide insights into the stability of the defect clusters (VO, CiOi, CiOiI) at an atomic level. Both experimental and theoretical results are consistent with the viewpoint that Ge affects the stability of the VO but does not influence the stability of the oxygen-carbon clusters. DFT calculations demonstrate that C attracts both Oi and VO pairs predominately forming next nearest neighbor clusters in contrast to Ge where the interactions with Oi and VO are more energetically favorable at nearest neighbor configurations.

  16. Atomic Approaches to Defect Thermochemistry

    DTIC Science & Technology

    1992-04-30

    from the enthalpy of melting of ison with real experiments by a factor of Au to be 29 meV. (We have checked that the 2.1x10 3; the time scale of the...Diffusion and to Map Vacancy Concentrations at a Fixed Time V. Studies of Electroluminescent Flat-Panel Display Devices VI. Defect Characterization VII...kT), where n = ND - NA is the doping density, about the same time that P. Mei et al. published the first experimental report of this effect (Appl. Phys

  17. Algorithms and applications of aberration correction and American standard-based digital evaluation in surface defects evaluating system

    NASA Astrophysics Data System (ADS)

    Wu, Fan; Cao, Pin; Yang, Yongying; Li, Chen; Chai, Huiting; Zhang, Yihui; Xiong, Haoliang; Xu, Wenlin; Yan, Kai; Zhou, Lin; Liu, Dong; Bai, Jian; Shen, Yibing

    2016-11-01

    The inspection of surface defects is one of significant sections of optical surface quality evaluation. Based on microscopic scattering dark-field imaging, sub-aperture scanning and stitching, the Surface Defects Evaluating System (SDES) can acquire full-aperture image of defects on optical elements surface and then extract geometric size and position information of defects with image processing such as feature recognization. However, optical distortion existing in the SDES badly affects the inspection precision of surface defects. In this paper, a distortion correction algorithm based on standard lattice pattern is proposed. Feature extraction, polynomial fitting and bilinear interpolation techniques in combination with adjacent sub-aperture stitching are employed to correct the optical distortion of the SDES automatically in high accuracy. Subsequently, in order to digitally evaluate surface defects with American standard by using American military standards MIL-PRF-13830B to judge the surface defects information obtained from the SDES, an American standard-based digital evaluation algorithm is proposed, which mainly includes a judgment method of surface defects concentration. The judgment method establishes weight region for each defect and adopts the method of overlap of weight region to calculate defects concentration. This algorithm takes full advantage of convenience of matrix operations and has merits of low complexity and fast in running, which makes itself suitable very well for highefficiency inspection of surface defects. Finally, various experiments are conducted and the correctness of these algorithms are verified. At present, these algorithms have been used in SDES.

  18. Real-time defect detection on highly reflective curved surfaces

    NASA Astrophysics Data System (ADS)

    Rosati, G.; Boschetti, G.; Biondi, A.; Rossi, A.

    2009-03-01

    This paper presents an automated defect detection system for coated plastic components for the automotive industry. This research activity came up as an evolution of a previous study which employed a non-flat mirror to illuminate and inspect high reflective curved surfaces. According to this method, the rays emitted from a light source are conveyed on the surface under investigation by means of a suitably curved mirror. After the reflection on the surface, the light rays are collected by a CCD camera, in which the coating defects appear as shadows of various shapes and dimensions. In this paper we present an evolution of the above-mentioned method, introducing a simplified mirror set-up in order to reduce the costs and the complexity of the defect detection system. In fact, a set of plane mirrors is employed instead of the curved one. Moreover, the inspection of multiple bend radius parts is investigated. A prototype of the machine vision system has been developed in order to test this simplified method. This device is made up of a light projector, a set of plane mirrors for light rays reflection, a conveyor belt for handling components, a CCD camera and a desktop PC which performs image acquisition and processing. Like in the previous system, the defects are identified as shadows inside a high brightness image. At the end of the paper, first experimental results are presented.

  19. Topological defects in confined populations of spindle-shaped cells

    NASA Astrophysics Data System (ADS)

    Duclos, Guillaume; Erlenkämper, Christoph; Joanny, Jean-François; Silberzan, Pascal

    2017-01-01

    Most spindle-shaped cells (including smooth muscles and sarcomas) organize in vivo into well-aligned `nematic’ domains, creating intrinsic topological defects that may be used to probe the behaviour of these active nematic systems. Active non-cellular nematics have been shown to be dominated by activity, yielding complex chaotic flows. However, the regime in which live spindle-shaped cells operate, and the importance of cell-substrate friction in particular, remains largely unexplored. Using in vitro experiments, we show that these active cellular nematics operate in a regime in which activity is effectively damped by friction, and that the interaction between defects is controlled by the system’s elastic nematic energy. Due to the activity of the cells, these defects behave as self-propelled particles and pairwise annihilate until all displacements freeze as cell crowding increases. When confined in mesoscopic circular domains, the system evolves towards two identical +1/2 disclinations facing each other. The most likely reduced positions of these defects are independent of the size of the disk, the cells’ activity or even the cell type, but are well described by equilibrium liquid crystal theory. These cell-based systems thus operate in a regime more stable than other active nematics, which may be necessary for their biological function.

  20. Challenges in the reconstruction of bilateral maxillectomy defects.

    PubMed

    Joseph, Shawn T; Thankappan, Krishnakumar; Buggaveeti, Rahul; Sharma, Mohit; Mathew, Jimmy; Iyer, Subramania

    2015-02-01

    Bilateral maxillectomy defects, if not adequately reconstructed, can result in grave esthetic and functional problems. The purpose of this study was to investigate the outcome of reconstruction of such defects. This is a retrospective case series. The defects were analyzed for their components and the flaps used for reconstruction. Outcomes for flap loss and functional indices, including oral diet, speech, and dental rehabilitation, also were evaluated. Ten consecutive patients who underwent bilateral maxillectomy reconstruction received 14 flaps. Six patients had malignancies of the maxilla, and 4 patients had nonmalignant indications. Ten bony free flaps were used. Four soft tissue flaps were used. The fibula free flap was the most common flap used. Three patients had total flap loss. Seven patients were alive and available for functional evaluation. Of these, 4 were taking an oral diet with altered consistency and 2 were on a regular diet. Speech was intelligible in all patients. Only 2 patients opted for dental rehabilitation with removable dentures. Reconstruction after bilateral maxillectomy is essential to prevent esthetic and functional problems. Bony reconstruction is ideal. The fibula bone free flap is commonly used. The complexity of the defect makes reconstruction difficult and the initial success rate of free flaps is low. Secondary reconstructions after the initial flap failures were successful. A satisfactory functional outcome can be achieved. Copyright © 2015 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  1. Electronic properties of defects in silicon and related materials

    NASA Astrophysics Data System (ADS)

    Mitromara, Niki

    Efforts in the current semiconductor industry are focused on the production of smaller, more efficient and inexpensive devices of higher packing density. As silicon is the dominant semiconductor implemented for the fabrication of the majority of semiconductor devices, perpetual research has focused on the improvement of its properties and the realisation of the most efficient structures. This thesis presents the electrical characterisation of two different diode structures that are important for the present and future generations of electronic devices.The first part of the thesis is focused on the electrical characterisation of Ultra-Shallow Junction (USJs) Si diodes. Both p+n and n+p USJ structures that contained different implants were examined. These were very highly doped and intended to simulate the situation where a doping well is formed after heavy doping in Si for the fabrication of transistors currently used in Complementary-Metal-Oxide-Semiconductor (CMOS) technology. The implanted USJ diodes were provided by NXP, Belgium and contact deposition was performed before their electrical characterisation as part of this project. Subsequently the p+n and n+p USJ diodes were characterised by the use of Capacitance-Voltage (CV), Current-Voltage (IV), Deep Level Transient Spectroscopy (DLTS) and high resolution Laplace DLTS (LDLTS). DLTS and LDLTS are very powerful spectroscopic techniques for the profiling of defects in the bandgap of a semiconductor as well as for the identification of the electrical signatures of these defects. Transient-Enhanced Diffusion (TED) related defects were detected in these diodes as the presence of mainly carbon-related interstitial complexes was observed. In addition, certain vacancy or vacancy-dopant related levels were also discerned.The second part of this thesis presents the electrical characterisation from Schottky p-diamond/p-Si and p-diamond/n-Si p-n diodes. These diodes were readily provided, grown by the Chemical Vapour

  2. A fast button surface defects detection method based on convolutional neural network

    NASA Astrophysics Data System (ADS)

    Liu, Lizhe; Cao, Danhua; Wu, Songlin; Wu, Yubin; Wei, Taoran

    2018-01-01

    Considering the complexity of the button surface texture and the variety of buttons and defects, we propose a fast visual method for button surface defect detection, based on convolutional neural network (CNN). CNN has the ability to extract the essential features by training, avoiding designing complex feature operators adapted to different kinds of buttons, textures and defects. Firstly, we obtain the normalized button region and then use HOG-SVM method to identify the front and back side of the button. Finally, a convolutional neural network is developed to recognize the defects. Aiming at detecting the subtle defects, we propose a network structure with multiple feature channels input. To deal with the defects of different scales, we take a strategy of multi-scale image block detection. The experimental results show that our method is valid for a variety of buttons and able to recognize all kinds of defects that have occurred, including dent, crack, stain, hole, wrong paint and uneven. The detection rate exceeds 96%, which is much better than traditional methods based on SVM and methods based on template match. Our method can reach the speed of 5 fps on DSP based smart camera with 600 MHz frequency.

  3. Vacancy defects in electron-irradiated ZnO studied by Doppler broadening of annihilation radiation

    NASA Astrophysics Data System (ADS)

    Chen, Z. Q.; Betsuyaku, K.; Kawasuso, A.

    2008-03-01

    Vacancy defects in ZnO induced by electron irradiation were characterized by the Doppler broadening of annihilation radiation measurements together with the local density approximation calculations. Zinc vacancies (VZn) are responsible for positron trapping in the as-irradiated state. These are annealed out below 200°C . The further annealing at 400°C results in the formation of secondary defects attributed to the complexes composed of zinc vacancies and zinc antisites (VZn-ZnO) .

  4. Injectable Reactive Biocomposites For Bone Healing In Critical-Size Rabbit Calvarial Defects

    DTIC Science & Technology

    2012-03-29

    defects (i.e. be conformable), provide temporary protection to the brain until the bone heals, and enhance tissue regeneration with the delivery of...temporary protection to the brain until the bone heals, and enhance tissue regeneration with the delivery of biologics. In this study, we evaluated the...complex defects (i.e. be conformable), harden to provide temporary protection until tissue remodels (i.e. be settable), and enhance tissue regeneration

  5. Magnetoencephalography signals are influenced by skull defects.

    PubMed

    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.

  6. Operator product expansion for conformal defects

    NASA Astrophysics Data System (ADS)

    Fukuda, Masayuki; Kobayashi, Nozomu; Nishioka, Tatsuma

    2018-01-01

    We study the operator product expansion (OPE) for scalar conformal defects of any codimension in CFT. The OPE for defects is decomposed into "defect OPE blocks", the irreducible representations of the conformal group, each of which packages the contribution from a primary operator and its descendants. We use the shadow formalism to deduce an integral representation of the defect OPE blocks. They are shown to obey a set of constraint equations that can be regarded as equations of motion for a scalar field propagating on the moduli space of the defects. By employing the Radon transform between the AdS space and the moduli space, we obtain a formula of constructing an AdS scalar field from the defect OPE block for a conformal defect of any codimension in a scalar representation of the conformal group, which turns out to be the Euclidean version of the HKLL formula. We also introduce a duality between conformal defects of different codimensions and prove the equivalence between the defect OPE block for codimension-two defects and the OPE block for a pair of local operators.

  7. Defect engineering in Multinary Semiconductors

    NASA Astrophysics Data System (ADS)

    Radautsan, S. I.

    1993-12-01

    The last two decades have shown a rapid increase both in our knowledge of the multinary compounds and their applications in engineering. The remarkable scientific leaders from different countries Prof. N.A.Goryunova, M.Rodot, A. Rabenau, E. Parthe, P. Manca, K. Matsumoto, C. Schwab, R. Tomlinson, J. Woolley, W.T. Kim, T. Irie, A. Zunger, N. Joshi, E. Sato et al. made their valuable contribution to the problems of the classification,crystal chemistry,growing processes and characterizations of multinary compounds [1-3]. Most of them were technologically difficult and as a result it was very hard to obtain the crystals with reproducible parameters. It was therefore obvious the well coordinated efforts in the field of chemistry,physics and electronics to be required. In this paper we review some of the major original results to get the defective compounds suitable for fundamental research and electronic applications. The main attention is paid to such effects as non-stoichiometry, order-disorder phase transitions as well as to non-equilibrium treatment by employing different methods of the defect engineering.

  8. Ion channeling study of defects in compound crystals using Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Turos, A.; Jozwik, P.; Nowicki, L.; Sathish, N.

    2014-08-01

    Ion channeling is a well-established technique for determination of structural properties of crystalline materials. Defect depth profiles have been usually determined basing on the two-beam model developed by Bøgh (1968) [1]. As long as the main research interest was focused on single element crystals it was considered as sufficiently accurate. New challenge emerged with growing technological importance of compound single crystals and epitaxial heterostructures. Overlap of partial spectra due to different sublattices and formation of complicated defect structures makes the two beam method hardly applicable. The solution is provided by Monte Carlo computer simulations. Our paper reviews principal aspects of this approach and the recent developments in the McChasy simulation code. The latter made it possible to distinguish between randomly displaced atoms (RDA) and extended defects (dislocations, loops, etc.). Hence, complex defect structures can be characterized by the relative content of these two components. The next refinement of the code consists of detailed parameterization of dislocations and dislocation loops. Defect profiles for variety of compound crystals (GaN, ZnO, SrTiO3) have been measured and evaluated using the McChasy code. Damage accumulation curves for RDA and extended defects revealed non monotonous defect buildup with some characteristic steps. Transition to each stage is governed by the different driving force. As shown by the complementary high resolution XRD measurements lattice strain plays here the crucial role and can be correlated with the concentration of extended defects.

  9. Rapid surface defect detection based on singular value decomposition using steel strips as an example

    NASA Astrophysics Data System (ADS)

    Sun, Qianlai; Wang, Yin; Sun, Zhiyi

    2018-05-01

    For most surface defect detection methods based on image processing, image segmentation is a prerequisite for determining and locating the defect. In our previous work, a method based on singular value decomposition (SVD) was used to determine and approximately locate surface defects on steel strips without image segmentation. For the SVD-based method, the image to be inspected was projected onto its first left and right singular vectors respectively. If there were defects in the image, there would be sharp changes in the projections. Then the defects may be determined and located according sharp changes in the projections of each image to be inspected. This method was simple and practical but the SVD should be performed for each image to be inspected. Owing to the high time complexity of SVD itself, it did not have a significant advantage in terms of time consumption over image segmentation-based methods. Here, we present an improved SVD-based method. In the improved method, a defect-free image is considered as the reference image which is acquired under the same environment as the image to be inspected. The singular vectors of each image to be inspected are replaced by the singular vectors of the reference image, and SVD is performed only once for the reference image off-line before detecting of the defects, thus greatly reducing the time required. The improved method is more conducive to real-time defect detection. Experimental results confirm its validity.

  10. Prosthetic Rehabilitation of Defects of the Head and Neck

    PubMed Central

    Salinas, Thomas J.

    2010-01-01

    Patients afflicted with head and neck cancer, traumatic injuries to the head and neck, or those with congenital or developmental defects benefit from multidisciplinary team management. The head and neck region participates in complex physiologic processes that can often be impeded by these circumstances. Evaluation of the patient by the maxillofacial prosthodontist can assist the other members of the team in providing treatment planning options for the patients. Intraoral defects arising from these circumstances can be treated with prosthodontics that serve to assist with speech, swallowing, and to some degree mastication. If chemotherapeutic or radiation modalities are also used to treat the head and neck, assessment of the patient by the maxillofacial prosthodontist may prove to identify factors that may predispose to undesirable sequelae. Preventive treatment by elective tooth extraction, prosthodontic assessment, and patient education prove to assist in predictable management of these oftentimes complex presenting conditions. Facial defects arising from similar circumstances can be an alternative or adjunct to plastic surgical reconstruction and offer the added advantage of tumor surveillance in susceptible patients. PMID:22550451

  11. Effect of point defects on the amorphization of metallic alloys during ion implantation. [NiTi

    SciTech Connect

    Pedraza, D.F.; Mansur, L.K.

    1985-01-01

    A theoretical model of radiation-induced amorphization of ordered intermetallic compounds is developed. The mechanism is proposed to be the buildup of lattice defects to very high concentrations, which destabilizes the crystalline structure. Because simple point defects do not normally reach such levels during irradiation, a new defect complex containing a vacancy and an interstitial is hypothesized. Crucial properties of the complex are that the interstitial sees a local chemical environment similar to that of an atom in the ordered lattice, that the formation of the complex prevents mutual recombination and that the complex is immobile. The evolution of a disordermore » based on complexes is not accompanied by like point defect aggregation. The latter leads to the development of a sink microstructure in alloys that do not become amorphous. For electron irradiation, the complexes form by diffusional encounters. For ion irradiation, complexes are also formed directly in cascades. The possibility of direct amorphization in cascades is also included. Calculations for the compound NiTi show reasonable agreement with measured amorphization kinetics.« less

  12. Reconstruction of large cranial defects in the presence of heavy radiation damage and infection utilizing tissue transferred by microvascular anastomoses

    SciTech Connect

    Robson, M.C.; Zachary, L.S.; Schmidt, D.R.

    1989-03-01

    Six cases of large defects of the scalp, skull, and dura following tumor ablation and radiation are presented. Each was accompanied by chronic infection in the irradiated defect. Efforts to reconstruct the resulting defects with local flaps were not successful. One-stage reconstruction was then accomplished in each case utilizing a latissimus dorsi musculocutaneous or myo-osteocutaneous free flap transferred by microvascular anastomoses. The versatility of the latissimus dorsi musculocutaneous and/or osseous flap allows single-stage reconstruction of these complex defects.

  13. A study of vacancy defects related to gray tracks in KTiOPO{sub 4} (KTP) using positron annihilation

    SciTech Connect

    Zhang, Yang; Li, Jing; Wang, Jiyang, E-mail: hdjiang@sdu.edu.cn

    For the first time to our knowledge, positron annihilation spectroscopy (PAS) was used to study vacancy defects in KTiOPO{sub 4} (KTP) single crystals. Positron annihilation lifetime spectroscopy combined with dielectric measurements identified the existence of oxygen vacancies and reflected the concentration of vacancy defects in three samples. The vacancy defects in KTP do not consist of monovacancies, but rather vacancy complexes. Doppler broadening indicates that the vacancy defects are distributed uniformly. A relationship is established where a crystal with a low oxygen vacancy concentration and a highly balanced stoichiometry has a higher resistance to gray track formation.

  14. Enhanced thermoelectric performance of defected silicene nanoribbons

    NASA Astrophysics Data System (ADS)

    Zhao, W.; Guo, Z. X.; Zhang, Y.; Ding, J. W.; Zheng, X. J.

    2016-02-01

    Based on non-equilibrium Green's function method, we investigate the thermoelectric performance for both zigzag (ZSiNRs) and armchair (ASiNRs) silicene nanoribbons with central or edge defects. For perfect silicene nanoribbons (SiNRs), it is shown that with its width increasing, the maximum of ZT values (ZTM) decreases monotonously while the phononic thermal conductance increases linearly. For various types of edges and defects, with increasing defect numbers in longitudinal direction, ZTM increases monotonously while the phononic thermal conductance decreases. Comparing with ZSiNRs, defected ASiNRs possess higher thermoelectric performance due to higher Seebeck coefficient and lower thermal conductance. In particular, about 2.5 times enhancement to ZT values is obtained in ASiNRs with edge defects. Our theoretical simulations indicate that by controlling the type and number of defects, ZT values of SiNRs could be enhanced greatly which suggests their very appealing thermoelectric applications.

  15. Primordial inhomogeneities from massive defects during inflation

    SciTech Connect

    Firouzjahi, Hassan; Karami, Asieh; Rostami, Tahereh, E-mail: firouz@ipm.ir, E-mail: karami@ipm.ir, E-mail: t.rostami@ipm.ir

    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. Wemore » 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.« less

  16. Perception of risk from automobile safety defects.

    PubMed

    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.

