Values Of C1 Research Articles

Optimization and stability of the contrast transfer function in aberration-corrected electron microscopy

The Contrast Transfer Function (CTF) describes the manner in which the electron microscope modifies the object exit wave function as a result of objective lens aberrations. For optimum resolution in C₃-corrected microscopes it is well established that a small negative value of C₃, offset by positive values of C₅ and defocus C₁ results in the most optimal instrument resolution, and optimization of the CTF has been the subject of several studies. Here we describe a simple design procedure for the CTF that results in a most even transfer of information below the resolution limit. We address not only the resolution of the instrument, but also the stability of the CTF in the presence of small disturbances in C₁ and C₃. We show that resolution can be traded for stability in a rational and transparent fashion. These topics are discussed quantitatively for both weak-phase and strong-phase (or amplitude) objects. The results apply equally to instruments at high electron energy (TEM) and at very low electron energy (LEEM), as the basic optical properties of the imaging lenses are essentially identical.

Pharmacokinetics of tacrolimus according to body composition in recipients of kidney transplants

BackgroundCurrently, the dosage of tacrolimus used after transplantation is based on the patient's body weight. However, there is a low correlation between body weight and body composition in kidney transplant recipients. In this study, we evaluate the pharmacokinetics of tacrolimus according to body composition in 18 Korean kidney transplant recipients with stable graft function. MethodsBody composition parameters were calculated using bioelectrical impedance analysis. Pharmacokinetic profiles were determined 0, 1, 2, 3, and 4 hours after treatment with tacrolimus and were compared between high- and low-level median body composition groups. The values of C0, C1, C2, C3, and C4 were used in determining an abbreviated area under the curve (AUC) for tacrolimus. ResultsThe mean body mass index (BMI) and body composition values were as follows: BMI, 24.3kg/m2; lean mass, 49.8kg; and fat mass, 17.4kg. There were no statistical differences in pharmacokinetic profiles between groups with different BMIs. However, the C0 and C4 in the high-fat group were significantly elevated compared with those of the low-fat group (P=0.024 and 0.031, respectively). Furthermore, the C0, C2, C3, and C4 and the AUC were significantly different between the two lean mass groups (P=0.007, 0.038, 0.047, 0.015, and 0.015, respectively). Other variables, such as waist circumference and arm muscle circumference, did not differentiate between the pharmacokinetic profiles of tacrolimus. ConclusionTaken together, these data suggest that tacrolimus dose monitoring based on body composition may provide adequate dosage leading to favorable long-term outcomes.

Estimation of Bulk modulus and microhardness of tetrahedral semiconductors

A general empirical formula was found for calculating of bulk modulus (B) and microhardness (H) from electronegativity and principal quantum number of II-VI, III-V semiconductors. Constant C1, appearing the in the expression of bulk modulus and constants C2 and C3, appearing in the expression of microhardness and the exponent M have following values respectively The numerical values of C1,C2, C3 and M are respectively 206.6, 8.234, 1.291, -1.10 for II-VI 72.4, 31.87, 7.592, -0.95 for III-V semiconductors. Both electro-negativity and principal quantum number can effectively reflect on the chemical bonding behaviour of constituent atoms in these semiconductors. The calculated values of bulk modulus and microhardness are in good agreement with the reported values in the literature. Present study helps in designing novel semiconductor materials, and to further explore the mechanical properties of these semiconductors.

Multifractal analysis of 1-min summer rainfall time series from a monsoonal watershed in eastern China

Multifractal analysis can provide parameters associated with different scales of rainfall, which may be useful for setting up parsimonious downscaling models of rainfall, or for revealing climate-specific properties. Time series of rain rate with 1-min resolution collected from ten stations over a monsoon watershed in eastern China were used to study the multifractal properties. The power spectra estimated by fast Fourier transform (FFT) and discrete Haar wavelet transform (DWT) showed three scaling regimes: the sub-hourly scaling regime with β ≈ 1.2, the scaling regime from 1 h to 1 day with β close to 0.6, and the low-frequency spectra plateau with β ≈ 0.1. From the hyperbolic tails of exceeding probability distributions, the estimated values of parameter qc are in 2–2.5, which were consistent with the critical order of K(q) curves. The statistical moments display two main scaling regimes: the high-frequency regime from 3 min to 5 days and the scaling regime beyond 5 days. The scales of 5–10 days seem a transitional regime. The reason that the regimes, revealed by the power spectra, disagree with the statistical moments may be that both FFT and DWT power spectra have limited abilities of analyzing low-frequency scaling but are sensitive to the properties in high-frequency scales. The H values estimated for the regime of sub-hourly scales are larger than 0.4, and the values for the regime 1 h–1 day are close to 0.1. For the low-frequency scales beyond 1 day, negative H is obtained by DWT power spectra. The parameters of universal multifractal models were also estimated. The values of α for the scaling range of 1 min–5 days are 0.486 ± 0.047, and for the low-frequency scaling range, its values are 0.808 ± 0.323. For the high- and low-frequency scaling ranges, the values of C1 are 0.5 and 0.169, respectively, which is different from the values for daily rainfall series collected at the same rain gages.

