1,029 research outputs found
Effect of interface states on spin-dependent tunneling in Fe/MgO/Fe tunnel junctions
The electronic structure and spin-dependent tunneling in epitaxial
Fe/MgO/Fe(001) tunnel junctions are studied using first-principles
calculations. For small MgO barrier thickness the minority-spin resonant bands
at the two interfaces make a significant contribution to the tunneling
conductance for the antiparallel magnetization, whereas these bands are, in
practice, mismatched by disorder and/or small applied bias for the parallel
magnetization. This explains the experimentally observed decrease in tunneling
magnetoresistance (TMR) for thin MgO barriers. We predict that a monolayer of
Ag epitaxially deposited at the interface between Fe and MgO suppresses
tunneling through the interface band and may thus be used to enhance the TMR
for thin barriers.Comment: 4 pages, 3 eps figures (2 in color), revtex
Late Gadolinium Enhancement of the right ventricular myocardium: Is it really different from the left ?
It has been suggested that, in late gadolinium enhancement, the signal of right ventricular myocardium is nulled at a shorter inversion time than the left. While we initially made the same observation, we believe that the difference is not real, but results from artifacts
pH-equilibration of human hair: Kinetics and pH-dependence of the partition ratios for H+ â and OHâ -ions based on a Freundlich isotherm
Hair is an insoluble, fibrous, α-keratinous, protein composite material, providing outer coverage, e.g., for mammals. In the context of a wider study on the effects of pH on human hair properties, we investigated the time-dependence of pH-equilibration study across the acid and the basic pH-range, using appropriate pure solutions of hydrochloric acid and sodium hydroxide. The results show that pH-equilibration follows essentially equal 1st-order kinetics across the pH-range. The characteristic process time does not change significantly and is in the range of 2.5â5 h. The analysis enables to determine the equilibrium uptakes of H+- and OHâ -ions. These follow the expected U-shaped path across the pH-range. For both acidic and alkaline conditions, data are well described by two very similar sorption isotherms of the Freundlich-type. In consequence, partition ratios for both ions are highest near neutrality (pH 7: >6000) and drop off strongly towards low and high pHs (<50). Hair is thus a very strong âsinkâ for H+ and OHâ. This observation fundamentally challenges traditional views of limited ion uptake, namely, in the mid-pH-range due to hindered diffusion. It also does not support considerations on special roles of certain pHs, specific groups of amino acids, or morphological components. Our analysis thus suggests that established views of the interaction of hair and pH need to be reconsidered, The Freundlich isotherm approach appears to provide a versatile tool to refine our understanding of the interactions of hair and possibly other keratinous materials (horn, nail, feathers) with acids and bases
The relevance of outsourcing and leagile strategies in performance optimization of an integrated process planning and scheduling
Over the past few years growing global competition has forced the manufacturing industries to upgrade their old production strategies with the modern day approaches. As a result, recent interest has been developed towards finding an appropriate policy that could enable them to compete with others, and facilitate them to emerge as a market winner. Keeping in mind the abovementioned facts, in this paper the authors have proposed an integrated process planning and scheduling model inheriting the salient features of outsourcing, and leagile principles to compete in the existing market scenario. The paper also proposes a model based on leagile principles, where the integrated planning management has been practiced. In the present work a scheduling problem has been considered and overall minimization of makespan has been aimed. The paper shows the relevance of both the strategies in performance enhancement of the industries, in terms of their reduced makespan. The authors have also proposed a new hybrid Enhanced Swift Converging Simulated Annealing (ESCSA) algorithm, to solve the complex real-time scheduling problems. The proposed algorithm inherits the prominent features of the Genetic Algorithm (GA), Simulated Annealing (SA), and the Fuzzy Logic Controller (FLC). The ESCSA algorithm reduces the makespan significantly in less computational time and number of iterations. The efficacy of the proposed algorithm has been shown by comparing the results with GA, SA, Tabu, and hybrid Tabu-SA optimization methods
Harvesting anterior iliac crest or calvarial bone grafts to augment severely resorbed edentulous jaws:a systematic review and meta-analysis of patient-reported outcomes