  17. Defect-Engineered Metal–Organic Frameworks

    PubMed Central

    Fang, Zhenlan; Bueken, Bart; De Vos, Dirk E; Fischer, Roland A

    2015-01-01

    Defect engineering in metal–organic frameworks (MOFs) is an exciting concept for tailoring material properties, which opens up novel opportunities not only in sorption and catalysis, but also in controlling more challenging physical characteristics such as band gap as well as magnetic and electrical/conductive properties. It is challenging to structurally characterize the inherent or intentionally created defects of various types, and there have so far been few efforts to comprehensively discuss these issues. Based on selected reports spanning the last decades, this Review closes that gap by providing both a concise overview of defects in MOFs, or more broadly coordination network compounds (CNCs), including their classification and characterization, together with the (potential) applications of defective CNCs/MOFs. Moreover, we will highlight important aspects of “defect-engineering” concepts applied for CNCs, also in comparison with relevant solid materials such as zeolites or COFs. Finally, we discuss the future potential of defect-engineered CNCs. PMID:26036179

  18. Little string origin of surface defects

    NASA Astrophysics Data System (ADS)

    Haouzi, Nathan; Schmid, Christian

    2017-05-01

    We derive a large class of codimension-two defects of 4d \\mathcal{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 [1]. 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.

  19. Agricultural Compounds in Water and Birth Defects.

    PubMed

    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.

  20. Detection of tanker defects with infrared thermography

    NASA Technical Reports Server (NTRS)

    Kantsios, A. G.

    1980-01-01

    Infrared scanning technique for finding defects in secondary barrier of liquid natural gas (LNG) tank has been successfully tested on ship under construction at Newport News Shipbuilding and Dry Dock Company. Technique determines defects with minimal expenditure of time and manpower. Tests could be repeated during life of tanker and make more complicated testing unnecessary. Tests also confirmed that tank did not have any major defects, and tank was certified.

  1. Inferior sinus venosus defect: echocardiographic diagnosis and surgical approach.

    PubMed

    Crystal, Matthew A; Al Najashi, Khaled; Williams, William G; Redington, Andrew N; Anderson, Robert H

    2009-06-01

    We sought to define the inferior sinus venosus defect anatomically and document successful surgical approaches. We identified all patients previously given a diagnosis of an inferior sinus venosus defect at the Hospital for Sick Children, Toronto, Canada, between 1982 and 2005 by interrogating the cardiology and cardiac surgery databases. We included those having interatrial communications in which 1 or more of the right pulmonary veins drained to the inferior caval vein but retained connection with the left atrium, the rims of the oval fossa, and the walls of the coronary sinus, both being intact. We identified 11 children who had an interatrial communication meeting the criteria for and undergoing surgical repair of an inferior sinus venosus defect. Median age was 1.2 years; 6 (55%) subjects were male, and none were cyanotic. Transthoracic echocardiographic analysis was performed preoperatively in all children, revealing right ventricular dilation in all. Surgical repair was accomplished with a pericardial patch. A complex baffle was needed in 3 children to maintain unobstructed inferior caval and pulmonary venous return. The echocardiographic diagnosis was complete in only 5 patients, but all diagnoses were correct since the year 2000. In all children the observations at surgical intervention showed that the defect was a venoatrial communication involving drainage of the right pulmonary veins to the inferior caval vein while retaining connection to the left atrium. Transthoracic echocardiographic analysis should remain the modality of choice for diagnosis of the inferior sinus venosus defect. We report excellent surgical results with a patch or baffle, correctly redirecting the anomalous venoatrial connections.

  2. Defect identification in semiconductors with positron annihilation: experiment and theory

    NASA Astrophysics Data System (ADS)

    Tuomisto, Filip

    2015-03-01

    Positron annihilation spectroscopy is a very powerful technique for the detection, identification and quantification of vacancy-type defects in semiconductors. In the past decades, it has been used to reveal the relationship between opto-electronic properties and specific defects in a wide variety of materials - examples include parasitic yellow luminescence in GaN, dominant acceptor defects in ZnO and broad-band absorption causing brown coloration in natural diamond. In typical binary compound semiconductors, the selective sensitivity of the technique is rather strongly limited to cation vacancies that possess significant open volume and suitable charge (negative of neutral). On the other hand, oxygen vacancies in oxide semiconductors are a widely debated topic. The properties attributed to oxygen vacancies include the inherent n-type conduction, poor p-type dopability, coloration (absorption), deep level luminescence and non-radiative recombination, while the only direct experimental evidence of their existence has been obtained on the crystal surface. We will present recent advances in combining state-of-the-art positron annihilation experiments and ab initio computational approaches. The latter can be used to model both the positron lifetime and the electron-positron momentum distribution - quantities that can be directly compared with experimental results. We have applied these methods to study vacancy-type defects in III-nitride semiconductors (GaN, AlN, InN) and oxides such as ZnO, SnO2, In2O3andGa2O3. We will show that cation-vacancy-related defects are important compensating centers in all these materials when they are n-type. In addition, we will show that anion (N, O) vacancies can be detected when they appear as complexes with cation vacancies.

  3. Repair of tetralogy of Fallot associated with atrioventricular septal defect.

    PubMed

    Tláskal, T; Hucín, B; Kostelka, M; Chaloupecký, V; Marek, J; Tax, P; Janouàek, J; Kuèera, V; Hruda, J; Reich, O; Skovránek, J

    1998-01-01

    Tetralogy of Fallot, when associated with atrioventricular septal defect permitting shunting at ventricular level, represents a complex cyanotic congenital malformation. Experience with surgical repair is limited, and results vary considerably. Between 1984 and 1996, we repaired 14 consecutive patients with this combination seen in our center. Their ages ranged from 8 months to 21 years (median 7.4 years). Six (42.9%) had Down's syndrome. In eight patients the correct diagnosis was made using echocardiography alone. In the remaining six patients, who had previously-constructed arterial shunts and/or suspected pulmonary arterial stenosis, catheterization and angiocardiography were also performed. The repair consisted of double patch closure of the septal defect, reconstruction of two atrioventricular orifices, and relief of pulmonary stenosis at all levels. In five patients with a hypoplastic pulmonary trunk, a monocusp transannular patch (four patients) or an allograft (one patient) was used for restoration of continuity from the right ventricle to the pulmonary arteries. Patch enlargement of one or both pulmonary arteries was necessary in five patients. One patient (7.1%) died early, and another late. The twelve surviving (85.8%) patients have been followed for 1.2-12.5 years after surgery (median 4.9 years, mean 5.9+/-3.9 years). During the follow-up, reoperation was necessary for repair of residual ventricular septal defect and pulmonary regurgitation in two patients, and closure of an atrial septal defect and alteration to left atrioventricular valvar regurgitation in one patient. Seven patients are in class I of the New York Heart Association, four in class II, and one in class III. Tetralogy of Fallot associated with atrioventricular septal defect can be corrected with low mortality and good long-term results. Residual lesions, however, have a tendency to progress, especially when seen in combination. After surgery, all patients need long-term close follow-up.

  4. Stress-dependence of kinetic transitions at atomistic defects

    NASA Astrophysics Data System (ADS)

    Ball, S. L.; Alexander, K. C.; Schuh, C. A.

    2018-01-01

    The full second-rank activation volume tensors associated with vacancy migration in FCC copper and HCP titanium as well as transition events in the Σ5 (2 1 0) grain boundary in copper are calculated and analyzed. The full tensorial results quantitatively illustrate how the conventional use of an activation volume scalar in atomistic studies of the kinetic processes of complex defects can miss important stress dependencies, in that neither hydrostatic pressure nor deviatoric stress dependencies can be considered alone as dominating the response. The results speak to the importance of anisotropies in the stress-dependence of atomistic kinetics, including crystal structure anisotropy, elastic anisotropy, and defect structure or migration-path anisotropies.

  5. Defect-Induced Hedgehog Polarization States in Multiferroics

    NASA Astrophysics Data System (ADS)

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

    2018-03-01

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

  6. Defect-Induced Hedgehog Polarization States in Multiferroics.

    PubMed

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

    2018-03-30

    Continuous developments in nanotechnology require new approaches to materials synthesis that can produce novel functional structures. Here, we show that nanoscale defects, such as nonstoichiometric nanoregions (NSNRs), can act as nano-building blocks for creating complex electrical polarization structures in the prototypical multiferroic BiFeO_{3}. An array of charged NSNRs are produced in BiFeO_{3} thin films by tuning the substrate temperature during film growth. Atomic-scale scanning transmission electron microscopy imaging reveals exotic polarization rotation patterns around these NSNRs. These polarization patterns resemble hedgehog or vortex topologies and can cause local changes in lattice symmetries leading to mixed-phase structures resembling the morphotropic phase boundary with high piezoelectricity. Phase-field simulations indicate that the observed polarization configurations are mainly induced by charged states at the NSNRs. Engineering defects thus may provide a new route for developing ferroelectric- or multiferroic-based nanodevices.

  7. Positron trapping at defects in copper oxide superconductors

    NASA Astrophysics Data System (ADS)

    McMullen, T.; Jena, P.; Khanna, S. N.; Li, Yi; Jensen, Kjeld O.

    1991-05-01

    Positron states and lifetimes at defects in the copper oxide superconductors La2-xSrxCuO4, YBa2Cu3O7-x, and Bi2Sr2CaCu2O8+x are calculated with use of the superposed-atom model. In the Bi2Sr2CaCu2O8+x compound, we find that the smaller metal-ion vacancies appear to only bind positrons weakly, while missing oxygens do not trap positrons. In contrast, metal-ion vacancies in La2-xSrxCuO4 and YBa2Cu3O7-x bind positrons by ~1 eV, and oxygen-related defects appear to be the weak-binding sites in these materials. The sites that bind positrons only weakly, by energies ~kBT, are of particular interest in view of the complex temperature dependences of the annihilation characteristics that are observed in these materials.

  8. Luminescence from defects in GaN

    NASA Astrophysics Data System (ADS)

    Reshchikov, M. A.; Morkoç, H.

    2006-04-01

    We briefly review the luminescence properties of defects in GaN and focus on the most interesting defects. In particular, the blue luminescence band peaking at about 3 eV is assigned to different defects and even different types of transitions in undoped, Zn-, C-, and Mg-doped GaN. Another omnipresent luminescence band, the yellow luminescence band may have different origin in nearly dislocation-free freestanding GaN templates, undoped thin layers, and carbon-doped GaN. The Y4 and Y7 lines are caused by recombination at unidentified point defects captured by threading edge dislocations.

  9. Automatic thermographic image defect detection of composites

    NASA Astrophysics Data System (ADS)

    Luo, Bin; Liebenberg, Bjorn; Raymont, Jeff; Santospirito, SP

    2011-05-01

    Detecting defects, and especially reliably measuring defect sizes, are critical objectives in automatic NDT defect detection applications. In this work, the Sentence software is proposed for the analysis of pulsed thermography and near IR images of composite materials. Furthermore, the Sentence software delivers an end-to-end, user friendly platform for engineers to perform complete manual inspections, as well as tools that allow senior engineers to develop inspection templates and profiles, reducing the requisite thermographic skill level of the operating engineer. Finally, the Sentence software can also offer complete independence of operator decisions by the fully automated "Beep on Defect" detection functionality. The end-to-end automatic inspection system includes sub-systems for defining a panel profile, generating an inspection plan, controlling a robot-arm and capturing thermographic images to detect defects. A statistical model has been built to analyze the entire image, evaluate grey-scale ranges, import sentencing criteria and automatically detect impact damage defects. A full width half maximum algorithm has been used to quantify the flaw sizes. The identified defects are imported into the sentencing engine which then sentences (automatically compares analysis results against acceptance criteria) the inspection by comparing the most significant defect or group of defects against the inspection standards.

  10. Electricity generation from defective tomatoes.

    PubMed

    Shrestha, Namita; Fogg, Alex; Wilder, Joseph; Franco, Daniel; Komisar, Simeon; Gadhamshetty, Venkataramana

    2016-12-01

    The United States faces a significant burden in treating 0.61billionkg of defective tomatoes (culls) every year. We present a proof-of-concept for generating electricity from culled tomatoes in microbial-electrochemical systems (MESs). This study delineates impedance behavior of the culled tomatoes in MESs and compares its impedance spectra with that of soluble substrates (dextrose, acetate, and wastewater). A series of AC and DC diagnostic tests have revealed the superior performance of the culled tomatoes compared to the pure substrates. Cyclic voltammetry results have indicated the active role of indigenous, diffusible redox-active pigments in the culled tomatoes on overall electricity production. Electrochemical impedance spectroscopy results have elucidated the role of peel and seed on the oxidation behavior of the culled tomatoes. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Color vision defects in adrenomyeloneuropathy.

    PubMed Central

    Sack, G H; Raven, M B; Moser, H W

    1989-01-01

    The relationship between abnormal color vision and adrenomyeloneuropathy (AMN) was investigated in 27 AMN patients and 31 age-matched controls by using the Farnsworth-Munsell 100 Hue test. Twelve (44%) of 27 patients showed test scores significantly above normal. The axes of bipolarity determined by the testing differed widely between the patients with abnormal scores, compatible with the notion that different alterations in visual pigment genes occur in different AMN kindreds. These observations confirm our earlier impression that the frequency of abnormal color vision is increased in these kindreds, and it supports our contentions that (1) AMN (and its companion, adrenoleukodystrophy) are very closely linked to the visual pigment loci at Xq28 and (2) this proximity might provide the opportunity to observe contiguous gene defects. PMID:2729274

  12. Convergent molecular defects underpin diverse neurodegenerative diseases.

    PubMed

    Tofaris, George K; Buckley, Noel J

    2018-02-19

    In our ageing population, neurodegenerative disorders carry an enormous personal, societal and economic burden. Although neurodegenerative diseases are often thought of as clinicopathological entities, increasing evidence suggests a considerable overlap in the molecular underpinnings of their pathogenesis. Such overlapping biological processes include the handling of misfolded proteins, defective organelle trafficking, RNA processing, synaptic health and neuroinflammation. Collectively but in different proportions, these biological processes in neurons or non-neuronal cells lead to regionally distinct patterns of neuronal vulnerability and progression of pathology that could explain the disease symptomology. With the advent of patient-derived cellular models and novel genetic manipulation tools, we are now able to interrogate this commonality despite the cellular complexity of the brain in order to develop novel therapeutic strategies to prevent or arrest neurodegeneration. Here, we describe broadly these concepts and their relevance across neurodegenerative diseases. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  13. Closed-Form 3-D Localization for Single Source in Uniform Circular Array with a Center Sensor

    NASA Astrophysics Data System (ADS)

    Bae, Eun-Hyon; Lee, Kyun-Kyung

    A novel closed-form algorithm is presented for estimating the 3-D location (azimuth angle, elevation angle, and range) of a single source in a uniform circular array (UCA) with a center sensor. Based on the centrosymmetry of the UCA and noncircularity of the source, the proposed algorithm decouples and estimates the 2-D direction of arrival (DOA), i.e. azimuth and elevation angles, and then estimates the range of the source. Notwithstanding a low computational complexity, the proposed algorithm provides an estimation performance close to that of the benchmark estimator 3-D MUSIC.

  14. Limb-body wall defect: experience of a reference service of fetal medicine from Southern Brazil.

    PubMed

    Gazolla, Ana C; da Cunha, André C; Telles, Jorge A B; Betat, Rosilene da S; Romano, Mayara A; Marshall, Isabel; Gobatto, Amanda M; de H Bicca, Anna M; Arcolini, Camila P; Dal Pai, Thaís K V; Vieira, Luciane R; Targa, Luciano V; Betineli, Ildo; Zen, Paulo R G; Rosa, Rafael F M

    2014-10-01

    Limb-body wall defect is a rare condition characterized by a combination of large and complex defects of the ventral thorax and abdominal wall with craniofacial and limb anomalies. The aim of this study was to describe the experience of our fetal medicine service, a reference from Southern Brazil, with prenatally diagnosed patients with a limb-body wall defect in a 3 years period. Only patients who fulfilled the criteria suggested by Hunter et al. (2011) were included in the study. Clinical data and results of radiological and cytogenetic evaluation were collected from their medical records. Our sample was composed of 8 patients. Many of their mothers were younger than 25 years (50%) and in their first pregnancy (62.5%). It is noteworthy that one patient was referred due to suspected anencephaly and another due to a twin pregnancy with an embryonic sac. Craniofacial defects were verified in three patients (37.5%), thoracic/abdominal abnormalities in 6 (75%) and limb defects in eight (100%). Congenital heart defects were observed in five patients (62.5%). One of them presented a previously undescribed complex heart defect. The results disclosed that complementary exams, such as MRI and echocardiography, are important to better define the observed defects. Some of them, such as congenital heart defects, may be more common than previously reported. This definition is essential for the proper management of the pregnancy and genetic counseling of the family. The birth of these children must be planned with caution and for the prognosis a long survival possibility, despite unlikely and rare, must be considered. © 2014 Wiley Periodicals, Inc.

  15. Improved Method of Locating Defects in Wiring Insulation

    NASA Technical Reports Server (NTRS)

    Greulich, Owen R.

    2004-01-01

    An improved method of locating small breaches in insulation on electrical wires combines aspects of the prior dielectric withstand voltage (DWV) and time-domain reflectometry (TDR) methods. The method was invented to satisfy a need for reliably and quickly locating insulation defects in spacecraft, aircraft, ships, and other complex systems that contain large amounts of wiring, much of it enclosed in structures that make it difficult to inspect. In the DWV method, one applies a predetermined potential (usually 1.5 kV DC) to the wiring and notes whether the voltage causes any arcing between the wiring and ground. The DWV method does not provide an indication of the location of the defect (unless, in an exceptional case, the arc happens to be visible). In addition, if there is no electrically conductive component at ground potential within about 0.010 in. (approximately equal to 0.254 mm) of the wire at the location of an insulation defect, then the DWV method does not provide an indication of the defect. Moreover, one does not have the option to raise the potential in an effort to increase the detectability of such a defect because doing so can harm previously undamaged insulation. In the TDR method as practiced heretofore, one applies a pulse of electricity having an amplitude of less than 25 V to a wire and measures the round-trip travel time for the reflection of the pulse from a defect. The distance along the wire from the point of application of the pulse to the defect is then calculated as the product of half the round-trip travel time and the characteristic speed of a propagation of an electromagnetic signal in the wire. While the TDR method as practiced heretofore can be used to locate a short or open circuit, it does not ordinarily enable one to locate a small breach in insulation because the pulse voltage is too low to cause arcing and thus too low to induce an impedance discontinuity large enough to generate a measurable reflection. The present improved

  16. Defining defect specifications to optimize photomask production and requalification

    NASA Astrophysics Data System (ADS)

    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.

  17. Ribonucleoprotein complexes in neurologic diseases.

    PubMed

    Ule, Jernej

    2008-10-01

    Ribonucleoprotein (RNP) complexes regulate the tissue-specific RNA processing and transport that increases the coding capacity of our genome and the ability to respond quickly and precisely to the diverse set of signals. This review focuses on three proteins that are part of RNP complexes in most cells of our body: TAR DNA-binding protein (TDP-43), the survival motor neuron protein (SMN), and fragile-X mental retardation protein (FMRP). In particular, the review asks the question why these ubiquitous proteins are primarily associated with defects in specific regions of the central nervous system? To understand this question, it is important to understand the role of genetic and cellular environment in causing the defect in the protein, as well as how the defective protein leads to misregulation of specific target RNAs. Two approaches for comprehensive analysis of defective RNA-protein interactions are presented. The first approach defines the RNA code or the collection of proteins that bind to a certain cis-acting RNA site in order to lead to a predictable outcome. The second approach defines the RNA map or the summary of positions on target RNAs where binding of a particular RNA-binding protein leads to a predictable outcome. As we learn more about the RNA codes and maps that guide the action of the dynamic RNP world in our brain, possibilities for new treatments of neurologic diseases are bound to emerge.

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

    Treesearch

    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...

  19. Laterality Defects Other Than Situs Inversus Totalis in Primary Ciliary Dyskinesia

    PubMed Central

    Davis, Stephanie D.; Ferkol, Thomas; Dell, Sharon D.; Rosenfeld, Margaret; Olivier, Kenneth N.; Sagel, Scott D.; Milla, Carlos; Zariwala, Maimoona A.; Wolf, Whitney; Carson, Johnny L.; Hazucha, Milan J.; Burns, Kimberlie; Robinson, Blair; Knowles, Michael R.; Leigh, Margaret W.

    2014-01-01

    BACKGROUND: Motile cilia dysfunction causes primary ciliary dyskinesia (PCD), situs inversus totalis (SI), and a spectrum of laterality defects, yet the prevalence of laterality defects other than SI in PCD has not been prospectively studied. METHODS: In this prospective study, participants with suspected PCD were referred to our multisite consortium. We measured nasal nitric oxide (nNO) level, examined cilia with electron microscopy, and analyzed PCD-causing gene mutations. Situs was classified as (1) situs solitus (SS), (2) SI, or (3) situs ambiguus (SA), including heterotaxy. Participants with hallmark electron microscopic defects, biallelic gene mutations, or both were considered to have classic PCD. RESULTS: Of 767 participants (median age, 8.1 years, range, 0.1-58 years), classic PCD was defined in 305, including 143 (46.9%), 125 (41.0%), and 37 (12.1%) with SS, SI, and SA, respectively. A spectrum of laterality defects was identified with classic PCD, including 2.6% and 2.3% with SA plus complex or simple cardiac defects, respectively; 4.6% with SA but no cardiac defect; and 2.6% with an isolated possible laterality defect. Participants with SA and classic PCD had a higher prevalence of PCD-associated respiratory symptoms vs SA control participants (year-round wet cough, P < .001; year-round nasal congestion, P = .015; neonatal respiratory distress, P = .009; digital clubbing, P = .021) and lower nNO levels (median, 12 nL/min vs 252 nL/min; P < .001). CONCLUSIONS: At least 12.1% of patients with classic PCD have SA and laterality defects ranging from classic heterotaxy to subtle laterality defects. Specific clinical features of PCD and low nNO levels help to identify PCD in patients with laterality defects. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT00323167; URL: www.clinicaltrials.gov PMID:24577564

  20. Predicting internal white oak (Quercus alba) log defect features using surface defect indicator measurements

    Treesearch

    Ralph E. Thomas

    2012-01-01

    As hardwood trees grow and develop, surface defects such as limb stubs and wounds are overgrown and encapsulated into the tree. Evidence of these defects can remain on the tree's surface for decades and in many instances for the life of the tree. The location and severity of internal defects dictate the quality and value of products that can be obtained from logs...