Perturbation Theory of Polymer Chains Revisited, 2—Intermolecular Excluded Volume of Random and Self‐Avoiding Walks

AbstractThe intermolecular compatibility of 107–108 independent pair configurations of linear chains (chain length 64 ≤ N ≤ 8192) with and without intramolecular interaction on various lattices is checked and the intermolecular excluded volume u evaluated. From the (average) number of possible i‐tuples of overlaps in the pair configurations the parameters Ck of the perturbation theory are calculated. Differences between the various lattice types at finite N vanish completely for N → ∞. While the theoretical values of C1 and C2 were recovered within very narrow limits for chains without intramolecular interaction, markedly higher figures apply to self‐avoiding walks. The excluded volume u itself and higher Ck parameters are called upon to test several classical and renormalized perturbation theories.magnified image

Viscoelastic properties and determination of free volume fraction of multi-walled carbon nanotube/epoxy composite using dynamic mechanical thermal analysis

Various weight fractions of multi-walled carbon nanotubes (MWNTs) were added to the epoxy as reinforcement to fabricate MWNT/epoxy nanocomposites by using ultrasonication and cast molding method. Dilatometeric measurements and Dynamic mechanical thermal analysis (DMTA) were used to determine the William–Landel–Ferry (WLF) constants and the effect of MWNT on viscoelastic behavior of nanocomposites in the glass transition region respectively. The results showed that addition of nanotubes to epoxy had significant effect on the viscoelastic properties. However, use of 0.5wt.% increased the viscoelastic properties more significantly. The WLF constants C1 and C2 were affected by MWNT amount. They seem to be interrelated as C2/C1=3.21–6.27K. It explains a relationship between the free volume fraction (fg) at glass transition temperature (Tg) and the thermal expansion coefficient (CTE). The relationship found between the experimental values of C1, C2 and Δα, clearly disagrees with the classical free volume interpretation of the WLF relationship.

The Impact of Fabric Structure on the Heather Effect of Fabric Woven by Warp and Weft with Different Colors

This article discusses the impact of fabric structure on the heather effect of fabric woven by warp and weft with different colors. The yarns with different Lightness(L), Chroma(C) and hue angle (h) are respectively used as warp and weft, and a series of eight satin weaves are attained by strengthening weave points with interval-by-point approach, and taken as test samples. L1, C1 and h1 of each sample are measured by Optoelectronic integration color measurement instrument, and make a comparison with the theoretical values of L0, C0 and h0, which are calculated by two-color mixing principle of CIE standard Chromaticity. The result shows that: the relationship between fabric color and the percentage of color threads is in accordance with Glassman principle. However, the improvement in Lightness is slightly, the decrease in Chroma is significantly, and the change in hue angle is negligible. The more severe the degree of thread flexion is, the more obvious impact on heather effect.

Factors That Affect Concentrations of Cyclosporine During the Induction Period of Kidney Transplantation: Multivariate Analysis

ObjectiveThe pharmacokinetics of cyclosporine (CsA) depend on numerous factors over the transplantation course. The aim of this study was to evaluate the impact of several clinical variables on CsA concentrations during the induction period after kidney transplantation. MethodsPotential variables were contrasted with CsA concentrations at 2 hours postdose (C2) and with the area under the concentration curve of CsA (AUC) at days 3 and 10 after transplantation. Evaluated variables were: recipient age, gender, body mass index (BMI), type/duration of previous dialysis, pretransplant serum creatinine (sCr), donor type, CsA dose, cold ischemia time, reduction of sCr, and use of other immunosuppressive drugs. ResultsThis series included 112 patients who displayed an average age of 43 ± 13 years, including 62 men and 31 recipients of living donor organs. The induction dose of CsA was 8.36 ± 1.53 mg/kg. On day 3, the C2 was related to the reduction of sCr (P = 0.034) and to the BMI (P = 0.033). There was an inverse correlation with pretransplant sCr (P = 0.012). The AUC correlated with BMI (P = 0.027) and living donor category (P = .002). Patients receiving rapamycin or a locally procured kidney showed a trend toward higher AUC values. On day 10, the CsA dose and use of rapamycin showed a trend to higher values of C2; the AUC was related to the CsA dose (P = .034). None of the other variables showed significant effects. Analysis between variables showed that time on dialysis correlated with the pretransplant sCr (P = .002) and that the CsA dose was negatively associated with BMI (P = .009). ConclusionPretransplant sCr, BMI, living donor kidney category, better functional recovery, and the dose of CsA were predictors of CsA concentrations of clinical interest during this induction period. The effect of BMI was not related to higher doses of CsA.