The aim of this systematic review was to compare patient-reported outcomes after harvesting calvarial or anterior iliac crest bone grafts to repair severe jaw defects and enable implant placement. The MEDLINE, Embase, Cochrane Central Register of Controlled Trials databases, and OpenGrey were searched for studies on patient satisfaction, pain, disturbances in daily functioning, sensory alterations, donor site aesthetics, and complication rates. Of the 1946 articles identified, 43 reporting 40 studies fulfilled the inclusion criteria; the studies were one randomized controlled clinical trial, one retrospective controlled clinical trial, and 23 prospective and 15 retrospective cohort studies. A meta-analysis of two studies (74 patients) showed no difference in satisfaction (mean difference (MD) â 0.13, 95% confidence interval (CI) â 1.17 to 0.92; P = 0.813) or postoperative pain (directly postoperative: MD â2.32, 95% CI â5.20 to 0.55, P = 0.113; late postoperative: MD â0.01, 95% CI â0.14 to 0.11, P = 0.825) between donor sites. However, the level of evidence is limited, due to the retrospective, non-randomized design of one study. Postoperative gait disturbances were highly prevalent among the anterior iliac crest patients (28â100% after 1 week). The incidence rates of sensory disturbances and other complications were low, and the donor site aesthetic outcomes were favourable for both graft types. To conclude, harvesting bone grafts from the calvarium or anterior iliac crest to augment the severely resorbed edentulous jaw results in similar patient satisfaction. However, the findings for postoperative pain and disturbances in daily living suggest a trend in favour of calvarial bone grafts if harvested using an adjusted technique
Lowland Rice Nutrient Responses for the Guinea and Sudan Savannas of Nigeria
Copyright © 2018 by the American Society of Agronomy
This is an open access article
doi:10.2134/agronj2017.08.046
Lowland Rice Nutrient Responses for the Guinea and Sudan Savannas of Nigeria
Yield response of irrigated lowland rice (Oryza sativa L.) to nutrient application was determined to improve the information base for fertilizer use in the Sudan and Southern Guinea Savannas of Nigeria. Economically optimal rates (EOR) and agronomic efficiency (AE) were determined. Five N levels and four levels each P, K, and Zn were evaluated with two varieties at two locations. Nitrogen effects varied by variety and location but mean paddy yield with 0 kg haâ1 N was 3.4 Mg haâ1 and was increased by 1.3 Mg haâ1 with 40 kg haâ1 N. The mean EOR of N with fertilizer use cost to paddy price ratios (CP) of 2 to 6 were 56 to 38 kg haâ1 N, respectively. Yield increases with P, K and Zn application were infrequent. Paddy yield was increased in one of four cases with up to 1.5 kg haâ1 Zn. There were no paddy yield increases but some decreases with application of Mg-S-B in addition to N-P-K-Zn. The overall AE of N at EOR with a CP of 4 was 25.3 kg kgâ1. The profit potential of N application was greater for Faro 44 compared with Faro 52 at both locations. Financially constrained farmers who opt to apply N at 50 compared with 100% EOR when CP was 4 can expect 16% less yield increase but 67% higher AE and value to cost ratio. Application of fertilizer N, maybe with P at Kadawa, can be highly profitable for irrigated lowland rice in these agroecological zones
A spoonful of Lâfucoseâan efficient therapy for GFUSâCDG, a new glycosylation disorder
Abstract Congenital disorders of glycosylation are a genetically and phenotypically heterogeneous family of diseases affecting the coâ and posttranslational modification of proteins. Using exome sequencing, we detected biallelic variants in GFUS (NM_003313.4) c.[632G>A];[659C>T] (p.[Gly211Glu];[Ser220Leu]) in a patient presenting with global developmental delay, mild coarse facial features and faltering growth. GFUS encodes GDPâLâfucose synthase, the terminal enzyme in de novo synthesis of GDPâLâfucose, required for fucosylation of Nâ and Oâglycans. We found reduced GFUS protein and decreased GDPâLâfucose levels leading to a general hypofucosylation determined in patient's glycoproteins in serum, leukocytes, thrombocytes and fibroblasts. Complementation of patient fibroblasts with wildâtype GFUS cDNA restored fucosylation. Making use of the GDPâLâfucose salvage pathway, oral fucose supplementation normalized fucosylation of proteins within 4Â weeks as measured in serum and leukocytes. During the followâup of 19Â months, a moderate improvement of growth was seen, as well as a clear improvement of cognitive skills as measured by the Kaufmann ABC and the Nijmegen Pediatric CDG Rating Scale. In conclusion, GFUSâCDG is a new glycosylation disorder for which oral Lâfucose supplementation is promising
The nonlinear time-dependent response of isotactic polypropylene
Tensile creep tests, tensile relaxation tests and a tensile test with a
constant rate of strain are performed on injection-molded isotactic
polypropylene at room temperature in the vicinity of the yield point. A
constitutive model is derived for the time-dependent behavior of
semi-crystalline polymers. A polymer is treated as an equivalent network of
chains bridged by permanent junctions. The network is modelled as an ensemble
of passive meso-regions (with affine nodes) and active meso-domains (where
junctions slip with respect to their positions in the bulk medium with various
rates). The distribution of activation energies for sliding in active
meso-regions is described by a random energy model. Adjustable parameters in
the stress--strain relations are found by fitting experimental data. It is
demonstrated that the concentration of active meso-domains monotonically grows
with strain, whereas the average potential energy for sliding of junctions and
the standard deviation of activation energies suffer substantial drops at the
yield point. With reference to the concept of dual population of crystalline
lamellae, these changes in material parameters are attributed to transition
from breakage of subsidiary (thin) lamellae in the sub-yield region to
fragmentation of primary (thick) lamellae in the post-yield region of
deformation.Comment: 29 pages, 12 figure
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