  1. SEMATECH produces defect-free EUV mask blanks: defect yield and immediate challenges

    NASA Astrophysics Data System (ADS)

    Antohe, Alin O.; Balachandran, Dave; He, Long; Kearney, Patrick; Karumuri, Anil; Goodwin, Frank; Cummings, Kevin

    2015-03-01

    Availability of defect-free reflective mask has been one of the most critical challenges to extreme ultraviolet lithography (EUVL). To mitigate the risk, significant progress has been made on defect detection, pattern shifting, and defect repair. Clearly such mitigation strategies are based on the assumption that defect counts and sizes from incoming mask blanks must be below practical levels depending on mask specifics. The leading industry consensus for early mask product development is that there should be no defects greater than 80 nm in the quality area, 132 mm x 132 mm. In addition less than 10 defects smaller than 80 nm may be mitigable. SEMATECH has been focused on EUV mask blank defect reduction using Veeco Nexus TM IBD platform, the industry standard for mask blank production, and assessing if IBD technology can be evolved to a manufacturing solution. SEMATECH has recently announced a breakthrough reduction of defects in the mask blank deposition process resulting in the production of two defect-free EUV mask blanks at 54 nm inspection sensitivity (SiO2 equivalent). This paper will discuss the dramatic reduction of baseline EUV mask blank defects, review the current deposition process run and compare results with previous process runs. Likely causes of remaining defects will be discussed based on analyses as characterized by their compositions and whether defects are embedded in the multilayer stack or non-embedded.

  2. Classification of maxillectomy defects: a systematic review and criteria necessary for a universal description.

    PubMed

    Bidra, Avinash S; Jacob, Rhonda F; Taylor, Thomas D

    2012-04-01

    Maxillectomy defects are complex and involve a number of anatomic structures. Several maxillectomy defect classifications have been proposed with no universal acceptance among surgeons and prosthodontists. Established criteria for describing the maxillectomy defect are lacking. This systematic review aimed to evaluate classification systems in the available literature, to provide a critical appraisal, and to identify the criteria necessary for a universal description of maxillectomy and midfacial defects. An electronic search of the English language literature between the periods of 1974 and June 2011 was performed by using PubMed, Scopus, and Cochrane databases with predetermined inclusion criteria. Key terms included in the search were maxillectomy classification, maxillary resection classification, maxillary removal classification, maxillary reconstruction classification, midfacial defect classification, and midfacial reconstruction classification. This was supplemented by a manual search of selected journals. After application of predetermined exclusion criteria, the final list of articles was reviewed in-depth to provide a critical appraisal and identify criteria for a universal description of a maxillectomy defect. The electronic database search yielded 261 titles. Systematic application of inclusion and exclusion criteria resulted in identification of 14 maxillectomy and midfacial defect classification systems. From these articles, 6 different criteria were identified as necessary for a universal description of a maxillectomy defect. Multiple deficiencies were noted in each classification system. Though most articles described the superior-inferior extent of the defect, only a small number of articles described the anterior-posterior and medial-lateral extent of the defect. Few articles listed dental status and soft palate involvement when describing maxillectomy defects. No classification system has accurately described the maxillectomy defect, based on

  3. Unsound defect volume in hardwood pallet cants

    Treesearch

    Philip Araman; Matt Winn; Firoz Kabir; Xavier Torcheux; Guillaume Loizeaud

    2003-01-01

    A study was conducted to determine the percentage of unsound defect volume to sound/clear wood in pallet cants at selected sawmills in Virginia and West Virginia. Splits,wane, shake, holes, decay, unsound knots, bark pockets, and mechanical defects were all considered to be unsound. Data were collected from seven Appalachian area sawmills for four hardwood species: red...

  4. Effects of log defects on lumber recovery.

    Treesearch

    James M. Cahill; Vincent S. Cegelka

    1989-01-01

    The impact of log defects on lumber recovery and the accuracy of cubic log scale deductions were evaluated from log scale and product recovery data for more than 3,000 logs. Lumber tally loss was estimated by comparing the lumber yield of sound logs to that of logs containing defects. The data were collected at several product recovery studies; they represent most of...

  5. Nondestructive defect detection in laser optical coatings

    NASA Astrophysics Data System (ADS)

    Marrs, C. D.; Porteus, J. O.; Palmer, J. R.

    1985-03-01

    Defects responsible for laser damage in visible-wavelength mirrors are observed at nondamaging intensities using a new video microscope system. Studies suggest that a defect scattering phenomenon combined with lag characteristics of video cameras makes this possible. Properties of the video-imaged light are described for multilayer dielectric coatings and diamond-turned metals.

  6. 27 CFR 11.32 - Defective products.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Defective products. 11.32 Section 11.32 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT... Beverages Exchanges and Returns for Ordinary and Usual Commercial Reasons § 11.32 Defective products...

  7. Teratology: from science to birth defects prevention.

    PubMed

    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.

  8. Native point defects in GaSb

    SciTech Connect

    Kujala, J.; Segercrantz, N.; Tuomisto, F.

    2014-10-14

    We have applied positron annihilation spectroscopy to study native point defects in Te-doped n-type and nominally undoped p-type GaSb single crystals. The results show that the dominant vacancy defect trapping positrons in bulk GaSb is the gallium monovacancy. The temperature dependence of the average positron lifetime in both p- and n-type GaSb indicates that negative ion type defects with no associated open volume compete with the Ga vacancies. Based on comparison with theoretical predictions, these negative ions are identified as Ga antisites. The concentrations of these negatively charged defects exceed the Ga vacancy concentrations nearly by an order of magnitude.more » We conclude that the Ga antisite is the native defect responsible for p-type conductivity in GaSb single crystals.« less

  9. Native point defects in GaSb

    NASA Astrophysics Data System (ADS)

    Kujala, J.; Segercrantz, N.; Tuomisto, F.; Slotte, J.

    2014-10-01

    We have applied positron annihilation spectroscopy to study native point defects in Te-doped n-type and nominally undoped p-type GaSb single crystals. The results show that the dominant vacancy defect trapping positrons in bulk GaSb is the gallium monovacancy. The temperature dependence of the average positron lifetime in both p- and n-type GaSb indicates that negative ion type defects with no associated open volume compete with the Ga vacancies. Based on comparison with theoretical predictions, these negative ions are identified as Ga antisites. The concentrations of these negatively charged defects exceed the Ga vacancy concentrations nearly by an order of magnitude. We conclude that the Ga antisite is the native defect responsible for p-type conductivity in GaSb single crystals.

  10. Catheter closure of secundum atrial septal defects.

    PubMed

    O'Laughlin, M P

    1997-01-01

    Catheter occlusion of atrial septal defects has its roots in the 1950s, with early devices being implanted during closed-heart surgery without cardiopulmonary bypass. For the past 20 years, various catheter-delivered devices have undergone testing and refinement. Designs have included single- and double-disk prostheses, with a variety of materials, delivery systems, and techniques. In this monograph, the history of atrial septal defect occluders and their evaluation, results, and prognoses will be outlined. The early work of King and Mills has been advanced in the forms of the Rashkind and Lock-USCI Clamshell occluders (USCI; Billerica, Mass), the "buttoned" device (custom made by E.B. Sideris), the Babic atrial septal defect occlusion system (Osypka, GmbH; Grenzach-Wyhlen, Germany), the Das-Angel Wings atrial septal defect occlusion device (Microvena Corporation; White Bear Lake, Minn), and others. The future holds promise for approved devices in the treatment of selected secundum atrial septal defects.

  11. Defective Reduction in Frozen Pie Manufacturing Process

    NASA Astrophysics Data System (ADS)

    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%.

  12. Topological defects in liquid crystals and molecular self-assembly (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Abbott, Nicholas L.

    2017-02-01

    Topological defects in liquid crystals (LCs) have been widely used to organize colloidal dispersions and template polymerizations, leading to a range of elastomers and gels with complex mechanical and optical properties. However, little is understood about molecular-level assembly processes within defects. This presentation will describe an experimental study that reveals that nanoscopic environments defined by LC topological defects can selectively trigger processes of molecular self-assembly. By using fluorescence microscopy, cryogenic transmission electron microscopy and super-resolution optical microscopy, key signatures of molecular self-assembly of amphiphilic molecules in topological defects are observed - including cooperativity, reversibility, and controlled growth of the molecular assemblies. By using polymerizable amphiphiles, we also demonstrate preservation of molecular assemblies templated by defects, including nanoscopic "o-rings" synthesized from "Saturn-ring" disclinations. Our results reveal that topological defects in LCs are a versatile class of three-dimensional, dynamic and reconfigurable templates that can direct processes of molecular self-assembly in a manner that is strongly analogous to other classes of macromolecular templates (e.g., polymer—surfactant complexes). Opportunities for the design of exquisitely responsive soft materials will be discussed using bacterial endotoxin as an example.

  13. Electron-pinned defect-dipoles for high-performance colossal permittivity materials

    NASA Astrophysics Data System (ADS)

    Hu, Wanbiao; Liu, Yun; Withers, Ray L.; Frankcombe, Terry J.; Norén, Lasse; Snashall, Amanda; Kitchin, Melanie; Smith, Paul; Gong, Bill; Chen, Hua; Schiemer, Jason; Brink, Frank; Wong-Leung, Jennifer

    2013-09-01

    The immense potential of colossal permittivity (CP) materials for use in modern microelectronics as well as for high-energy-density storage applications has propelled much recent research and development. Despite the discovery of several new classes of CP materials, the development of such materials with the required high performance is still a highly challenging task. Here, we propose a new electron-pinned, defect-dipole route to ideal CP behaviour, where hopping electrons are localized by designated lattice defect states to generate giant defect-dipoles and result in high-performance CP materials. We present a concrete example, (Nb+In) co-doped TiO2 rutile, that exhibits a largely temperature- and frequency-independent colossal permittivity (> 104) as well as a low dielectric loss (mostly < 0.05) over a very broad temperature range from 80 to 450 K. A systematic defect analysis coupled with density functional theory modelling suggests that ‘triangular’ In23+VO••Ti3+ and ‘diamond’ shaped Nb25+Ti3+ATi (A  =  Ti3+/In3+/Ti4+) defect complexes are strongly correlated, giving rise to large defect-dipole clusters containing highly localized electrons that are together responsible for the excellent CP properties observed in co-doped TiO2. This combined experimental and theoretical work opens up a promising feasible route to the systematic development of new high-performance CP materials via defect engineering.

  14. Electron-pinned defect-dipoles for high-performance colossal permittivity materials.

    PubMed

    Hu, Wanbiao; Liu, Yun; Withers, Ray L; Frankcombe, Terry J; Norén, Lasse; Snashall, Amanda; Kitchin, Melanie; Smith, Paul; Gong, Bill; Chen, Hua; Schiemer, Jason; Brink, Frank; Wong-Leung, Jennifer

    2013-09-01

    The immense potential of colossal permittivity (CP) materials for use in modern microelectronics as well as for high-energy-density storage applications has propelled much recent research and development. Despite the discovery of several new classes of CP materials, the development of such materials with the required high performance is still a highly challenging task. Here, we propose a new electron-pinned, defect-dipole route to ideal CP behaviour, where hopping electrons are localized by designated lattice defect states to generate giant defect-dipoles and result in high-performance CP materials. We present a concrete example, (Nb+In) co-doped TiO₂ rutile, that exhibits a largely temperature- and frequency-independent colossal permittivity (> 10(4)) as well as a low dielectric loss (mostly < 0.05) over a very broad temperature range from 80 to 450 K. A systematic defect analysis coupled with density functional theory modelling suggests that 'triangular' In₂(3+)Vo(••)Ti(3+) and 'diamond' shaped Nb₂(5+)Ti(3+)A(Ti) (A = Ti(3+)/In(3+)/Ti(4+)) defect complexes are strongly correlated, giving rise to large defect-dipole clusters containing highly localized electrons that are together responsible for the excellent CP properties observed in co-doped TiO₂. This combined experimental and theoretical work opens up a promising feasible route to the systematic development of new high-performance CP materials via defect engineering.

  15. Modeling Anterior Development in Mice: Diet as Modulator of Risk for Neural Tube Defects

    PubMed Central

    Kappen, Claudia

    2014-01-01

    Head morphogenesis is a complex process that is controlled by multiple signaling centers. The most common defects of cranial development are craniofacial defects, such as cleft lip and cleft palate, and neural tube defects, such as anencephaly and encephalocoele in humans. More than 400 genes that contribute to proper neural tube closure have been identified in experimental animals, but only very few causative gene mutations have been identified in humans, supporting the notion that environmental influences are critical. The intrauterine environment is influenced by maternal nutrition, and hence, maternal diet can modulate the risk for cranial and neural tube defects. This article reviews recent progress toward a better understanding of nutrients during pregnancy, with particular focus on mouse models for defective neural tube closure. At least four major patterns of nutrient responses are apparent, suggesting that multiple pathways are involved in the response, and likely in the underlying pathogenesis of the defects. Folic acid has been the most widely studied nutrient, and the diverse responses of the mouse models to folic acid supplementation indicate that folic acid is not universally beneficial, but that the effect is dependent on genetic configuration. If this is the case for other nutrients as well, efforts to prevent neural tube defects with nutritional supplementation may need to become more specifically targeted than previously appreciated. Mouse models are indispensable for a better understanding of nutrient–gene interactions in normal pregnancies, as well as in those affected by metabolic diseases, such as diabetes and obesity. PMID:24124024

  16. Optical method and apparatus for detection of surface and near-subsurface defects in dense ceramics

    DOEpatents

    Ellingson, W.A.; Brada, M.P.

    1995-06-20

    A laser is used in a non-destructive manner to detect surface and near-subsurface defects in dense ceramics and particularly in ceramic bodies with complex shapes such as ceramic bearings, turbine blades, races, and the like. The laser`s wavelength is selected based upon the composition of the ceramic sample and the laser can be directed on the sample while the sample is static or in dynamic rotate or translate motion. Light is scattered off surface and subsurface defects using a preselected polarization. The change in polarization angle is used to select the depth and characteristics of surface/subsurface defects. The scattered light is detected by an optical train consisting of a charge coupled device (CCD), or vidicon, television camera which, in turn, is coupled to a video monitor and a computer for digitizing the image. An analyzing polarizer in the optical train allows scattered light at a given polarization angle to be observed for enhancing sensitivity to either surface or near-subsurface defects. Application of digital image processing allows subtraction of digitized images in near real-time providing enhanced sensitivity to subsurface defects. Storing known ``feature masks`` of identified defects in the computer and comparing the detected scatter pattern (Fourier images) with the stored feature masks allows for automatic classification of detected defects. 29 figs.

  17. Optical method and apparatus for detection of surface and near-subsurface defects in dense ceramics

    DOEpatents

    Ellingson, William A.; Brada, Mark P.

    1995-01-01

    A laser is used in a non-destructive manner to detect surface and near-subsurface defects in dense ceramics and particularly in ceramic bodies with complex shapes such as ceramic bearings, turbine blades, races, and the like. The laser's wavelength is selected based upon the composition of the ceramic sample and the laser can be directed on the sample while the sample is static or in dynamic rotate or translate motion. Light is scattered off surface and subsurface defects using a preselected polarization. The change in polarization angle is used to select the depth and characteristics of surface/subsurface defects. The scattered light is detected by an optical train consisting of a charge coupled device (CCD), or vidicon, television camera which, in turn, is coupled to a video monitor and a computer for digitizing the image. An analyzing polarizer in the optical train allows scattered light at a given polarization angle to be observed for enhancing sensitivity to either surface or near-subsurface defects. Application of digital image processing allows subtraction of digitized images in near real-time providing enhanced sensitivity to subsurface defects. Storing known "feature masks" of identified defects in the computer and comparing the detected scatter pattern (Fourier images) with the stored feature masks allows for automatic classification of detected defects.

  18. Point defects at the ice (0001) surface

    PubMed Central

    Watkins, Matthew; VandeVondele, Joost; Slater, Ben

    2010-01-01

    Using density functional theory we investigate whether intrinsic defects in ice surface segregate. We predict that hydronium, hydroxide, and the Bjerrum L- and D-defects are all more stable at the surface. However, the energetic cost to create a D-defect at the surface and migrate it into the bulk crystal is smaller than its bulk formation energy. Absolute and relative segregation energies are sensitive to the surface structure of ice, especially the spatial distribution of protons associated with dangling hydrogen bonds. It is found that the basal plane surface of hexagonal ice increases the bulk concentration of Bjerrum defects, strongly favoring D-defects over L-defects. Dangling protons associated with undercoordinated water molecules are preferentially injected into the crystal bulk as Bjerrum D-defects, leading to a surface dipole that attracts hydronium ions. Aside from the disparity in segregation energies for the Bjerrum defects, we find the interactions between defect species to be very finely balanced; surface segregation energies for hydronium and hydroxide species and trapping energies of these ionic species with Bjerrum defects are equal within the accuracy of our calculations. The mobility of the ionic hydronium and hydroxide species is greatly reduced at the surface in comparison to the bulk due to surface sites with high trapping affinities. We suggest that, in pure ice samples, the surface of ice will have an acidic character due to the presence of hydronium ions. This may be important in understanding the reactivity of ice particulates in the upper atmosphere and at the boundary layer. PMID:20615938

  19. Wafer plane inspection for advanced reticle defects

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

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

    2013-01-01

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

  1. A Proposed Defect Tracking Model for Classifying the Inserted Defect Reports to Enhance Software Quality Control

    PubMed Central

    Khedr, Ayman E.; Sayed, Mostafa

    2013-01-01

    CONFLICT OF INTEREST: 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. PMID:24039334

  2. Formation and local heating effects on the vibrational properties of H2* defects in crystalline silicon

    NASA Astrophysics Data System (ADS)

    Vendamani, V. S.; Pathak, A. P.; Kanjilal, D.; Rao, S. V. S. Nageswara

    2018-04-01

    We report a successful formation of Si-H related complexes under low temperature (LT) proton implantation. H2* defect is one of the Si-H related defects, which is stable at around 600 K. The absorption line of H2* defect is around 1830 cm-1 and has been investigated by Fourier transform infrared spectroscopy (FTIR). The intensity variations in the absorption spectrum has been observed for samples implanted at 1 µA and 8 µA beam currents. It is found that, the formation of H2* defect tends towards saturation level at higher implanted fluencies. This observation might be the effect of ion induced annealing during proton implantation. In addition, Elastic recoil detection analysis (ERDA) has been performed to find out the concentration and desorption of hydrogen in proton implanted Si samples. In conclusion, this work demonstrates the importance of H passivation on the device stability/deterioration performance.

  3. Research on metallic material defect detection based on bionic sensing of human visual properties

    NASA Astrophysics Data System (ADS)

    Zhang, Pei Jiang; Cheng, Tao

    2018-05-01

    Due to the fact that human visual system can quickly lock the areas of interest in complex natural environment and focus on it, this paper proposes an eye-based visual attention mechanism by simulating human visual imaging features based on human visual attention mechanism Bionic Sensing Visual Inspection Model Method to Detect Defects of Metallic Materials in the Mechanical Field. First of all, according to the biologically visually significant low-level features, the mark of defect experience marking is used as the intermediate feature of simulated visual perception. Afterwards, SVM method was used to train the advanced features of visual defects of metal material. According to the weight of each party, the biometrics detection model of metal material defect, which simulates human visual characteristics, is obtained.

  4. International adoption of children with birth defects: current knowledge and areas for further research.

    PubMed

    Cochran, Meagan E; Nelson, Katherine R; Robin, Nathaniel H

    2014-12-01

    To summarize the existing literature on the international adoption of children with birth defects and identify areas for further research. International adoption brings thousands of children to the United States each year, and children with birth defects are overrepresented in this population. Studies have demonstrated disparities in the health of children adopted from different countries as well as the complexity of medical care needed after adoption. Although the health of children involved in international adoption has been well studied, there is a lack of information about the experiences of the adoptive parents of children with birth defects. We discuss a pilot study conducted on adoptive parents of children with a specific birth defect, orofacial clefting, and discuss areas for future research.