Lipid Damage Inhibition in Hake by Active Packaging Film with Natural Antioxidants

The capacity of the natural antioxidant to retard oxidation of polyunsaturated fatty acids in hake (Merluccius merluccius) muscle was investigated. Hake fillets were packaged in low‐density polyethylene with the natural antioxidant (sample C1 = 7 mg/dm2 film and sample C2 = 24 mg/dm2 film) or without the antioxidant (control sample) and frozen for 12 months at −20°C. The results confirm the efficacy of an active packaging with a natural antioxidant derived from barley husks to slow the progress of lipid hydrolysis and increase oxidative stability in hake muscle. Determination of peroxide value, conjugated dienes, free fatty acids, thiobarbituric acid reactive substances (TBARS) and anisidine value (AV) proved suitable for studying lipid hydrolysis and primary and secondary lipid oxidation over time. After 6 months of frozen storage, the TBARS levels were lower in hake packed with low‐density polyethylene with the natural antioxidant (C1 and C2) than in the control sample; at month 12, the TBARS values of C1 and C2 were lower (16 and 21%, respectively) than the control samples. AVs observed in samples C1 and C2 at month 9 were lower than those observed in the control sample at month 12. Copyright © 2011 John Wiley & Sons, Ltd.

Electron Beam Radiolysis of Diethyl Phthalate in Aqueous Solutions

Abstract Electron beam radiolysis experiments were undertaken to gain insights into the kinetic mechanisms of diethyl phthalate (DEP) degradation in aqueous solutions. DEP degradation was found to follow pseudo-first-order kinetics. The pseudo-first-order rate constant decayed exponentially with DEP initial concentrations (C0), whereas G values of DEP and C0 followed linear relationship. Addition of sodium carbonate to irradiated DEP solutions reduced DEP decomposition. H2O2 was not favorable for removal of DEP. An effective degradation was achieved in both N2O-saturated and t-BuOH–containing N2-saturated DEP solutions. High removals (>99%) were achieved at 15 kGy without these radical scavengers. Radical scavenging tests indicated that both •OH and e−aq played significant roles in DEP radiolysis. Several intermediates such as monoethyl phthalate, phthalate acid, and short-chain aliphatic carboxylic acids were formed from DEP radiolytic degradation. Finally, DEP was completely mineralized when the absorbe...

Study on the Surface Color Mixing Effect of Fabric with Different Colors of Warp and Weft

The fabrics made of different color values of Lightness (L), Chromaticity (C) and hue angle (h) of warp and weft silks were designed to testify color mixing. According to Glassman’s two-color adding and mixing principle, theoretical values of L0, C0 and h0 for all yarns were calculated. After all yarns were weaved, L1, C1 and h1’s value of each fabric were measured by ultrascan PRO of Optoelectronic integration color measurement instrument. The differences between measured and theoretical values expressed by ΔL, ΔC and Δh were calculated. ΔL, ΔC and Δh characteristics were analyzed and the relationship between ΔL, ΔC and Δh and the colors of warp and weft were discussed. The effects of the relative portion of warp and weft silks, the collection and distribution of interweave points, the uniformity of organized points’ distribution on color mixing based on the measured and theoretical values of fabric were further investigated.

ESR dating of calcrete nodules from Bala, Ankara (Turkey): Preliminary results

The age of two calcrete nodules (C1 and C2) from the Bala section in the region of Ankara, Turkey, is determined by the Electron Spin Resonance (ESR) method. Three radiation-induced ESR signals at g=2.0056 (A signal), g=2.0006 (C signal) and g=2.0038 (broad signal, BL) were observed. The broad signal (BL) intensity was used as a dating signal. The properties of this dating signal are described in this manuscript. The calcrete nodules were irradiated with a (60)Co gamma source and measured with an ESR spectrometer (X-band) to obtain the signal intensity vs. dose curve and fitted well with the single exponential saturation functions. Based on this model, accumulated dose (D(E)) values for dating are obtained using the multiple-aliquot additive dose method. The D(E) values of C1 and C2 calcretes are 1880±207 and 671±67 Gy, respectively. The ESR ages of the two calcrete samples are obtained by assessing the annual dose rate (D) from the content of (238)U, (232)Th and K(2)O determined by wavelength dispersive X-ray fluorescence (XRF) spectrometry. The results are 761±120 and 419±64 ka, respectively, falling into the Middle Pleistocene Epoch in the geological time scale in agreement with the positions of the stratigraphical record.