  5. Tuning of defects in ZnO nanorod arrays used in bulk heterojunction solar cells

    PubMed Central

    2012-01-01

    With particular focus on bulk heterojunction solar cells incorporating ZnO nanorods, we study how different annealing environments (air or Zn environment) and temperatures impact on the photoluminescence response. Our work gives new insight into the complex defect landscape in ZnO, and it also shows how the different defect types can be manipulated. We have determined the emission wavelengths for the two main defects which make up the visible band, the oxygen vacancy emission wavelength at approximately 530 nm and the zinc vacancy emission wavelength at approximately 630 nm. The precise nature of the defect landscape in the bulk of the nanorods is found to be unimportant to photovoltaic cell performance although the surface structure is more critical. Annealing of the nanorods is optimum at 300°C as this is a sufficiently high temperature to decompose Zn(OH)2 formed at the surface of the nanorods during electrodeposition and sufficiently low to prevent ITO degradation. PMID:23186280

  6. Synchrotron X-ray CT characterization of titanium parts fabricated by additive manufacturing. Part II. Defects.

    PubMed

    Scarlett, Nicola Vivienne Yorke; Tyson, Peter; Fraser, Darren; Mayo, Sheridan; Maksimenko, Anton

    2016-07-01

    Synchrotron X-ray tomography (SXRT) has been applied to the study of defects within three-dimensional printed titanium parts. These parts were made using the Arcam EBM(®) (electron beam melting) process which uses powdered titanium alloy, Ti64 (Ti alloy with approximately 6%Al and 4%V) as the feed and an electron beam for the sintering/welding. The experiment was conducted on the Imaging and Medical Beamline of the Australian Synchrotron. The samples represent a selection of complex shapes with a variety of internal morphologies. Inspection via SXRT has revealed a number of defects which may not otherwise have been seen. The location and nature of such defects combined with detailed knowledge of the process conditions can contribute to understanding the interplay between design and manufacturing strategy. This fundamental understanding may subsequently be incorporated into process modelling, prediction of properties and the development of robust methodologies for the production of defect-free parts.

  7. Defect-induced magnetism in cobalt-doped ZnO epilayers

    NASA Astrophysics Data System (ADS)

    Ciatto, G.; Di Trolio, A.; Fonda, E.; Alippi, P.; Polimeni, A.; Capizzi, M.; Varvaro, G.; Bonapasta, A. Amore

    2014-02-01

    We used a synergic Co-edge X-ray absorption spectroscopy (XAS) and density functional theory calculations approach to perform a study of defects which could account for the room temperature ferromagnetism of ZnCoO, an oxide of great potential interest in semiconductor spintronics. Our results suggest that a key role is played by specific defect complexes in which O vacancies are located close to the Co atoms. Extended defects such as Co clusters have a marginal function, although we observe their formation at the epilayer surface under certain growth conditions. We also show preliminary results of the study of hydrogen-induced defects in ZnCoO epilayers deliberately hydrogen irradiated via a Kaufman source. Hydrogen was in fact predicted to mediate a ferromagnetic spin-spin interaction between neighboring magnetic impurities.

  8. Defect chaos of oscillating hexagons in rotating convection

    PubMed

    Echebarria; Riecke

    2000-05-22

    Using coupled Ginzburg-Landau equations, the dynamics of hexagonal patterns with broken chiral symmetry are investigated, as they appear in rotating non-Boussinesq or surface-tension-driven convection. We find that close to the secondary Hopf bifurcation to oscillating hexagons the dynamics are well described by a single complex Ginzburg-Landau equation (CGLE) coupled to the phases of the hexagonal pattern. At the band center these equations reduce to the usual CGLE and the system exhibits defect chaos. Away from the band center a transition to a frozen vortex state is found.

  9. Investigation of membranous ventricular septal defect complicated with tricuspid regurgitation in ventricular septal defect occlusion

    PubMed Central

    LIU, SHU-PING; LI, LI; YAO, KE-CHUN; WANG, NA; WANG, JIAN-CHANG

    2013-01-01

    This study aimed to explore the mechanism of membranous ventricular septal defect complicated with tricuspid regurgitation and the significance of ventricular septal defect occlusion by echocardiography. A total of 43 patients with membranous ventricular septal defect complicated with tricuspid regurgitation were observed by echocardiography and the changes in length, area and volume of tricuspid regurgitation prior to and following ventricular septal defect occlusion were measured. There were four different mechanisms of membranous ventricular septal defect complicated with tricuspid regurgitation. The various indices of tricuspid regurgitation volume were significantly reduced following occlusion. Ventricular septal defect occlusion significantly reduces tricuspid regurgitation volume complicated with membranous ventricular septal defect and echocardiography is an ideal method to detect these changes. PMID:23404058

  10. Aspects of defects in 3d-3d correspondence

    DOE PAGES

    Gang, Dongmin; Kim, Nakwoo; Romo, Mauricio; ...

    2016-10-12

    In this paper we study supersymmetric co-dimension 2 and 4 defects in the compactification of the 6d (2, 0) theory of type A N-1 on a 3-manifold M . The so-called 3d-3d correspondence is a relation between complexified Chern-Simons theory (with gauge group SL(N,C) ) on M and a 3d N=2 theory T N [M ]. We study this correspondence in the presence of supersymmetric defects, which are knots/links inside the 3-manifold. Our study employs a number of different methods: state-integral models for complex Chern-Simons theory, cluster algebra techniques, domain wall theory T [SU(N )], 5d N=2 SYM, and alsomore » supergravity analysis through holography. These methods are complementary and we find agreement between them. In some cases the results lead to highly non-trivial predictions on the partition function. Our discussion includes a general expression for the cluster partition function, which can be used to compute in the presence of maximal and certain class of non-maximal punctures when N > 2. We also highlight the non-Abelian description of the 3d N=2 T N [M ] theory with defect included, when such a description is available. This paper is a companion to our shorter paper, which summarizes our main results.« less

  11. Topological Defects in a Living Nematic Ensnare Swimming Bacteria

    NASA Astrophysics Data System (ADS)

    Genkin, Mikhail M.; Sokolov, Andrey; Lavrentovich, Oleg D.; Aranson, Igor S.

    2017-01-01

    Active matter exemplified by suspensions of motile bacteria or synthetic self-propelled particles exhibits a remarkable propensity to self-organization and collective motion. The local input of energy and simple particle interactions often lead to complex emergent behavior manifested by the formation of macroscopic vortices and coherent structures with long-range order. A realization of an active system has been conceived by combining swimming bacteria and a lyotropic liquid crystal. Here, by coupling the well-established and validated model of nematic liquid crystals with the bacterial dynamics, we develop a computational model describing intricate properties of such a living nematic. In faithful agreement with the experiment, the model reproduces the onset of periodic undulation of the director and consequent proliferation of topological defects with the increase in bacterial concentration. It yields a testable prediction on the accumulation of bacteria in the cores of +1 /2 topological defects and depletion of bacteria in the cores of -1 /2 defects. Our dedicated experiment on motile bacteria suspended in a freestanding liquid crystalline film fully confirms this prediction. Our findings suggest novel approaches for trapping and transport of bacteria and synthetic swimmers in anisotropic liquids and extend a scope of tools to control and manipulate microscopic objects in active matter.

  12. A review of craniofacial disorders caused by spliceosomal defects.

    PubMed

    Lehalle, D; Wieczorek, D; Zechi-Ceide, R M; Passos-Bueno, M R; Lyonnet, S; Amiel, J; Gordon, C T

    2015-11-01

    The spliceosome is a large ribonucleoprotein complex that removes introns from pre-mRNA transcripts. Mutations in EFTUD2, encoding a component of the major spliceosome, have recently been identified as the cause of mandibulofacial dysostosis, Guion-Almeida type (MFDGA), characterized by mandibulofacial dysostosis, microcephaly, external ear malformations and intellectual disability. Mutations in several other genes involved in spliceosomal function or linked aspects of mRNA processing have also recently been identified in human disorders with specific craniofacial malformations: SF3B4 in Nager syndrome, an acrofacial dysostosis (AFD); SNRPB in cerebrocostomandibular syndrome, characterized by Robin sequence and rib defects; EIF4A3 in the AFD Richieri-Costa-Pereira syndrome, characterized by Robin sequence, median mandibular cleft and limb defects; and TXNL4A in Burn-McKeown syndrome, involving specific craniofacial dysmorphisms. Here, we review phenotypic and molecular aspects of these syndromes. Given the apparent sensitivity of craniofacial development to defects in mRNA processing, it is possible that mutations in other proteins involved in spliceosomal function will emerge in the future as causative for related human disorders. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Inspecting rapidly moving surfaces for small defects using CNN cameras

    NASA Astrophysics Data System (ADS)

    Blug, Andreas; Carl, Daniel; Höfler, Heinrich

    2013-04-01

    A continuous increase in production speed and manufacturing precision raises a demand for the automated detection of small image features on rapidly moving surfaces. An example are wire drawing processes where kilometers of cylindrical metal surfaces moving with 10 m/s have to be inspected for defects such as scratches, dents, grooves, or chatter marks with a lateral size of 100 μm in real time. Up to now, complex eddy current systems are used for quality control instead of line cameras, because the ratio between lateral feature size and surface speed is limited by the data transport between camera and computer. This bottleneck is avoided by "cellular neural network" (CNN) cameras which enable image processing directly on the camera chip. This article reports results achieved with a demonstrator based on this novel analogue camera - computer system. The results show that computational speed and accuracy of the analogue computer system are sufficient to detect and discriminate the different types of defects. Area images with 176 x 144 pixels are acquired and evaluated in real time with frame rates of 4 to 10 kHz - depending on the number of defects to be detected. These frame rates correspond to equivalent line rates on line cameras between 360 and 880 kHz, a number far beyond the available features. Using the relation between lateral feature size and surface speed as a figure of merit, the CNN based system outperforms conventional image processing systems by an order of magnitude.

  14. Studying post-etching silicon crystal defects on 300mm wafer by automatic defect review AFM

    NASA Astrophysics Data System (ADS)

    Zandiatashbar, Ardavan; Taylor, Patrick A.; Kim, Byong; Yoo, Young-kook; Lee, Keibock; Jo, Ahjin; Lee, Ju Suk; Cho, Sang-Joon; Park, Sang-il

    2016-03-01

    Single crystal silicon wafers are the fundamental elements of semiconductor manufacturing industry. The wafers produced by Czochralski (CZ) process are very high quality single crystalline materials with known defects that are formed during the crystal growth or modified by further processing. While defects can be unfavorable for yield for some manufactured electrical devices, a group of defects like oxide precipitates can have both positive and negative impacts on the final device. The spatial distribution of these defects may be found by scattering techniques. However, due to limitations of scattering (i.e. light wavelength), many crystal defects are either poorly classified or not detected. Therefore a high throughput and accurate characterization of their shape and dimension is essential for reviewing the defects and proper classification. While scanning electron microscopy (SEM) can provide high resolution twodimensional images, atomic force microscopy (AFM) is essential for obtaining three-dimensional information of the defects of interest (DOI) as it is known to provide the highest vertical resolution among all techniques [1]. However AFM's low throughput, limited tip life, and laborious efforts for locating the DOI have been the limitations of this technique for defect review for 300 mm wafers. To address these limitations of AFM, automatic defect review AFM has been introduced recently [2], and is utilized in this work for studying DOI on 300 mm silicon wafer. In this work, we carefully etched a 300 mm silicon wafer with a gaseous acid in a reducing atmosphere at a temperature and for a sufficient duration to decorate and grow the crystal defects to a size capable of being detected as light scattering defects [3]. The etched defects form a shallow structure and their distribution and relative size are inspected by laser light scattering (LLS). However, several groups of defects couldn't be properly sized by the LLS due to the very shallow depth and low

  15. Complexity Survey.

    ERIC Educational Resources Information Center

    Gordon, Sandra L.; Anderson, Beth C.

    To determine whether consensus existed among teachers about the complexity of common classroom materials, a survey was administered to 66 pre-service and in-service kindergarten and prekindergarten teachers. Participants were asked to rate 14 common classroom materials as simple, complex, or super-complex. Simple materials have one obvious part,…

  16. Pressure-Photoluminescence Study of the Zn Vacancy and Donor Zn-Vacancy Complexes in ZnSe

    NASA Astrophysics Data System (ADS)

    Iota, V.; Weinstein, B. A.

    1997-03-01

    We report photoluminescence (PL) results to 65kbar (at 8K) on n-type electron irradiated ZnSe containing high densities of isolated Zn vacancies (V_Zn) and donor-V_Zn complexes (A-centers).^1 Isotropic pressure is applied using a diamond-anvil cell with He medium, and laser excitations above and below the ZnSe bandgap (2.82eV) are employed. The 1 atm. spectra exhibit excitonic lines, shallow donor-acceptor pair (DAP) peaks, and two broad bands due to DAP transitions between shallow donors and deep acceptor states at A-centers (2.07eV) or V_Zn (1.72eV). At all pressures, these broad bands are prominent only for sub-gap excitation, which results in: i) A-center PL at energies above the laser line, and ii) strong enhancement of the first LO-replica in the shallow DAP series compared to 3.41eV UV excitation. This suggests that sub-gap excitation produces long-lived metastable acceptor states. The broad PL bands shift to higher energy with pressure faster than the ZnSe direct gap, indicating that compression causes the A-center and V_Zn deep acceptor levels to approach the hole continuum. This behavior is similar to that found by our group for P and As deep acceptor levels in ZnSe, supporting the view that deep substitutional defects often resemble the limiting case of a vacancy. ^1D. Y. Jeon, H. P. Gislason, G. D. Watkins Phys. Rev. B 48, 7872 (1993); we thank G. D. Watkins for providing the samples. (figures)

  17. Nitrogen vacancy complexes in nitrogen irradiated metals

    SciTech Connect

    Veen, A. van; Westerduin, K.T.; Schut, H.

    1996-12-31

    Gas desorption and positron annihilation techniques have been employed to study the evolution of nitrogen associated defects in nitrogen irradiated metals: Fe, Ni, Mo and W. Nitrogen in these metals has a rather high affinity to vacancy type defects. The results obtained for low irradiation dose show that substitutional nitrogen (NV; with V = vacancy) is formed. The nitrogen vacancy complex dissociates at temperatures ranging from 350 K for Ni to 900 K for Mo and 1,100 K for W. At high doses defects are formed which can be characterized as nitrogen saturated vacancy clusters. These defect, as observed bymore » helium probing, disappear during annealing for nickel at 800 K, and for Mo at 1,100 K. The direct observation of the desorbing nitrogen for nickel and molybdenum reveals a very fast desorption transient at the dissociation temperature of the clusters. This is the characteristic desorption transient of a small nitride cluster, e.g., by shrinkage with constant rate. For iron the nitrogen desorption is more complicated because of a general background that continuously rises with temperature. With the positron beam technique depth information was obtained for defects in iron and the defect character could be established with the help of the information provided on annihilation with conduction and core electrons of the defect trapped positrons.« less

  18. Modeling of Powder Bed Manufacturing Defects

    NASA Astrophysics Data System (ADS)

    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.

  19. Defect Chemistry of Oxides for Energy Applications.

    PubMed

    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.

  20. Platelet rich fibrin in jaw defects

    NASA Astrophysics Data System (ADS)

    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.

  1. Defect identification for the As Ga family

    NASA Astrophysics Data System (ADS)

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

    2003-12-01

    The AsGa 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 AsGa-related defects. We confirm the identification of the isolated AsGa and show that the {AsGa-X2} defect must be identified with the nearest-neighbor antistructure pair rather than with the {AsGa-VAs} pair. For the {AsGa-X1} defect a distant antistructure pair is a likely candidate. For the EL2, the most important member of the AsGa family, we have not found a conclusive defect model. The recent ODENDOR data are similar to those of the distant orthorhombic {AsGa-VGa} pair, which, however is a triple acceptor and not a donor.

  2. Defect imaging in composite structures

    NASA Astrophysics Data System (ADS)

    Fromme, Paul; Endrizzi, Marco; Olivo, Alessandro

    2018-04-01

    Carbon fiber laminate composites offer advantages including a good strength to weight ratio for aerospace structures. However, manufacturing imperfections and impact during the operation and servicing of the aircraft can lead to barely visible and difficult to detect damage. Incorrect ply lay-up during the manufacturing process can result in fiber misalignment or in-plane and out-of-plane waviness. Impact, such as bird strike, during the service life can lead to delamination and cracking, reducing the load carrying capacity of the structure. Both ultrasonic and X-ray techniques have a good track record for the nondestructive testing of composite structures; for the latter, phase-based approaches provide additional advantages due to their enhanced sensitivity. Bulk and guided ultrasonic waves propagating in the composite panel were employed for defect imaging. Ultrasonic immersion C-scans of a composite panel with barely visible impact damage were taken to characterize the size and shape of damage (delamination). The first antisymmetric A0 Lamb wave mode was excited experimentally using piezoelectric transducers and measured using a laser vibrometer. X-ray phase-contrast and dark field imaging, implemented through the edge-illumination (EI) approach, were used for the detailed visualization of the damages in the composite material. The Edge-illumination approach is multi-modal and provides three representations of the sample: absorption, differential phase and dark-field. The latter is of particular interest to detect cracks and voids of dimensions that are smaller than the actual spatial resolution of the imaging system. Application examples for carbon fiber composite plates with barely visible impact damage are shown.

  3. Advanced repair solution of clear defects on HTPSM by using nanomachining tool

    NASA Astrophysics Data System (ADS)

    Lee, Hyemi; Kim, Munsik; Jung, Hoyong; Kim, Sangpyo; Yim, Donggyu

    2015-10-01

    As the mask specifications become tighter for low k1 lithography, more aggressive repair accuracy is required below sub 20nm tech. node. To meet tight defect specifications, many maskshops select effective repair tools according to defect types. Normally, pattern defects are repaired by the e-beam repair tool and soft defects such as particles are repaired by the nanomachining tool. It is difficult for an e-beam repair tool to remove particle defects because it uses chemical reaction between gas and electron, and a nanomachining tool, which uses physical reaction between a nano-tip and defects, cannot be applied for repairing clear defects. Generally, film deposition process is widely used for repairing clear defects. However, the deposited film has weak cleaning durability, so it is easily removed by accumulated cleaning process. Although the deposited film is strongly attached on MoSiN(or Qz) film, the adhesive strength between deposited Cr film and MoSiN(or Qz) film becomes weaker and weaker by the accumulated energy when masks are exposed in a scanner tool due to the different coefficient of thermal expansion of each materials. Therefore, whenever a re-pellicle process is needed to a mask, all deposited repair points have to be confirmed whether those deposition film are damaged or not. And if a deposition point is damaged, repair process is needed again. This process causes longer and more complex process. In this paper, the basic theory and the principle are introduced to recover clear defects by using nanomachining tool, and the evaluated results are reviewed at dense line (L/S) patterns and contact hole (C/H) patterns. Also, the results using a nanomachining were compared with those using an e-beam repair tool, including the cleaning durability evaluated by the accumulated cleaning process. Besides, we discuss the phase shift issue and the solution about the image placement error caused by phase error.

  4. Communication complexity and information complexity

    NASA Astrophysics Data System (ADS)

    Pankratov, Denis

    Information complexity enables the use of information-theoretic tools in communication complexity theory. Prior to the results presented in this thesis, information complexity was mainly used for proving lower bounds and direct-sum theorems in the setting of communication complexity. We present three results that demonstrate new connections between information complexity and communication complexity. In the first contribution we thoroughly study the information complexity of the smallest nontrivial two-party function: the AND function. While computing the communication complexity of AND is trivial, computing its exact information complexity presents a major technical challenge. In overcoming this challenge, we reveal that information complexity gives rise to rich geometrical structures. Our analysis of information complexity relies on new analytic techniques and new characterizations of communication protocols. We also uncover a connection of information complexity to the theory of elliptic partial differential equations. Once we compute the exact information complexity of AND, we can compute exact communication complexity of several related functions on n-bit inputs with some additional technical work. Previous combinatorial and algebraic techniques could only prove bounds of the form theta( n). Interestingly, this level of precision is typical in the area of information theory, so our result demonstrates that this meta-property of precise bounds carries over to information complexity and in certain cases even to communication complexity. Our result does not only strengthen the lower bound on communication complexity of disjointness by making it more exact, but it also shows that information complexity provides the exact upper bound on communication complexity. In fact, this result is more general and applies to a whole class of communication problems. In the second contribution, we use self-reduction methods to prove strong lower bounds on the information

  5. Modelling NDE pulse-echo inspection of misorientated planar rough defects using an elastic finite element method

    SciTech Connect

    Pettit, J. R.; Lowe, M. J. S.; Walker, A. E.

    2015-03-31

    Pulse-echo ultrasonic NDE examination of large pressure vessel forgings is a design and construction code requirement in the power generation industry. Such inspections aim to size and characterise potential defects that may have formed during the forging process. Typically these defects have a range of orientations and surface roughnesses which can greatly affect ultrasonic wave scattering behaviour. Ultrasonic modelling techniques can provide insight into defect response and therefore aid in characterisation. However, analytical approaches to solving these scattering problems can become inaccurate, especially when applied to increasingly complex defect geometries. To overcome these limitations a elastic Finite Element (FE) methodmore » has been developed to simulate pulse-echo inspections of embedded planar defects. The FE model comprises a significantly reduced spatial domain allowing for a Monte-Carlo based approach to consider multiple realisations of defect orientation and surface roughness. The results confirm that defects aligned perpendicular to the path of beam propagation attenuate ultrasonic signals according to the level of surface roughness. However, for defects orientated away from this plane, surface roughness can increase the magnitude of the scattered component propagating back along the path of the incident beam. This study therefore highlights instances where defect roughness increases the magnitude of ultrasonic scattered signals, as opposed to attenuation which is more often assumed.« less

  6. Modelling NDE pulse-echo inspection of misorientated planar rough defects using an elastic finite element method

    NASA Astrophysics Data System (ADS)

    Pettit, J. R.; Walker, A. E.; Lowe, M. J. S.

    2015-03-01

    Pulse-echo ultrasonic NDE examination of large pressure vessel forgings is a design and construction code requirement in the power generation industry. Such inspections aim to size and characterise potential defects that may have formed during the forging process. Typically these defects have a range of orientations and surface roughnesses which can greatly affect ultrasonic wave scattering behaviour. Ultrasonic modelling techniques can provide insight into defect response and therefore aid in characterisation. However, analytical approaches to solving these scattering problems can become inaccurate, especially when applied to increasingly complex defect geometries. To overcome these limitations a elastic Finite Element (FE) method has been developed to simulate pulse-echo inspections of embedded planar defects. The FE model comprises a significantly reduced spatial domain allowing for a Monte-Carlo based approach to consider multiple realisations of defect orientation and surface roughness. The results confirm that defects aligned perpendicular to the path of beam propagation attenuate ultrasonic signals according to the level of surface roughness. However, for defects orientated away from this plane, surface roughness can increase the magnitude of the scattered component propagating back along the path of the incident beam. This study therefore highlights instances where defect roughness increases the magnitude of ultrasonic scattered signals, as opposed to attenuation which is more often assumed.

  7. Application of RNAMlet to surface defect identification of steels

    NASA Astrophysics Data System (ADS)

    Xu, Ke; Xu, Yang; Zhou, Peng; Wang, Lei

    2018-06-01

    As three main production lines of steels, continuous casting slabs, hot rolled steel plates and cold rolled steel strips have different surface appearances and are produced at different speeds of their production lines. Therefore, the algorithms for the surface defect identifications of the three steel products have different requirements for real-time and anti-interference. The existing algorithms cannot be adaptively applied to surface defect identification of the three steel products. A new method of adaptive multi-scale geometric analysis named RNAMlet was proposed. The idea of RNAMlet came from the non-symmetry anti-packing pattern representation model (NAM). The image is decomposed into a set of rectangular blocks asymmetrically according to gray value changes of image pixels. Then two-dimensional Haar wavelet transform is applied to all blocks. If the image background is complex, the number of blocks is large, and more details of the image are utilized. If the image background is simple, the number of blocks is small, and less computation time is needed. RNAMlet was tested with image samples of the three steel products, and compared with three classical methods of multi-scale geometric analysis, including Contourlet, Shearlet and Tetrolet. For the image samples with complicated backgrounds, such as continuous casting slabs and hot rolled steel plates, the defect identification rate obtained by RNAMlet was 1% higher than other three methods. For the image samples with simple backgrounds, such as cold rolled steel strips, the computation time of RNAMlet was one-tenth of the other three MGA methods, while the defect identification rates obtained by RNAMlet were higher than the other three methods.

  8. 34 CFR 366.50 - What assurances shall a center provide and comply with?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 2 2010-07-01 2010-07-01 false What assurances shall a center provide and comply with... LIVING Assurances for Centers § 366.50 What assurances shall a center provide and comply with? To be eligible for assistance under this part, an eligible agency shall provide satisfactory assurances that— (a...

  9. Geometric Defects in Quantum Hall States

    NASA Astrophysics Data System (ADS)

    Gromov, Andrey

    I will describe a geometric analogue of Laughlin quasiholes in fractional quantum Hall (FQH) states. These ``quasiholes'' are generated by an insertion of quantized fluxes of curvature - which can be modeled by branch points of a certain Riemann surface - and, consequently, are related to genons. Unlike quasiholes, the genons are not excitations, but extrinsic defects. Fusion of genons describes the response of an FQH state to a process that changes (effective) topology of the physical space. These defects are abelian for IQH states and non-abelian for FQH states. I will explain how to calculate an electric charge, geometric spin and adiabatic mutual statistics of the these defects. Leo Kadanoff Fellowship.

  10. Model based defect characterization in composites

    NASA Astrophysics Data System (ADS)

    Roberts, R.; Holland, S.

    2017-02-01

    Work is reported on model-based defect characterization in CFRP composites. The work utilizes computational models of the interaction of NDE probing energy fields (ultrasound and thermography), to determine 1) the measured signal dependence on material and defect properties (forward problem), and 2) an assessment of performance-critical defect properties from analysis of measured NDE signals (inverse problem). Work is reported on model implementation for inspection of CFRP laminates containing multi-ply impact-induced delamination, with application in this paper focusing on ultrasound. A companion paper in these proceedings summarizes corresponding activity in thermography. Inversion of ultrasound data is demonstrated showing the quantitative extraction of damage properties.

  11. Mass defect effects in atomic clocks

    NASA Astrophysics Data System (ADS)

    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.

  12. Chornobyl, radiation, neural tube defects, and microcephaly.

    PubMed

    Wertelecki, Wladimir; Yevtushok, Lyubov; Kuznietsov, Illia; Komov, Oleksandr; Lapchenko, Serhii; Akhmedzanova, Diana; Ostapchuk, Lyubov

    2018-06-13

    Pregnant women residing in areas impacted by the Chornobyl ionizing radiation of the Rivne Province in Ukraine have persistent higher levels of incorporated cesium-137. In these areas the neural tube defects and microcephaly rates are significantly higher than in areas with lower maternal cesium-137 incorporated levels. In two Rivne counties with populations proximal to nuclear power plants the rates of neural tube defects and microcephaly are the highest in the province. The neural tube defects rates in Rivne are persistently among the highest in Europe. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  13. Residual Defect Density in Random Disks Deposits.

    PubMed

    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.

  14. Infrared computations of defect Schur indices

    DOE PAGES

    Córdova, Clay; Gaiotto, Davide; Shao, Shu-Heng

    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 algebramore » and that for Argyres-Douglas theories the line defect OPE reduces in the index to the Verlinde algebra.« less

  15. Oral telangiectatic granuloma with an intrabony defect.

    PubMed

    Rathore, Akanksha; Jadhav, Tanya; Kulloli, Anita; Singh, Archana

    2015-01-01

    Oral telangiectatic granuloma is a benign hyperplastic lesion occurring in response to trauma or chronic irritation in the oral cavity. The characteristic histological appearance comprises of typical granulation tissue with a proliferation of small thin-walled blood vessels in the loose connective tissue. We describe a case of a 36-year-old female who had a swelling in the left maxillary region which was associated with the intrabony defect. An internal bevel gingivectomy was performed, and the histopathological report was suggestive of telangiectatic granuloma. The intrabony defect was managed with the placement of platelet rich fibrin plug in the defect. A follow-up at 6 months showed no recurrence and no loss in the width of keratinized tissue. The aim of this case is to highlight the rare association of intrabony defect with telangiectatic granuloma and the need for histopathological diagnosis in such lesions.

  16. Oral telangiectatic granuloma with an intrabony defect

    PubMed Central

    Rathore, Akanksha; Jadhav, Tanya; Kulloli, Anita; Singh, Archana

    2015-01-01

    Oral telangiectatic granuloma is a benign hyperplastic lesion occurring in response to trauma or chronic irritation in the oral cavity. The characteristic histological appearance comprises of typical granulation tissue with a proliferation of small thin-walled blood vessels in the loose connective tissue. We describe a case of a 36-year-old female who had a swelling in the left maxillary region which was associated with the intrabony defect. An internal bevel gingivectomy was performed, and the histopathological report was suggestive of telangiectatic granuloma. The intrabony defect was managed with the placement of platelet rich fibrin plug in the defect. A follow-up at 6 months showed no recurrence and no loss in the width of keratinized tissue. The aim of this case is to highlight the rare association of intrabony defect with telangiectatic granuloma and the need for histopathological diagnosis in such lesions. PMID:26941527

  17. This Issue: Correlates of a Defective School.

    ERIC Educational Resources Information Center

    Gilman, David Alan

    1992-01-01

    Describes correlates of defective schools: perks for very few; faulty communication; adult-centered programs; special interest group indulgence; poor professional relationships; personnel warehousing; incompetent consultants; literal interpretation of technicalities; imperial leadership; intimate relationships among personnel; incoherent…

  18. Genetic Counseling for Congenital Heart Defects

    MedlinePlus

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

  19. 47 CFR 1.746 - Defective applications.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., and Reports Involving Common Carriers Applications § 1.746 Defective applications. (a) Applications... will be accepted for filing and consideration if accompanied by petition showing good cause for waiver...

  20. 47 CFR 1.746 - Defective applications.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., and Reports Involving Common Carriers Applications § 1.746 Defective applications. (a) Applications... will be accepted for filing and consideration if accompanied by petition showing good cause for waiver...

  1. Reduction of Defects in Jewelry Manufacturing

    NASA Astrophysics Data System (ADS)

    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. 49 CFR 176.156 - Defective packages.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... packages. (a) No leaking, broken, or otherwise defective package containing Class 1 (explosive) materials.... (b) No Class 1 (explosive) material, which for any reason has deteriorated or undergone a change of...

  3. Phase measurements of EUV mask defects

    DOE PAGES

    Claus, Rene A.; Wang, Yow-Gwo; Wojdyla, Antoine; ...

    2015-02-22

    Extreme Ultraviolet (EUV) Lithography mask defects were examined on the actinic mask imaging system, SHARP, at Lawrence Berkeley National Laboratory. Also, a quantitative phase retrieval algorithm based on the Weak Object Transfer Function was applied to the measured through-focus aerial images to examine the amplitude and phase of the defects. The accuracy of the algorithm was demonstrated by comparing the results of measurements using a phase contrast zone plate and a standard zone plate. Using partially coherent illumination to measure frequencies that would otherwise fall outside the numerical aperture (NA), it was shown that some defects are smaller than themore » conventional resolution of the microscope. We found that the programmed defects of various sizes were measured and shown to have both an amplitude and a phase component that the algorithm is able to recover.« less

  4. When Your Baby Has a Birth Defect

    MedlinePlus

    ... as heart defects, cleft lip and palate, or cerebral palsy. Still, you may find yourself being both the ... the NICU Gene Therapy and Children Down Syndrome Cerebral Palsy Spina Bifida Prenatal Genetic Counseling What Is a ...

  5. Opioid Use and Neural Tube Defects

    MedlinePlus

    ... CDC.gov . Error processing SSI file Key Findings: Opioid Use and Neural Tube Defects Recommend on Facebook ... new study that looked at the use of opioids during pregnancy and their relationship to having a ...

  6. Infrared computations of defect Schur indices

    SciTech Connect

    Córdova, Clay; Gaiotto, Davide; Shao, Shu-Heng

    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 algebramore » and that for Argyres-Douglas theories the line defect OPE reduces in the index to the Verlinde algebra.« less

  7. International conference on defects in insulating crystals

    SciTech Connect

    Not Available

    1977-01-01

    Short summaries of conference papers are presented. Some of the conference topics included transport properties, defect levels, superionic conductors, radiation effects, John-Teller effect, electron-lattice interactions, and relaxed excited states. (SDF)

  8. 47 CFR 25.112 - Defective applications.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... application requests authority to operate a space station in a frequency band that is not allocated...) Applications for space station authority found defective under paragraph (a)(3) of this section will not be...

  9. 47 CFR 25.112 - Defective applications.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... application requests authority to operate a space station in a frequency band that is not allocated...) Applications for space station authority found defective under paragraph (a)(3) of this section will not be...

  10. 47 CFR 25.112 - Defective applications.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... application requests authority to operate a space station in a frequency band that is not allocated...) Applications for space station authority found defective under paragraph (a)(3) of this section will not be...

  11. 47 CFR 25.112 - Defective applications.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... application requests authority to operate a space station in a frequency band that is not allocated...) Applications for space station authority found defective under paragraph (a)(3) of this section will not be...

  12. 47 CFR 25.112 - Defective applications.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... application requests authority to operate a space station in a frequency band that is not allocated... § 25.158. (b) Applications for space station authority found defective under paragraph (a)(3) of this...

  13. Defect scanning technology in the works

    Treesearch

    Philip A. Araman; R. Conners

    1994-01-01

    This article describes the defect scanning technology being developed by Virginia Tech and U.S. Forest Service scientists in Blacksburg, Virginia to scan full sized hardwood lumber at industrial speeds.

  14. Living with a Congenital Heart Defect

    MedlinePlus

    ... to live as healthy a life as possible. Stories: Living with a Congenital Heart Defect William's Story ... Story Shandler's story Nicholas' Story Ken's Story William's Story William’s Story I was born with a heart ...

  15. Genetics Home Reference: abdominal wall defect

    MedlinePlus

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

  16. Microcephaly and Other Birth Defects: Zika

    MedlinePlus

    ... Español (Spanish) Recommend on Facebook Tweet Share Compartir Zika and Microcephaly Microcephaly is a birth defect in ... pregnancy or has stopped growing after birth. Congenital Zika Syndrome Congenital Zika syndrome is a unique pattern ...

  17. Neutron-induced defects in optical fibers

    SciTech Connect

    Rizzolo, S., E-mail: serena.rizzolo@univ-st-etienne.fr; Dipartimento di Fisica e Chimica, Università di Palermo, Palermo; and Areva Centre Technique, Le Creusot

    2014-10-21

    We present a study on 0.8 MeV neutron-induced defects up to fluences of 10{sup 17} n/cm{sup 2} in fluorine doped optical fibers by using electron paramagnetic resonance, optical absorption and confocal micro-luminescence techniques. Our results allow to address the microscopic mechanisms leading to the generation of Silica-related point-defects such as E', H(I), POR and NBOH Centers.

  18. [SOX2 defect and anophthalmia and microphthalmia].

    PubMed

    Ye, Fu-xiang; Fan, Xian-qun

    2012-11-01

    As a severe congenital developmental disorder, anophthalmia and microphthalmia are usually accompanied with vision impairment and hypoevolutism of the orbit in the affected side. Many genes are involved in anophthalmia and microphthalmia, in which, SOX2 is an important one. The defect of SOX2 causes multiple system disorders, including anophthalmia and microphthalmia. We describe the relationship between the SOX2 defect and anophthalmia/microphthalmia, in order to offer some proposals for the differential diagnosis, treatment and research of anophthalmia and microphthalmia.

  19. Defects and Transport in Lithium Niobium Trioxide

    NASA Astrophysics Data System (ADS)

    Mehta, Apurva

    1990-01-01

    This dissertation presents work done on characterizing the defects and transport properties of congruent LiNbO _3. The focus of the study is the high temperature (800^circC to 1000^circC) equilibrium defect structure. The majority defects are described in terms of the 'LiNbO_3-ilmenite' defect model previously presented (26). Here the emphasis is placed on quantifying the defect concentrations. Congruent LiNbO_3 is highly nonstoichiometric. The large concentration of ionic defects present are mobile and contribute to electrical conduction. The ionic conduction was separated from the total conduction using defect chemistry and the transference number thus obtained was checked against the transference number obtained in a galvanic cell measurement. LiNbO_3 is an insulator (band gap = 4 eV). Hence one assumes that almost all of the conduction electrons are created by reduction. The degree of oxygen nonstoichiometry, a measure of the extent of chemical reduction, and the electron concentrations, were quantified as a function of oxygen partial pressure and the temperature by coulometric titration. The nonstoichiometry thus obtained was compared with nonstoichiometry obtained by TGA measurements. By fixing the phase composition of the sample in a buffered system, a set of constant composition measurements could be undertaken. These constant composition measurements were used to obtain the enthalpy of formation of conduction electrons, 1.95 eV, and the hopping energy for their motion at elevated temperatures, 0.55 eV, independently. The sum of the two energies was obtained by measuring the temperature dependence of the electronic conduction. The sum of the energies was found to be in excellent agreement with the energy obtained from equilibrium conduction. In conclusion, a quantitative and self-consistent picture of defects and their migration in LiNbO _3 was obtained.

  20. 49 CFR 215.103 - Defective wheel.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... less; (d) A wheel rim, flange, plate, or hub area on the car has a crack or break; (e) A wheel on the... 49 Transportation 4 2012-10-01 2012-10-01 false Defective wheel. 215.103 Section 215.103... § 215.103 Defective wheel. A railroad may not place or continue in service a car, if— (a) A wheel flange...

  1. 49 CFR 215.103 - Defective wheel.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... less; (d) A wheel rim, flange, plate, or hub area on the car has a crack or break; (e) A wheel on the... 49 Transportation 4 2011-10-01 2011-10-01 false Defective wheel. 215.103 Section 215.103... § 215.103 Defective wheel. A railroad may not place or continue in service a car, if— (a) A wheel flange...

  2. 49 CFR 215.103 - Defective wheel.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... less; (d) A wheel rim, flange, plate, or hub area on the car has a crack or break; (e) A wheel on the... 49 Transportation 4 2010-10-01 2010-10-01 false Defective wheel. 215.103 Section 215.103... § 215.103 Defective wheel. A railroad may not place or continue in service a car, if— (a) A wheel flange...

  3. 49 CFR 215.103 - Defective wheel.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... less; (d) A wheel rim, flange, plate, or hub area on the car has a crack or break; (e) A wheel on the... 49 Transportation 4 2014-10-01 2014-10-01 false Defective wheel. 215.103 Section 215.103... § 215.103 Defective wheel. A railroad may not place or continue in service a car, if— (a) A wheel flange...

  4. 49 CFR 215.103 - Defective wheel.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... less; (d) A wheel rim, flange, plate, or hub area on the car has a crack or break; (e) A wheel on the... 49 Transportation 4 2013-10-01 2013-10-01 false Defective wheel. 215.103 Section 215.103... § 215.103 Defective wheel. A railroad may not place or continue in service a car, if— (a) A wheel flange...

  5. Defect structure of web silicon ribbon

    NASA Technical Reports Server (NTRS)

    Cunningham, B.; Strunk, H.; Ast, D.

    1980-01-01

    The results of a preliminary study of two dendritic web samples are presented. The structure and electrical activity of the defects in the silicon webs were studied. Optical microscopy of chemically etched specimens was used to determine dislocation densities. Samples were mechanically polished, then Secco etched for approximately 5 minutes. High voltage transmission electron microscopy was used to characterize the crystallographic nature of the defects.

  6. Lassoing saddle splay and the geometrical control of topological defects

    NASA Astrophysics Data System (ADS)

    Tran, Lisa; Lavrentovich, Maxim O.; Beller, Daniel A.; Li, Ningwei; Stebe, Kathleen J.; Kamien, Randall D.

    2016-06-01

    Systems with holes, such as colloidal handlebodies and toroidal droplets, have been studied in the nematic liquid crystal (NLC) 4-cyano-4'-pentylbiphenyl (5CB): Both point and ring topological defects can occur within each hole and around the system while conserving the system's overall topological charge. However, what has not been fully appreciated is the ability to manipulate the hole geometry with homeotropic (perpendicular) anchoring conditions to induce complex, saddle-like deformations. We exploit this by creating an array of holes suspended in an NLC cell with oriented planar (parallel) anchoring at the cell boundaries. We study both 5CB and a binary mixture of bicyclohexane derivatives (CCN-47 and CCN-55). Through simulations and experiments, we study how the bulk saddle deformations of each hole interact to create defect structures, including an array of disclination lines, reminiscent of those found in liquid-crystal blue phases. The line locations are tunable via the NLC elastic constants, the cell geometry, and the size and spacing of holes in the array. This research lays the groundwork for the control of complex elastic deformations of varying length scales via geometrical cues in materials that are renowned in the display industry for their stability and easy manipulability.

  7. Lassoing saddle splay and the geometrical control of topological defects

    PubMed Central

    Tran, Lisa; Lavrentovich, Maxim O.; Beller, Daniel A.; Li, Ningwei; Stebe, Kathleen J.; Kamien, Randall D.

    2016-01-01

    Systems with holes, such as colloidal handlebodies and toroidal droplets, have been studied in the nematic liquid crystal (NLC) 4-cyano-4′-pentylbiphenyl (5CB): Both point and ring topological defects can occur within each hole and around the system while conserving the system’s overall topological charge. However, what has not been fully appreciated is the ability to manipulate the hole geometry with homeotropic (perpendicular) anchoring conditions to induce complex, saddle-like deformations. We exploit this by creating an array of holes suspended in an NLC cell with oriented planar (parallel) anchoring at the cell boundaries. We study both 5CB and a binary mixture of bicyclohexane derivatives (CCN-47 and CCN-55). Through simulations and experiments, we study how the bulk saddle deformations of each hole interact to create defect structures, including an array of disclination lines, reminiscent of those found in liquid-crystal blue phases. The line locations are tunable via the NLC elastic constants, the cell geometry, and the size and spacing of holes in the array. This research lays the groundwork for the control of complex elastic deformations of varying length scales via geometrical cues in materials that are renowned in the display industry for their stability and easy manipulability. PMID:27222582

  8. Neural Network Classifiers to Grade Parts Based on Surface Defects with Spatial Dependencies

    Treesearch

    Daniel L. Schmoldt

    1995-01-01

    In many manufacturing situations, production parts must be assigned a qualitative grade, rather than only accepted or rejected. When this is done, spatial relationships between defect areas can be a critical factor in making grade assignments. In the case of grading hardwood lumber, for instance, there exists a highly complex set of grading rules which incorporate...

  9. Treatment of gun-shot defect of the foot with bovine collagen matrix application.

    PubMed

    Coban, Yusuf Kenan; Kalender, Ali Murat

    2009-12-01

    Nonoperative therapy might be chosen for patients with small wounds or defects around the foot and ankle region. Lyophilized bovine collagen matrix is one of ideal biological dressings used in wound treatment. We present an example of type 1 bovine collagen (Gelfix, Euroresearch, Inc., Milano, Italy) usage in a complex gun-shot wound of the foot and relevant literature is discussed.

  10. Infrared studies of defects formed during postirradiation anneals of Czochralski silicon

    NASA Astrophysics Data System (ADS)

    Londos, C. A.; Sarlis, N. V.; Fytros, L. G.

    1998-10-01

    This article reports on defect studies of neutron-irradiated Czochralski-grown silicon (Cz-Si) material by means of infrared spectroscopy. In particular, the investigation was focused on the evolution of the 828 cm-1 well-known band of A-center, due to isochronal anneals from room temperature (RT) up to ≈700 °C. The strength of the VO band begins to increase above ≈200 gradually up to 300 °C (stage I); then, it begins to decrease up to ≈400 °C (stage II), where upon it stabilizes up to ≈550 °C (stage III). Upon re-irradiation under exactly the same conditions and repeating the annealing process, the increase of the VO signal in stage I disappears. The phenomenon is ascribed to the existence of defect aggregates labeled as Xi centers which are correlated with (impurity-defect) clusters that compete with Oi in capturing vacancies. The presence of Xi centers is related to the thermal annealings performed. Comparison of the evolution of VO (828 cm-1) and VO2 (887 cm-1) bands between irradiated and re-irradiated materials, during stage II, is made and the results are discussed in the framework of established reaction patterns. The stabilization of the amplitude of the 828 cm-1 line in stage III is examined. The prevailing aspect is that a portion of A-centers in neutron-irradiated Si acquires larger thermal stability by relaxing in the vicinity of larger defects.

  11. Topological Defects in Liquid Crystals: Studying the Correlation between Defects and Curvature

    NASA Astrophysics Data System (ADS)

    Melton, Charles

    2015-03-01

    Topological defects have recently been the subject of many fascinating studies in soft condensed matter physics. In particular, linking the evolution of topological defects to curvature changes has been a focus, leading possible applications in the areas such as cosmetics, pharmaceuticals, and electronics. In this study, defects in nematic liquid crystal droplets are investigated via laboratory and theoretical techniques. Nematic liquid crystal defects are reproduced via Monte Carlo simulations using a modified 2D XY-Model Hamiltonian. The simulation is performed on a curved surface to replicate a nematic droplet and examine possible defect configurations. To complement this theoretical work, we have trapped nematic droplets inside a dual-beam optical trap. This system allows controllable non-contact droplet deformation on a microscope based platform. Future work will focus on using the trap to stretch nematic droplets, correlating the changing topological defects with theoretical predictions.

  12. Defects and Small Polarons on Oxide Surfaces

    NASA Astrophysics Data System (ADS)

    Janotti, Anderson

    The presence and behavior of defects on the surface of oxides are central in many research areas, including catalysis, photochemistry, solar cells, and surface science in general. Experimental characterization of individual defects and their activities are challenging and often requires special preparations of the surface. First-principles calculations based on density functional theory are a powerful tool to study surfaces and defects, often providing information on properties that are difficult to access experimentally. Here we discuss the behavior of defects on oxide surfaces from the perspective on first-principles calculations. We use the oxygen vacancy on TiO2 surface as example, a system that has been extensively reported in the literature. Using DFT with a hybrid function, we discuss surface states induced by the defect and localization of the excess charge in the form of small polarons. We then discuss the effects of hydrogen and compare the behavior of these defects on the surface with that in the bulk. We also compare our recent results with previous theoretical studies and experiments. Finally, we generalize the findings on TiO2 to the surfaces of other oxides. This work was supported by the NSF.

  13. Congenital heart defects in Williams syndrome.

    PubMed

    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.

  14. A novel inspection system for cosmetic defects

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  15. Defect Tolerant Semiconductors for Solar Energy Conversion.

    PubMed

    Zakutayev, Andriy; Caskey, Christopher M; Fioretti, Angela N; Ginley, David S; Vidal, Julien; Stevanovic, Vladan; Tea, Eric; Lany, Stephan

    2014-04-03

    Defect tolerance is the tendency of a semiconductor to keep its properties despite the presence of crystallographic defects. Scientific understanding of the origin of defect tolerance is currently missing. Here we show that semiconductors with antibonding states at the top of the valence band are likely to be tolerant to defects. Theoretical calculations demonstrate that Cu3N with antibonding valence band maximum has shallow intrinsic defects and no surface states, in contrast to GaN with bonding valence band maximum. Experimental measurements indicate shallow native donors and acceptors in Cu3N thin films, leading to 10(16)-10(17) cm(-3) doping with either electrons or holes depending on the growth conditions. The experimentally measured bipolar doping and the solar-matched optical absorption onset (1.4 eV) make Cu3N a promising candidate absorber for photovoltaic and photoelectrochemical solar cells, despite the calculated indirect fundamental band gap (1.0 eV). These conclusions can be extended to other materials with antibonding character of the valence band, defining a class of defect-tolerant semiconductors for solar energy conversion applications.

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

    NASA Astrophysics Data System (ADS)

    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.

  17. Defect detection of castings in radiography images using a robust statistical feature.

    PubMed

    Zhao, Xinyue; He, Zaixing; Zhang, Shuyou

    2014-01-01

    One of the most commonly used optical methods for defect detection is radiographic inspection. Compared with methods that extract defects directly from the radiography image, model-based methods deal with the case of an object with complex structure well. However, detection of small low-contrast defects in nonuniformly illuminated images is still a major challenge for them. In this paper, we present a new method based on the grayscale arranging pairs (GAP) feature to detect casting defects in radiography images automatically. First, a model is built using pixel pairs with a stable intensity relationship based on the GAP feature from previously acquired images. Second, defects can be extracted by comparing the difference of intensity-difference signs between the input image and the model statistically. The robustness of the proposed method to noise and illumination variations has been verified on casting radioscopic images with defects. The experimental results showed that the average computation time of the proposed method in the testing stage is 28 ms per image on a computer with a Pentium Core 2 Duo 3.00 GHz processor. For the comparison, we also evaluated the performance of the proposed method as well as that of the mixture-of-Gaussian-based and crossing line profile methods. The proposed method achieved 2.7% and 2.0% false negative rates in the noise and illumination variation experiments, respectively.

  18. Point defects in Cd(Zn)Te and TlBr: Theory

    NASA Astrophysics Data System (ADS)

    Lordi, Vincenzo

    2013-09-01

    The effects of various crystal defects on the performances of CdTe, CdZnxTe (CZT), and TlBr for room-temperature high-energy radiation detection are examined using first-principles theoretical methods. The predictive, parameter-free, atomistic approaches used provide fundamental understanding of defect properties that are difficult to measure and also allow rapid screening of possibilities for material engineering, such as optimal doping and annealing conditions. Several recent examples from the author's work are reviewed, including: (i) accurate calculations of the thermodynamic and electronic properties of native point defects and point defect complexes in CdTe and CZT; (ii) the effects of Zn alloying on the native point defect properties in CZT; (iii) point defect diffusion and binding leading to Te clustering in Cd(Zn)Te; (iv) the profound effect of native point defects—principally vacancies—on the intrinsic material properties of TlBr, particularly its electronic and ionic conductivity; and (v) a study on doping TlBr to independently control the electronic and ionic conductivity.

  19. Simple intrinsic defects in GaP and InP

    NASA Astrophysics Data System (ADS)

    Schultz, Peter A.

    2012-02-01

    To faithfully simulate evolution of defect chemistry and electrical response in irradiated semiconductor devices requires accurate defect reaction energies and energy levels. In III-Vs, good data is scarce, theory hampered by band gap and supercell problems. I apply density functional theory (DFT) to intrinsic defects in GaP and InP, predicting stable charge states, ground state configurations, defect energy levels, and identifying mobile species. The SeqQuest calculations incorporate rigorous charge boundary conditions removing supercell artifacts, demonstrated converged to the infinite limit. Computed defect levels are not limited by a band gap problem, despite Kohn-Sham gaps much smaller than the experimental gap. As in GaAs, [P.A. Schultz and O.A. von Lilienfeld, Modeling Simul. Mater. Sci. Eng. 17, 084007 (2009)], defects in GaP and InP exhibit great complexity---multitudes of charge states, bistabilities, and negative U systems---but show similarities to each other (and to GaAs). Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Company, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  20. Defect detection and classification of galvanized stamping parts based on fully convolution neural network

    NASA Astrophysics Data System (ADS)

    Xiao, Zhitao; Leng, Yanyi; Geng, Lei; Xi, Jiangtao

    2018-04-01

    In this paper, a new convolution neural network method is proposed for the inspection and classification of galvanized stamping parts. Firstly, all workpieces are divided into normal and defective by image processing, and then the defective workpieces extracted from the region of interest (ROI) area are input to the trained fully convolutional networks (FCN). The network utilizes an end-to-end and pixel-to-pixel training convolution network that is currently the most advanced technology in semantic segmentation, predicts result of each pixel. Secondly, we mark the different pixel values of the workpiece, defect and background for the training image, and use the pixel value and the number of pixels to realize the recognition of the defects of the output picture. Finally, the defect area's threshold depended on the needs of the project is set to achieve the specific classification of the workpiece. The experiment results show that the proposed method can successfully achieve defect detection and classification of galvanized stamping parts under ordinary camera and illumination conditions, and its accuracy can reach 99.6%. Moreover, it overcomes the problem of complex image preprocessing and difficult feature extraction and performs better adaptability.

  1. Fabric defect detection based on visual saliency using deep feature and low-rank recovery

    NASA Astrophysics Data System (ADS)

    Liu, Zhoufeng; Wang, Baorui; Li, Chunlei; Li, Bicao; Dong, Yan

    2018-04-01

    Fabric defect detection plays an important role in improving the quality of fabric product. In this paper, a novel fabric defect detection method based on visual saliency using deep feature and low-rank recovery was proposed. First, unsupervised training is carried out by the initial network parameters based on MNIST large datasets. The supervised fine-tuning of fabric image library based on Convolutional Neural Networks (CNNs) is implemented, and then more accurate deep neural network model is generated. Second, the fabric images are uniformly divided into the image block with the same size, then we extract their multi-layer deep features using the trained deep network. Thereafter, all the extracted features are concentrated into a feature matrix. Third, low-rank matrix recovery is adopted to divide the feature matrix into the low-rank matrix which indicates the background and the sparse matrix which indicates the salient defect. In the end, the iterative optimal threshold segmentation algorithm is utilized to segment the saliency maps generated by the sparse matrix to locate the fabric defect area. Experimental results demonstrate that the feature extracted by CNN is more suitable for characterizing the fabric texture than the traditional LBP, HOG and other hand-crafted features extraction method, and the proposed method can accurately detect the defect regions of various fabric defects, even for the image with complex texture.

  2. Dynamic defect correlations dominate activated electronic transport in SrTiO 3

    DOE PAGES

    Snijders, Paul C.; Sen, Cengiz; McConnell, Michael P.; ...

    2016-07-22

    Strontium titanate (SrTiO 3, STO) is a critically important material for the study of emergent electronic phases in complex oxides, as well as for the development of applications based on their heterostructures. Despite the large body of knowledge on STO, there are still many uncertainties regarding the role of defects in the properties of STO, including their influence on ferroelectricity in bulk STO and ferromagnetism in STO-based heterostructures. In this paper, we present a detailed analysis of the decay of persistent photoconductivity in STO single crystals with defect concentrations that are relatively low but significantly affect their electronic properties. Themore » results show that photo-activated electron transport cannot be described by a superposition of the properties due to independent point defects as current models suggest but is, instead, governed by defect complexes that interact through dynamic correlations. In conclusion, these results emphasize the importance of defect correlations for activated electronic transport properties of semiconducting and insulating perovskite oxides.« less

  3. Designing Complexity

    ERIC Educational Resources Information Center

    Glanville, Ranulph

    2007-01-01

    This article considers the nature of complexity and design, as well as relationships between the two, and suggests that design may have much potential as an approach to improving human performance in situations seen as complex. It is developed against two backgrounds. The first is a world view that derives from second order cybernetics and radical…

  4. Complexity Theory

    USGS Publications Warehouse

    Lee, William H K.

    2016-01-01

    A complex system consists of many interacting parts, generates new collective behavior through self organization, and adaptively evolves through time. Many theories have been developed to study complex systems, including chaos, fractals, cellular automata, self organization, stochastic processes, turbulence, and genetic algorithms.

  5. USE OF BIOCERAMICS IN FILLING BONE DEFECTS

    PubMed Central

    Garrido, Carlos Antõnio; Sampaio, Tania Clarete Fonseca Vieira Sales

    2015-01-01

    Objective: To present the results from using biological ceramics for filling bone defects resulting from post-traumatic or orthopedic injuries. Methods: Thirty-six patients with bone defects caused by trauma or orthopedic injury were evaluated. Nineteen patients were male (52.8%) and 17 were female (47.2%). Their ages ranged from 19 to 84 years, with a mean of 45.7 years and median of 37 years. Only patients with defects that required at least five grams of biological ceramic were included. Eighteen cases were classified as orthopedic: bone defects were observed in 11 cases of total hip arthroplasty; one case of primary total hip arthroplasty, due to coxarthrosis; five cases of femoral or tibial open wedge osteotomy; and one case of tarsal arthrodesis. There were 18 cases of trauma-related defects; uninfected pseudarthrosis, eight cases; recent fractures of the tibial plateau with compression of the spongy bone, three cases; and exposed fractures treated with external fixators, seven cases. The surgical technique consisted of curetting and debriding the injury until bone suitable for grafting was found. Biological ceramic was then used to fill the defect and some kind of fixation was applied. Results: Among the 36 patients evaluated, it was seen that 35 (97.2%) presented integration of the biological ceramic, while one case of open fracture treated with external fixation had poor integration of the biological ceramic. Conclusion: Treatment of bone defects of orthopedic or post-traumatic etiology using a phosphocalcium ceramic composed of hydroxyapatite was shown to be a practical, effective and safe method. PMID:27022576

  6. Comparison of binary mask defect printability analysis using virtual stepper system and aerial image microscope system

    NASA Astrophysics Data System (ADS)

    Phan, Khoi A.; Spence, Chris A.; Dakshina-Murthy, S.; Bala, Vidya; Williams, Alvina M.; Strener, Steve; Eandi, Richard D.; Li, Junling; Karklin, Linard

    1999-12-01

    As advanced process technologies in the wafer fabs push the patterning processes toward lower k1 factor for sub-wavelength resolution printing, reticles are required to use optical proximity correction (OPC) and phase-shifted mask (PSM) for resolution enhancement. For OPC/PSM mask technology, defect printability is one of the major concerns. Current reticle inspection tools available on the market sometimes are not capable of consistently differentiating between an OPC feature and a true random defect. Due to the process complexity and high cost associated with the making of OPC/PSM reticles, it is important for both mask shops and lithography engineers to understand the impact of different defect types and sizes to the printability. Aerial Image Measurement System (AIMS) has been used in the mask shops for a number of years for reticle applications such as aerial image simulation and transmission measurement of repaired defects. The Virtual Stepper System (VSS) provides an alternative method to do defect printability simulation and analysis using reticle images captured by an optical inspection or review system. In this paper, pre- programmed defects and repairs from a Defect Sensitivity Monitor (DSM) reticle with 200 nm minimum features (at 1x) will be studied for printability. The simulated resist lines by AIMS and VSS are both compared to SEM images of resist wafers qualitatively and quantitatively using CD verification.Process window comparison between unrepaired and repaired defects for both good and bad repair cases will be shown. The effect of mask repairs to resist pattern images for the binary mask case will be discussed. AIMS simulation was done at the International Sematech, Virtual stepper simulation at Zygo and resist wafers were processed at AMD-Submicron Development Center using a DUV lithographic process for 0.18 micrometer Logic process technology.

  7. Associations between maternal periconceptional exposure to secondhand tobacco smoke and major birth defects.

    PubMed

    Hoyt, Adrienne T; Canfield, Mark A; Romitti, Paul A; Botto, Lorenzo D; Anderka, Marlene T; Krikov, Sergey V; Tarpey, Morgan K; Feldkamp, Marcia L

    2016-11-01

    isolated and total case groups for various sources of exposure (household only; workplace/school only; household and workplace/school; household or workplace/school). The prevalence of secondhand smoke exposure only across all sources ranged from 12.9-27.8% for cases and 14.5-15.8% for controls. The adjusted odds ratios for any vs no secondhand smoke exposure in the household or workplace/school and isolated birth defects were significantly elevated for neural tube defects (anencephaly: adjusted odds ratio, 1.66; 95% confidence interval, 1.22-2.25; and spina bifida: adjusted odds ratio, 1.49; 95% confidence interval, 1.20-1.86); orofacial clefts (cleft lip without cleft palate: adjusted odds ratio, 1.41; 95% confidence interval, 1.10-1.81; cleft lip with or without cleft palate: adjusted odds ratio, 1.24; 95% confidence interval, 1.05-1.46; cleft palate alone: adjusted odds ratio, 1.31; 95% confidence interval, 1.06-1.63); bilateral renal agenesis (adjusted odds ratio, 1.99; 95% confidence interval, 1.05-3.75); amniotic band syndrome-limb body wall complex (adjusted odds ratio, 1.66; 95% confidence interval, 1.10-2.51); and atrial septal defects, secundum (adjusted odds ratio, 1.37; 95% confidence interval, 1.09-1.72). There were no significant inverse associations observed. Additional studies replicating the findings are needed to better understand the moderate positive associations observed between periconceptional secondhand smoke and several birth defects in this analysis. Increased odds ratios resulting from chance (eg, multiple comparisons) or recall bias cannot be ruled out. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. 7 CFR 51.2954 - Tolerances for grade defects.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... chart. Tolerances for Grade Defects Grade External (shell) defects Internal (kernel) defects Color of kernel U.S. No. 1. 10 pct, by count for splits. 5 pct. by count, for other shell defects, including not... tolerance to reduce the required 70 pct of “light amber” kernels or the required 40 pct of “light” kernels...

  9. Hardwood log defect photographic database, software and user's guide

    Treesearch

    R. Edward Thomas

    2009-01-01

    Computer software and user's guide for Hardwood Log Defect Photographic Database. The database contains photographs and information on external hardwood log defects and the corresponding internal characteristics. This database allows users to search for specific defect types, sizes, and locations by tree species. For every defect, the database contains photos of...

  10. Observation of defects evolution in electronic materials

    NASA Astrophysics Data System (ADS)

    Jang, Jung Hun

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

  11. Bendectin and birth defects. II: Ecological analyses.

    PubMed

    Kutcher, Jeffrey S; Engle, Arnold; Firth, Jacqueline; Lamm, Steven H

    2003-02-01

    Bendectin was the primary pharmaceutical treatment of nausea and vomiting of pregnancy (NVP) in the United States until the early 1980s. Its manufacture was then discontinued after public allegations that it was causing birth defects. Subsequently, meta-analyses of the many epidemiological cohort and case/control studies used to examine that hypothesis have demonstrated the absence of a detectable teratogenic effect. This study presents an ecological analysis of the same hypothesis that examines specific malformations. Annual birth defect prevalence data for the 1970s to the 1990s have been obtained for specific birth defects from the Center for Disease Control's nationwide Birth Defect Monitoring Program. These data for the US have been compared graphically to the annual US Bendectin sales for the treatment of NVP. Data have also been obtained for annual US rates for hospitalization for NVP. The three data sets have been temporally compared in graphic analysis. The temporal trends in prevalence rates for specific birth defects examined from 1970 through 1992 did not show changes that reflected the cessation of Bendectin use over the 1980-84 period. Further, the NVP hospitalization rate doubled when Bendectin use ceased. The population results of the ecological analyses complement the person-specific results of the epidemiological analyses in finding no evidence of a teratogenic effect from the use of Bendectin.

  12. High purith low defect FZ silicon

    NASA Technical Reports Server (NTRS)

    Kimura, H.; Robertson, G.

    1985-01-01

    The most common intrinsic defects in dislocation-free float zone (FZ) silicon crystals are the A- and B-type swirl defects. The mechanisms of their formation and annihilation have been extensively studied. Another type of defect in dislocation-free FZ crystals is referred to as a D-type defect. Concentrations of these defects can be minimized by optimizing the growth conditions, and the residual swirls can be reduced by the post-growth extrinsic gettering process. Czochralski (Cz) silicon wafers are known to exhibit higher resistance to slip and warpage due to thermal stress than do FZ wafers. The Cz crystals containing dislocations are more resistant to dislocation movement than dislocated FZ crystals because of the locking of dislocations by oxygen atoms present in the Cz crystals. Recently a transverse magnetic field was applied during the FZ growth of extrinsic silicon. Resultant flow patterns, as revealed by striation etching and spreading resistance in Ga-doped silicon crystals, indicate strong effects of the transverse magnetic field on the circulation within the melt. At fields of 5500 gauss, the fluid flow in the melt volume is so altered as to affect the morphology of the growing crystal.

  13. Automatic casting surface defect recognition and classification

    NASA Astrophysics Data System (ADS)

    Wong, Boon K.; Elliot, M. P.; Rapley, C. W.

    1995-03-01

    High integrity castings require surfaces free from defects to reduce, if not eliminate, vulnerability to component failure from such as physical or thermal fatigue or corrosion attack. Previous studies have shown that defects on casting surfaces can be optically enhanced from the surrounding randomly textured surface by liquid penetrants, magnetic particle and other methods. However, very little has been reported on recognition and classification of the defects. The basic problem is one of shape recognition and classification, where the shape can vary in size and orientation as well as in actual shape generally within an envelope that classifies it as a particular defect. The initial work done towards this has focused on recognizing and classifying standard shapes such as the circle, square, rectangle and triangle. Various approaches were tried and this led eventually to a series of fuzzy logic based algorithms from which very good results were obtained. From this work fuzzy logic memberships were generated for the detection of defects found on casting surfaces. Simulated model shapes of such as the quench crack, mechanical crack and hole have been used to test the generated algorithm and the results for recognition and classification are very encouraging.

  14. Imaging active topological defects in carbon nanotubes

    NASA Astrophysics Data System (ADS)

    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. Color vision defects in school going children.

    PubMed

    Shrestha, R K; Joshi, M R; Shakya, S; Ghising, R

    2010-01-01

    Color vision defect can be observed in various diseases of optic nerve and retina and also a significant number of people suffer from the inherited condition of red and green color defect. A cross-sectional descriptive study was designed with purposive sampling of students from various schools of Kathmandu Valley. All children were subjected to color vision evaluation using Ishihara Isochromatic color plates along with other examination to rule out any other causes for color deficiency. A total of 2001 students were examined, 1050 male students and 951 females with mean age of 10.35 (+/- 2.75) and 10.54 (+/- 2.72) respectively. Among the total students examined, 2.1% had some form of color vision defects. Of the male population, 3.9% had color vision defects while none of the female was found with the deficiency. The prevalence of color vision defect in Nepal is significant and comparable with the prevalence quoted in studies from different countries.

  16. Congenital heart defects and extracardiac malformations.

    PubMed

    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.

  17. Structure Defect Property Relationships in Binary Intermetallics

    NASA Astrophysics Data System (ADS)

    Medasani, Bharat; Ding, Hong; Chen, Wei; Persson, Kristin; Canning, Andrew; Haranczyk, Maciej; Asta, Mark

    2015-03-01

    Ordered intermetallics are light weight materials with technologically useful high temperature properties such as creep resistance. Knowledge of constitutional and thermal defects is required to understand these properties. Vacancies and antisites are the dominant defects in the intermetallics and their concentrations and formation enthalpies could be computed by using first principles density functional theory and thermodynamic formalisms such as dilute solution method. Previously many properties of the intermetallics such as melting temperatures and formation enthalpies were statistically analyzed for large number of intermetallics using structure maps and data mining approaches. We undertook a similar exercise to establish the dependence of the defect properties in binary intermetallics on the underlying structural and chemical composition. For more than 200 binary intermetallics comprising of AB, AB2 and AB3 structures, we computed the concentrations and formation enthalpies of vacancies and antisites in a small range of stoichiometries deviating from ideal stoichiometry. The calculated defect properties were datamined to gain predictive capabilities of defect properties as well as to classify the intermetallics for their suitability in high-T applications. Supported by the US DOE under Contract No. DEAC02-05CH11231 under the Materials Project Center grant (Award No. EDCBEE).

  18. Coating defect evaluation based on stimulated thermography

    NASA Astrophysics Data System (ADS)

    Palumbo, Davide; Tamborrino, Rosanna; Galietti, Umberto

    2017-05-01

    Thermal Barrier Coatings are used to protect the materials from severe temperature and chemical environments. In particular, these materials are used in the engineering fields where high temperatures, corrosive environments and high mechanical stress are required. Defects present between substrate material and coating, as detachments may cause the break of coating and the consequent possibility to exposure the substrate material to the environment conditions. The capability to detect the defect zones with non-destructive techniques could allow the maintenance of coated components with great advantages in terms of costs and prediction of fatigue life. In this work, two different heat sources and two different thermographic techniques have been used to detect the adhesion defects among the base material and the coating. Moreover, an empirical thermographic method has been developed to evaluate the thickness of the thermal coating and to discriminate between an unevenness of the thickness and a defect zone. The study has been conducted on circular steel specimens with simulated adhesion defect and on specimens prepared with different thicknesses of thermal barrier coating.

  19. Ultrasonic NDE Simulation for Composite Manufacturing Defects

    NASA Technical Reports Server (NTRS)

    Leckey, Cara A. C.; Juarez, Peter D.

    2016-01-01

    The increased use of composites in aerospace components is expected to continue into the future. The large scale use of composites in aerospace necessitates the development of composite-appropriate nondestructive evaluation (NDE) methods to quantitatively characterize defects in as-manufactured parts and damage incurred during or post manufacturing. Ultrasonic techniques are one of the most common approaches for defect/damage detection in composite materials. One key technical challenge area included in NASA's Advanced Composite's Project is to develop optimized rapid inspection methods for composite materials. Common manufacturing defects in carbon fiber reinforced polymer (CFRP) composites include fiber waviness (in-plane and out-of-plane), porosity, and disbonds; among others. This paper is an overview of ongoing work to develop ultrasonic wavefield based methods for characterizing manufacturing waviness defects. The paper describes the development and implementation of a custom ultrasound simulation tool that is used to model ultrasonic wave interaction with in-plane fiber waviness (also known as marcelling). Wavefield data processing methods are applied to the simulation data to explore possible routes for quantitative defect characterization.

  20. White paper: A plan for cooperation between NASA and DARPA to establish a center for advanced architectures

    NASA Technical Reports Server (NTRS)

    Denning, P. J.; Adams, G. B., III; Brown, R. L.; Kanerva, P.; Leiner, B. M.; Raugh, M. R.

    1986-01-01

    Large, complex computer systems require many years of development. It is recognized that large scale systems are unlikely to be delivered in useful condition unless users are intimately involved throughout the design process. A mechanism is described that will involve users in the design of advanced computing systems and will accelerate the insertion of new systems into scientific research. This mechanism is embodied in a facility called the Center for Advanced Architectures (CAA). CAA would be a division of RIACS (Research Institute for Advanced Computer Science) and would receive its technical direction from a Scientific Advisory Board established by RIACS. The CAA described here is a possible implementation of a center envisaged in a proposed cooperation between NASA and DARPA.

  1. Defects in regular nanosystems and interference spectra at reemission of electromagnetic field attosecond pulses

    NASA Astrophysics Data System (ADS)

    Matveev, V. I.; Makarov, D. N.

    2017-01-01

    The effect of defects in nanostructured targets on interference spectra at the reemission of attosecond electromagnetic pulses has been considered. General expressions have been obtained for calculations of spectral distributions for one-, two-, and three-dimensional multiatomic nanosystems consisting of identical complex atoms with defects such as bends, vacancies, and breaks. Changes in interference spectra by a linear chain with several removed atoms (chain with breaks) and by a linear chain with a bend have been calculated as examples allowing a simple analytical representation. Generalization to two- and three-dimensional nanosystems has been developed.

  2. High resolution structural characterisation of laser-induced defect clusters inside diamond

    NASA Astrophysics Data System (ADS)

    Salter, Patrick S.; Booth, Martin J.; Courvoisier, Arnaud; Moran, David A. J.; MacLaren, Donald A.

    2017-08-01

    Laser writing with ultrashort pulses provides a potential route for the manufacture of three-dimensional wires, waveguides, and defects within diamond. We present a transmission electron microscopy study of the intrinsic structure of the laser modifications and reveal a complex distribution of defects. Electron energy loss spectroscopy indicates that the majority of the irradiated region remains as sp3 bonded diamond. Electrically conductive paths are attributed to the formation of multiple nano-scale, sp2-bonded graphitic wires and a network of strain-relieving micro-cracks.

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

    NASA Astrophysics Data System (ADS)

    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.

  4. An analysis of the effect of defect structures on catalytic surfaces by the boundary element technique

    NASA Astrophysics Data System (ADS)

    Peirce, Anthony P.; Rabitz, Herschel

    1988-08-01

    The boundary element (BE) technique is used to analyze the effect of defects on one-dimensional chemically active surfaces. The standard BE algorithm for diffusion is modified to include the effects of bulk desorption by making use of an asymptotic expansion technique to evaluate influences near boundaries and defect sites. An explicit time evolution scheme is proposed to treat the non-linear equations associated with defect sites. The proposed BE algorithm is shown to provide an efficient and convergent algorithm for modelling localized non-linear behavior. Since it exploits the actual Green's function of the linear diffusion-desorption process that takes place on the surface, the BE algorithm is extremely stable. The BE algorithm is applied to a number of interesting physical problems in which non-linear reactions occur at localized defects. The Lotka-Volterra system is considered in which the source, sink and predator-prey interaction terms are distributed at different defect sites in the domain and in which the defects are coupled by diffusion. This example provides a stringent test of the stability of the numerical algorithm. Marginal stability oscillations are analyzed for the Prigogine-Lefever reaction that occurs on a lattice of defects. Dissipative effects are observed for large perturbations to the marginal stability state, and rapid spatial reorganization of uniformly distributed initial perturbations is seen to take place. In another series of examples the effect of defect locations on the balance between desorptive processes on chemically active surfaces is considered. The effect of dynamic pulsing at various time-scales is considered for a one species reactive trapping model. Similar competitive behavior between neighboring defects previously observed for static adsorption levels is shown to persist for dynamic loading of the surface. The analysis of a more complex three species reaction process also provides evidence of competitive behavior between

  5. Multisensor fusion for 3-D defect characterization using wavelet basis function neural networks

    NASA Astrophysics Data System (ADS)

    Lim, Jaein; Udpa, Satish S.; Udpa, Lalita; Afzal, Muhammad

    2001-04-01

    The primary objective of multi-sensor data fusion, which offers both quantitative and qualitative benefits, has the ability to draw inferences that may not be feasible with data from a single sensor alone. In this paper, data from two sets of sensors are fused to estimate the defect profile from magnetic flux leakage (MFL) inspection data. The two sensors measure the axial and circumferential components of the MFL. Data is fused at the signal level. If the flux is oriented axially, the samples of the axial signal are measured along a direction parallel to the flaw, while the circumferential signal is measured in a direction that is perpendicular to the flaw. The two signals are combined as the real and imaginary components of a complex valued signal. Signals from an array of sensors are arranged in contiguous rows to obtain a complex valued image. A boundary extraction algorithm is used to extract the defect areas in the image. Signals from the defect regions are then processed to minimize noise and the effects of lift-off. Finally, a wavelet basis function (WBF) neural network is employed to map the complex valued image appropriately to obtain the geometrical profile of the defect. The feasibility of the approach was evaluated using the data obtained from the MFL inspection of natural gas transmission pipelines. Results show the effectiveness of the approach.

  6. Anatomy of the ventricular septal defect in outflow tract defects: similarities and differences.

    PubMed

    Mostefa-Kara, Meriem; Bonnet, Damien; Belli, Emre; Fadel, Elie; Houyel, Lucile

    2015-03-01

    The study objective was to analyze the anatomy of the ventricular septal defect found in various phenotypes of outflow tract defects. We reviewed 277 heart specimens with isolated outlet ventricular septal defect without subpulmonary stenosis (isolated outlet ventricular septal defect, 19); tetralogy of Fallot (71); tetralogy of Fallot with pulmonary atresia (51); common arterial trunk (54); double outlet right ventricle (65) with subaortic, doubly committed, or subpulmonary ventricular septal defect; and interrupted aortic arch type B (17). Special attention was paid to the rims of the ventricular septal defect viewed from the right ventricular side and the relationships between the tricuspid and aortic valves. The ventricular septal defect was always located in the outlet of the right ventricle, between the 2 limbs of the septal band. There was a fibrous continuity between the tricuspid and aortic valves in 74% of specimens with isolated outlet ventricular septal defect, 66% of specimens with tetralogy of Fallot, 39% of specimens with tetralogy of Fallot with pulmonary atresia, 4.6% of specimens with double outlet right ventricle, 1.8% of specimens with common arterial trunk, and zero of specimens with interrupted aortic arch type B (P < .005). When present, this continuity always involved the anterior tricuspid leaflet. The ventricular septal defect in outflow tract defects is always an outlet ventricular septal defect, cradled between the 2 limbs of the septal band. However, there are some differences regarding the posteroinferior and superior rims of the ventricular septal defect. These differences suggest an anatomic continuum from the isolated outlet ventricular septal defect to the interrupted aortic arch type B rather than distinct physiologic phenotypes, related to various degrees of abnormal rotation of the outflow tract during heart development: minimal in isolated outlet ventricular septal defect; incomplete in tetralogy of Fallot, tetralogy of Fallot

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

    NASA Astrophysics Data System (ADS)

    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.

  8. Softball Complex

    ERIC Educational Resources Information Center

    Ellis, Jim

    1977-01-01

    The Parks and Recreation Department of Montgomery, Alabama, has developed a five-field softball complex as part of a growing community park with facilities for camping, golf, aquatics, tennis, and picnicking. (MJB)

  9. Complex Light

    NASA Astrophysics Data System (ADS)

    Secor, Jeff; Alfano, Robert; Ashrafi, Solyman

    2017-01-01

    The emerging field of complex light-the study and application of custom light beams with tailored intensity, polarization or phase-is a focal point for fundamental breakthroughs in optical science. As this review will show, those advances in fundamental understanding, coupled with the latest developments in complex light generation, are translating into a range of diverse and cross-disciplinary applications that span microscopy, high-data-rate communications, optical trapping and quantum optics. We can expect more twists along the way, too, as researchers seek to manipulate and control the propagation speed of complex light beams, while others push the more exotic possibilities afforded by complex light in quantum-entanglement experiments.

  10. Maternal autoimmune disease and birth defects in the National Birth Defects Prevention Study.

    PubMed

    Howley, Meredith M; Browne, Marilyn L; Van Zutphen, Alissa R; Richardson, Sandra D; Blossom, Sarah J; Broussard, Cheryl S; Carmichael, Suzan L; Druschel, Charlotte M

    2016-11-01

    Little is known about the association between maternal autoimmune disease or its treatment and the risk of birth defects. We examined these associations using data from the National Birth Defects Prevention Study, a multi-site, population-based, case-control study. Analyses included 25,116 case and 9897 unaffected control infants with estimated delivery dates between 1997 and 2009. Information on autoimmune disease, medication use, and other pregnancy exposures was collected by means of telephone interview. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated for birth defects with five or more exposed cases; crude ORs and exact 95% CIs were estimated for birth defects with three to four exposed cases. Autoimmune disease was reported by 373 mothers (279 case and 94 control mothers). The majority of birth defects evaluated were not associated with autoimmune disease; however, a statistically significant association between maternal autoimmune disease and encephalocele was observed (OR, 4.64; 95% CI, 1.95-11.04). Eighty-two mothers with autoimmune disease used an immune modifying/suppressing medication during pregnancy; this was associated with encephalocele (OR, 7.26; 95% CI, 1.37-24.61) and atrial septal defects (OR, 3.01; 95% CI, 1.16-7.80). Our findings suggest maternal autoimmune disease and treatment are not associated with the majority of birth defects, but may be associated with some defects, particularly encephalocele. Given the low prevalence of individual autoimmune diseases and the rare use of specific medications, we were unable to examine associations of specific autoimmune diseases and medications with birth defects. Other studies are needed to confirm these findings. Birth Defects Research (Part A) 106:950-962, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  11. Fluconazole use and birth defects in the National Birth Defects Prevention Study.

    PubMed

    Howley, Meredith M; Carter, Tonia C; Browne, Marilyn L; Romitti, Paul A; Cunniff, Christopher M; Druschel, Charlotte M

    2016-05-01

    Low-dose fluconazole is used commonly to treat vulvovaginal candidiasis, a condition occurring frequently during pregnancy. Conflicting information exists on the association between low-dose fluconazole use among pregnant women and the risk of major birth defects. We used data from the National Birth Defects Prevention Study to examine this association. The National Birth Defects Prevention Study is a multisite, population-based, case-control study that includes pregnancies with estimated delivery dates from 1997 to 2011. Information on fluconazole use in early pregnancy was collected by self-report from 31,645 mothers of birth defect cases and 11,612 mothers of unaffected controls. Adjusted odds ratios and 95% confidence intervals were estimated for birth defects with 5 or more exposed cases; crude odds ratios and exact 95% confidence intervals were estimated for birth defects with 3-4 exposed cases. Of the 43,257 mothers analyzed, 44 case mothers and 6 control mothers reported using fluconazole. Six exposed infants had cleft lip with cleft palate, 4 had an atrial septal defect, and each of the following defects had 3 exposed cases: hypospadias, tetralogy of Fallot, d-transposition of the great arteries, and pulmonary valve stenosis. Fluconazole use was associated with cleft lip with cleft palate (odds ratio = 5.53; confidence interval = 1.68-18.24) and d-transposition of the great arteries (odds ratio = 7.56; confidence interval = 1.22-35.45). The associations between fluconazole and both cleft lip with cleft palate and d-transposition of the great arteries are consistent with earlier published case reports but not recent epidemiologic studies. Despite the larger sample size of the National Birth Defects Prevention Study, fluconazole use was rare. Further investigation is needed in large studies, with particular emphasis on oral clefts and conotruncal heart defects. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Trapping of drops by wetting defects

    PubMed Central

    't Mannetje, Dieter; Ghosh, Somnath; Lagraauw, Rudy; Otten, Simon; Pit, Arjen; Berendsen, Christian; Zeegers, Jos; van den Ende, Dirk; Mugele, Frieder

    2014-01-01

    Controlling the motion of drops on solid surfaces is crucial in many natural phenomena and technological processes including the collection and removal of rain drops, cleaning technology and heat exchangers. Topographic and chemical heterogeneities on solid surfaces give rise to pinning forces that can capture and steer drops in desired directions. Here we determine general physical conditions required for capturing sliding drops on an inclined plane that is equipped with electrically tunable wetting defects. By mapping the drop dynamics on the one-dimensional motion of a point mass, we demonstrate that the trapping process is controlled by two dimensionless parameters, the trapping strength measured in units of the driving force and the ratio between a viscous and an inertial time scale. Complementary experiments involving superhydrophobic surfaces with wetting defects demonstrate the general applicability of the concept. Moreover, we show that electrically tunable defects can be used to guide sliding drops along actively switchable tracks—with potential applications in microfluidics. PMID:24721935

  13. Defect Proliferation in Active Nematic Suspensions

    NASA Astrophysics Data System (ADS)

    Mishra, Prashant; Bowick, Mark J.; Giomi, Luca; Marchetti, M. Cristina

    2014-03-01

    The rich structure of equilibrium nematic suspensions, with their characteristic disclination defects, is modified when active forces come into play. The uniform nematic state is known to be unstable to splay (extensile) or bend (contractile) deformations above a critical activity. At even higher activity the flow becomes oscillatory and eventually turbulent. Using hydrodynamics, we classify the active flow regimes as functions of activity and order parameter friction for both contractile and extensile systems. The turbulent regime is marked by a non-zero steady state density of mobile defect pairs. The defect density itself scales with an ``active Ericksen number,'' defined as the ratio of the rate at which activity is injected into the system to the relaxation rate of orientational deformations. The work at Syracuse University was supported by the NSF on grant DMR-1004789 and by the Syracuse Soft Matter Program.

  14. Reconstruction of Facial Defect Using Deltopectoral Flap.

    PubMed

    Aldelaimi, Tahrir N; Khalil, Afrah A

    2015-11-01

    Reconstruction of the head and neck is a challenge for otolarygology surgeons, maxillofacial surgeons as well as plastic surgeons. Defects caused by the resection and/or trauma should be closed with flaps which match in color, texture and hair bearing characteristics with the face. Deltopectoral flap is a one such flap from chest and neck skin mainly used to cover the facial defects. This study report a patient presenting with tragic Road Traffic Accident (RTA) admitted to maxillofacial surgery department at Ramadi Teaching Hospital, Anbar province, Iraq. An incision, medially based, was done and deltopectoral fascio-cutaneous flap was used for surgical exposure and closure of defects after RTA. There was no major complication. Good aesthetic and functional results were achieved. Deltopectoral flap is an excellent alternative for the reconstruction of head and neck. Harvesting and application of the flap is rapid and safe. Only a single incision is sufficient for dissection and flap elevation.

  15. 48 CFR 1615.407-1 - Rate reduction for defective pricing or defective cost or pricing data.

    Code of Federal Regulations, 2010 CFR

    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...

  16. 48 CFR 1615.407-1 - Rate reduction for defective pricing or defective cost or pricing data.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 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...

  17. 48 CFR 1615.407-1 - Rate reduction for defective pricing or defective cost or pricing data.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 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...

  18. 48 CFR 1615.407-1 - Rate reduction for defective pricing or defective cost or pricing data.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 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...

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

    USDA-ARS?s Scientific Manuscript database

    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...

  20. Angle dependent defect modes in a photonic crystal filter doped by high and low temperature superconductor defects

    NASA Astrophysics Data System (ADS)

    Sreejith K., P.; Mathew, Vincent

    2018-05-01

    We have theoretically investigated the incident angle dependent defect modes in a dual channel photonic crystal filter composed of a high and low temperature superconductor defects. It is observed that the defect mode wavelength can be significantly tuned by incident angle for both polarizations. The angle sensitive defect mode property is of particular application in designing narrow band transmission filter.

  1. Defect studies of nanocrystalline zirconia powders and sintered ceramics

    NASA Astrophysics Data System (ADS)

    Čížek, Jakub; Melikhova, Oksana; Procházka, Ivan; Kuriplach, Jan; Kužel, Radomír; Brauer, Gerhard; Anwand, Wolfgang; Konstantinova, Tatyana E.; Danilenko, Igor A.

    2010-01-01

    The main objective of the present paper is to communicate a study of defects behavior in zirconia-based nanomaterials—pressure-compacted yttria-stabilized zirconia (YSZ) nanopowders with different contents of Y2O3 and ceramics obtained by sintering the YZS nanopowders. In addition, YZS single crystals were also investigated. Positron annihilation techniques including positron lifetime and coincidence Doppler broadening with a conventional positron source and Doppler broadening experiments on a monoenergetic positron beam were involved in this study as the principal tools. These techniques were supplemented with transmission electron microscopy and x-ray diffraction observations. In order to get better support of the experimental data interpretation, the state-of-art theoretical calculations of positron parameters were performed for the perfect ZrO2 lattice and selected defect configurations in the YSZ. Theoretical calculations have indicated that neither the oxygen vacancies nor their neutral complexes with substitutional yttrium atoms are capable of positron trapping. On the other hand, the zirconium vacancies are deep positron traps and obviously are responsible for the saturated positron trapping observed in the YSZ single crystals. In the compacted YSZ nanopowders, a majority of positrons is trapped either in the vacancylike defects situated in the negative space-charge layers along grain boundaries (τ1≈185ps) or in vacancy clusters at intersections of grain boundaries (τ2≈370ps) . The intensity ratio I2/I1 was found to be correlated with the mean grain size d as I2/I1˜d-2 . A small fraction of positrons (≈10%) form positronium in large pores (τ3≈2ns,τ4≈30ns) . A significant grain growth during sintering of the YSZ nanopowders above 1000°C was observed.

  2. Photoresponse in graphene induced by defect engineering

    NASA Astrophysics Data System (ADS)

    Du, Ruxia; Wang, Wenhui; Du, Jianxin; Guo, Xitao; Liu, Er; Bing, Dan; Bai, Jing

    2016-11-01

    We present a photoresponse study on a lateral defect/pristine graphene junction device fabricated by a simple plasma irradiation method. The junction between pristine graphene and plasma-modified graphene was created by controlling the location of Ar+ plasma treatment. We found that a distinct photocurrent was generated at the junction by photocurrent line scanning measurements, and further analysis reveals that the photo-thermoelectric (PTE) effect, instead of the photovoltaic (PV) effect, dominates the photocurrent generation at the interface. Additionally, the obtained results suggest that tuning the defect density could be effective in modulating the optoelectronic performance of junctions in our device.

  3. Surgical management of cosmetic mucogingival defects.

    PubMed

    Dym, Harry; Tagliareni, Jonathan M

    2012-01-01

    Mucogingival conditions are deviations from the normal anatomic relationship between the gingival margin and the mucogingival junction. Mucogingival surgery is plastic surgery designed to correct defects in the gingiva surrounding the teeth. Common mucogingival conditions are recession, absence, or reduction of keratinized tissue, and probing depths extending beyond the mucogingival junction. Surgical techniques used to augment cosmetic mucogingival defects include the free gingival autograft, the subepithelial connective tissue graft, rotational flaps, lateral sliding flaps, coronally repositioned flaps, and the use of acellular dermal matrix grafts. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. Intersecting surface defects and instanton partition functions

    NASA Astrophysics Data System (ADS)

    Pan, Yiwen; Peelaers, Wolfger

    2017-07-01

    We analyze intersecting surface defects inserted in interacting four-dimensional N=2 supersymmetric quantum field theories. We employ the realization of a class of such systems as the infrared fixed points of renormalization group flows from larger theories, triggered by perturbed Seiberg-Witten monopole-like configurations, to compute their partition functions. These results are cast into the form of a partition function of 4d/2d/0d coupled systems. Our computations provide concrete expressions for the instanton partition function in the presence of intersecting defects and we study the corresponding ADHM model.

  5. Counting defects in an instantaneous quench.

    PubMed

    Ibaceta, D; Calzetta, E

    1999-09-01

    We consider the formation of defects in a nonequilibrium second-order phase transition induced by an instantaneous quench to zero temperature in a type II superconductor. We perform a full nonlinear simulation where we follow the evolution in time of the local order parameter field. We determine how far into the phase transition theoretical estimates of the defect density based on the Gaussian approximation yield a reliable prediction for the actual density. We also characterize quantitatively some aspects of the out of equilibrium phase transition.

  6. Intersecting surface defects and instanton partition functions

    DOE PAGES

    Pan, Yiwen; Peelaers, Wolfger

    2017-07-14

    We analyze intersecting surface defects inserted in interacting four-dimensional N = 2 supersymmetric quantum field theories. We employ the realization of a class of such systems as the infrared xed points of renormalization group flows from larger theories, triggered by perturbed Seiberg-Witten monopole-like con gurations, to compute their partition functions. These results are cast into the form of a partition function of 4d/2d/0d coupled systems. In conclusion, our computations provide concrete expressions for the instanton partition function in the presence of intersecting defects and we study the corresponding ADHM model.

  7. [Familial occurrence of acquired heart valve defect].

    PubMed

    Schieche, M

    1975-09-15

    A report is given on a family examination, issuing from 213 persons with an acquired valvular defect for the establishment of further cases on altogether 783 relations of the direct line. In 19 families other 21 patients with an acquired valvular defect were found; this corresponds to a share of 2.7 % of the relations examined and 8.1% of the families affected, respectively. The result repays the expenditure and, apart from this, leads to an essential furthering of the confidence between physician, patient and family as the smallest social unity for prophylaxis, diagnostics, therapy and metaphylaxis of chronic diseases.

  8. Dirac oscillator interacting with a topological defect

    SciTech Connect

    Carvalho, J.; Furtado, C.; Moraes, F.

    In this work we study the interaction problem of a Dirac oscillator with gravitational fields produced by topological defects. The energy levels of the relativistic oscillator in the cosmic string and in the cosmic dislocation space-times are sensible to curvature and torsion associated to these defects and are important evidence of the influence of the topology on this system. In the presence of a localized magnetic field the energy levels acquire a term associated with the Aharonov-Bohm effect. We obtain the eigenfunctions and eigenvalues and see that in the nonrelativistic limit some results known in standard quantum mechanics are reached.

  9. Intersecting surface defects and instanton partition functions

    SciTech Connect

    Pan, Yiwen; Peelaers, Wolfger

    We analyze intersecting surface defects inserted in interacting four-dimensional N = 2 supersymmetric quantum field theories. We employ the realization of a class of such systems as the infrared xed points of renormalization group flows from larger theories, triggered by perturbed Seiberg-Witten monopole-like con gurations, to compute their partition functions. These results are cast into the form of a partition function of 4d/2d/0d coupled systems. In conclusion, our computations provide concrete expressions for the instanton partition function in the presence of intersecting defects and we study the corresponding ADHM model.

  10. Arrhythmias in Patients with Atrial Defects.

    PubMed

    Contractor, Tahmeed; Mandapati, Ravi

    2017-06-01

    Atrial arrhythmias are common in patients with atrial septal defects. A myriad of factors are responsible for these that include remodeling related to the defect and scar created by the repair or closure. An understanding of potential arrhythmias, along with entrainment and high-density activation mapping can result in accurate diagnosis and successful ablation. Atrial fibrillation is being seen increasingly after patent foramen ovale closure and may be the primary etiology of recurrent stroke in these patients. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Two Stage Repair of Composite Craniofacial Defects with Antibiotic Releasing Porous Poly(methyl methacrylate) Space Maintainers and Bone Regeneration

    NASA Astrophysics Data System (ADS)

    Spicer, Patrick

    Craniofacial defects resulting from trauma and resection present many challenges to reconstruction due to the complex structure, combinations of tissues, and environment, with exposure to the oral, skin and nasal mucosal pathogens. Tissue engineering seeks to regenerate the tissues lost in these defects; however, the composite nature and proximity to colonizing bacteria remain difficult to overcome. Additionally, many tissue engineering approaches have further hurdles to overcome in the regulatory process to clinical translation. As such these studies investigated a two stage strategy employing an antibiotic-releasing porous polymethylmethacrylate space maintainer fabricated with materials currently part of products approved or cleared by the United States Food and Drug Administration, expediting the translation to the clinic. This porous space maintainer holds the bone defect open allowing soft tissue to heal around the defect. The space maintainer can then be removed and one regenerated in the defect. These studies investigated the individual components of this strategy. The porous space maintainer showed similar soft tissue healing and response to non-porous space maintainers in a rabbit composite tissue defect. The antibiotic-releasing space maintainers showed release of antibiotics from 1-5 weeks, which could be controlled by loading and fabrication parameters. In vivo, space maintainers releasing a high dose of antibiotics for an extended period of time increased soft tissue healing over burst release space maintainers in an infected composite tissue defect model in a rabbit mandible. Finally, stabilization of bone defects and regeneration could be improved through scaffold structures and delivery of a bone forming growth factor. These studies illustrate the possibility of the two stage strategy for repair of composite tissue defects of the craniofacial complex.

  12. Simulation of laser generated ultrasound with application to defect detection

    NASA Astrophysics Data System (ADS)

    Pantano, A.; Cerniglia, D.

    2008-06-01

    Laser generated ultrasound holds substantial promise for use as a tool for defect detection in remote inspection thanks to its ability to produce frequencies in the MHz range, enabling fine spatial resolution of defects. Despite the potential impact of laser generated ultrasound in many areas of science and industry, robust tools for studying the phenomenon are lacking and thus limit the design and optimization of non-destructive testing and evaluation techniques. The laser generated ultrasound propagation in complex structures is an intricate phenomenon and is extremely hard to analyze. Only simple geometries can be studied analytically. Numerical techniques found in the literature have proved to be limited in their applicability, by the frequencies in the MHz range and very short wavelengths. The objective of this research is to prove that by using an explicit integration rule together with diagonal element mass matrices, instead of the almost universally adopted implicit integration rule to integrate the equations of motion in a dynamic analysis, it is possible to efficiently and accurately solve ultrasound wave propagation problems with frequencies in the MHz range travelling in relatively large bodies. Presented results on NDE testing of rails demonstrate that the proposed FE technique can provide a valuable tool for studying the laser generated ultrasound propagation.

  13. Defect Facilitated Phonon Transport through Kinks in Boron Carbide Nanowires

    DOE PAGES

    Zhang, Qian; Cui, Zhiguang; Wei, Zhiyong; ...

    2017-05-08

    Nanowires of complex morphologies, such as kinked wires, have been recently synthesized and demonstrated for novel devices and applications. However, the effects of these morphologies on thermal transport have not been well studied. Through systematic experimental measurements, we show in this paper that single-crystalline, defect-free kinks in boron carbide nanowires can pose a thermal resistance up to ~30 times larger than that of a straight wire segment of equivalent length. Analysis suggests that this pronounced resistance can be attributed to the combined effects of backscattering of highly focused phonons and required mode conversion at the kink. Interestingly, it is alsomore » found that instead of posing resistance, structural defects in the kink can actually assist phonon transport through the kink and reduce its resistance. Finally, given the common kink-like wire morphology in nanoelectronic devices and required low thermal conductivity for thermoelectric devices, these findings have important implications in precise thermal management of electronic devices and thermoelectrics.« less

  14. Wound Healing Is Defective in Mice Lacking Tetraspanin CD151

    PubMed Central

    Cowin, Allison J.; Adams, Damian; Geary, Sean M.; Wright, Mark D.; Jones, Jonathan C.R.; Ashman, Leonie K.

    2010-01-01

    The tetraspanin CD151 forms complexes in epithelial cell membranes with laminin-binding integrins α6 β4, α3 β1, and α6 β1, and modifies integrin-mediated cell migration in vitro. We demonstrate in this study that CD151 expression is upregulated in a distinct temporal and spatial pattern during wound healing, particularly in the migrating epidermal tongue at the wound edge, suggesting a role for CD151 in keratinocyte migration. We show that healing is significantly impaired in CD151-null mice, with wounds gaping wider at 7 days post-injury. The rate of re-epithelialization of the CD151-null wounds is adversely affected, with significantly less wound area being covered by migrating epidermal cells. Our studies reveal that although laminin levels are similar in wild-type and CD151-null wounds, the organization of the laminin in the basement membrane is impaired. Furthermore, upregulation of α6 and β4 integrin expression is adversely affected in CD151-null mice wounds. In contrast, we find no significant effect of CD151 gene knockout on α3 and β1 integrin expression in wound repair. We suggest that mice lacking the CD151 gene are defective in wound healing, primarily owing to impairment of the re-epithelialization process. This may be due to defective basement membrane formation and epithelial cell adhesion and migration. PMID:16410781

  15. CLOSURE OF LARYNGECTOMY DEFECTS IN THE AGE OF CHEMORADIATION THERAPY

    PubMed Central

    Hanasono, Matthew M.; Lin, Derrick; Wax, Mark K.

    2014-01-01

    The use of chemoradiation therapy in laryngeal cancer has resulted in significant reconstructive challenges. Although reconstruction of salvage laryngectomy defects remains controversial, current literature supports aggressive management of these defects with vascularized tissue, even when there is sufficient pharyngeal tissue present for primary closure. Significant advancement in reconstructive techniques has permitted improved outcomes in patients with advanced disease who require total laryngopharyngectomy or total laryngoglossectomy. Use of enteric and fasciocutaneous flaps result in good patient outcomes. Finally, wound complication rates after salvage surgery approach 60% depending on comorbid conditions such as cardiac insufficiency, hypothyroidism, or extent of previous treatment. Neck dehiscence, great vessel exposure, fistula formation, or cervical skin necrosis results in complex wounds that can often be treated initially with negative pressure dressings followed by definitive reconstruction. The timing of repair and approach to the vessel-depleted neck also present challenges in this patient population. Currently, there is significant institutional bias in the management of the patient with postchemoradiation salvage laryngectomy. Future prospective multi-institutional studies are certainly needed to more clearly define optimal treatment of these difficult patients. PMID:21416549

  16. TorsinA dysfunction causes persistent neuronal nuclear pore defects.

    PubMed

    Pappas, Samuel S; Liang, Chun-Chi; Kim, Sumin; Rivera, CheyAnne O; Dauer, William T

    2018-02-01

    A critical challenge to deciphering the pathophysiology of neurodevelopmental disease is identifying which of the myriad abnormalities that emerge during CNS maturation persist to contribute to long-term brain dysfunction. Childhood-onset dystonia caused by a loss-of-function mutation in the AAA+ protein torsinA exemplifies this challenge. Neurons lacking torsinA develop transient nuclear envelope (NE) malformations during CNS maturation, but no NE defects are described in mature torsinA null neurons. We find that during postnatal CNS maturation torsinA null neurons develop mislocalized and dysfunctional nuclear pore complexes (NPC) that lack NUP358, normally added late in NPC biogenesis. SUN1, a torsinA-related molecule implicated in interphase NPC biogenesis, also exhibits localization abnormalities. Whereas SUN1 and associated nuclear membrane abnormalities resolve in juvenile mice, NPC defects persist into adulthood. These findings support a role for torsinA function in NPC biogenesis during neuronal maturation and implicate altered NPC function in dystonia pathophysiology. © The Author(s) 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. Defect Facilitated Phonon Transport through Kinks in Boron Carbide Nanowires

    SciTech Connect

    Zhang, Qian; Cui, Zhiguang; Wei, Zhiyong

    Nanowires of complex morphologies, such as kinked wires, have been recently synthesized and demonstrated for novel devices and applications. However, the effects of these morphologies on thermal transport have not been well studied. Through systematic experimental measurements, we show in this paper that single-crystalline, defect-free kinks in boron carbide nanowires can pose a thermal resistance up to ~30 times larger than that of a straight wire segment of equivalent length. Analysis suggests that this pronounced resistance can be attributed to the combined effects of backscattering of highly focused phonons and required mode conversion at the kink. Interestingly, it is alsomore » found that instead of posing resistance, structural defects in the kink can actually assist phonon transport through the kink and reduce its resistance. Finally, given the common kink-like wire morphology in nanoelectronic devices and required low thermal conductivity for thermoelectric devices, these findings have important implications in precise thermal management of electronic devices and thermoelectrics.« less

  18. Structural defects caused by swift ions in fluorite single crystals

    NASA Astrophysics Data System (ADS)

    Assylbayev, Ruslan; Lushchik, Aleksandr; Lushchik, Cheslav; Kudryavtseva, Irina; Shablonin, Evgeni; Vasil'chenko, Evgeni; Akilbekov, Abdirash; Zdorovets, Maxim

    2018-01-01

    A comparative study of radiation damage caused by the irradiation of oxygen-free calcium fluoride single crystals with ∼GeV 132Xe or 209Bi heavy ions, 100-keV light hydrogen ions (protons) or X-rays at room temperature has been performed. Optical absorption in a wide spectral region from NIR to VUV (1.5-10.5 eV), its dependence on stepwise preheating of the irradiated CaF2 crystals to a certain temperature as well as thermally stimulated luminescence accompanying the main annealing stages have been analyzed. It is shown that in addition to different F-type aggregates, Ca colloids and trifluorine quasi-molecules, complex and temperature stable structural defects responsible for VUV absorption (in particular, the 9.8 eV band) are induced in CaF2 only after irradiation with swift heavy ions. The origin and tentative creation mechanisms of such defects as well as the features of the used irradiation types are considered.

  19. Remote defect imaging for plate-like structures based on the scanning laser source technique

    NASA Astrophysics Data System (ADS)

    Hayashi, Takahiro; Maeda, Atsuya; Nakao, Shogo

    2018-04-01

    In defect imaging with a scanning laser source technique, the use of a fixed receiver realizes stable measurements of flexural waves generated by laser at multiple rastering points. This study discussed the defect imaging by remote measurements using a laser Doppler vibrometer as a receiver. Narrow-band burst waves were generated by modulating laser pulse trains of a fiber laser to enhance signal to noise ratio in frequency domain. Averaging three images obtained at three different frequencies suppressed spurious distributions due to resonance. The experimental system equipped with these newly-devised means enabled us to visualize defects and adhesive objects in plate-like structures such as a plate with complex geometries and a branch pipe.

  20. Defect States Emerging from a Non-Hermitian Flatband of Photonic Zero Modes

    NASA Astrophysics Data System (ADS)

    Qi, Bingkun; Zhang, Lingxuan; Ge, Li

    2018-03-01

    We show the existence of a flatband consisting of photonic zero modes in a gain and loss modulated lattice system as a result of the underlying non-Hermitian particle-hole symmetry. This general finding explains the previous observation in parity-time symmetric systems where non-Hermitian particle-hole symmetry is hidden. We further discuss the defect states in these systems, whose emergence can be viewed as an unconventional alignment of a pseudospin under the influence of a complex-valued pseudomagnetic field. These defect states also behave as a chain with two types of links, one rigid in a unit cell and one soft between unit cells, as the defect states become increasingly localized with the gain and loss strength.