Microbial Indices Related to Soil Carbon as Affected by Management Practices in Arid Forest and Agricultural Ecosystems

A study was conducted to investigate how management affects soil carbon (C) pools, mineralization kinetics, and related microbiological properties. Soils were sampled from two sites in central Iran. At the Lordegan forest (LOR) site, soil under an oak forest was compared with its adjacent deforested counterpart. At the Fozveh Research Station (FRS) site, adjacent fields under alfalfa and tall fescue cropping were compared. At the LOR site, soil organic C (SOC), total nitrogen (TN), microbial biomass C (MBC), β-glucosidase activity (βG), and potentially mineralizable C (C0) were significantly greater in the forest than in the deforested counterpart. At the FRS site, the soil cropped to alfalfa showed significantly greater values of SOC, TN, MBC, βG, and C0 than that cropped to tall fescue. Overall, soil biodegradable C pools and related processes are largely affected by management practices in the semiarid to arid environments, confirming the role of management as a significant driver of soil C change.

Uplift Capacity of Axially Loaded Piles in Clays

The present study aims at determining the uplift capacity of axially loaded piles in clays whose undrained cohesion increases linearly with depth. With the application of the axisymmetric static limit analysis approach, proposed recently by the writers, the variation of the nondimensional uplift factors with respect to changes in the embedment ratio (H/B) has been obtained for several rates of increase of soil cohesion with depth defined in terms of a nondimensional factor m for given values of soil cohesion (c0) along the ground surface and diameter (B) of pile. The uplift resistance has been evaluated in the form of the uplift factors, Fcb and Fct due to the components of the shaft resistance and the total resistance, respectively. For the given values of c0 and B, the magnitude of the uplift resistance increases continuously with an increase in the value of m. Furthermore, the Fcb values are found to remain unaffected with the variation in the shaft adhesion, whereas, the Fct values increase continuously with an increase in the adhesion factor of the pile shaft.

Numerical modelling for the interpretation of a laboratory mock-up experiment of bentonite/granite interface

Performance assessment of a deep geological repository requires understanding diffusion and determining diffusion parameters under real conditions because diffusion is a key transport mechanism in hosting geological formation. FEBEX (Full-scale Engineered Barrier Experiment) is a demonstration and research project dealing with the bentonite engineered barrier designed for sealing and containment of the high-level radioactive waste repository. To support field investigations of FEBEX in situ test, a large–scale laboratory mock-up experiment (MUE) is being performed at CIEMAT facilities to study tracer migration at the bentonite/granite interface. Numerical models of MUE are presented here for HTO, 36Cl- and 137Cs+. Experiments are modeled with 2-D axi-symmetric finite element grids and are solved with CORE2D V4. Model results indicate that numerical solutions with reference parameters reproduce measured data for HTO and 36Cl- but show large discrepancies for 137Cs+. Relevant diffusion and retention parameters are identified by sensitivity analysis for tracer concentrations in borehole, bentonite and granite, respectively. Interpretation of 137Cs+ data measured in the tracer chamber is perfomed by taking into account the uncertainties in initial activity C0 and initial time t0. Optimum values of C0 and t0 are obtained. The best fit is obtained with De-filter equal to 2.03.10-10 m2/s and Kd-bentonite equal to 5m3.Kg-1.

Re-use of incinerated agro-industrial waste as pozzolanic addition. Comparison with spanish silica fume

This study attempted to determine the viability of using incinerated agro-industrial waste, ashes C1 and C2, as possible artificial pozzolanic additions in traditional and highperformance concretes and mortars, mainly, and for this reason, a comparative study was likewise conducted with Spanish silica fume (HS). The conclusion drawn from the findings was that the two ashes used could be regarded to be centainly, silicic artificial pozzolanic additions but only C2, which had a higher SiO2 content, could be regarded to be a “microsilica”, however, because its loss on ignition, L.O.I., fell within the acceptable range of variability. In contrast, C1 could not be so regarded because its L.O.I. was too high, despite its higher reactive silica SiO 2 r- content. For this reason, ash C1 had to be ruled out for any of the proposed uses, even though in terms of chemical and sulfatic characterization it was closer to HS than C2. By contrast, the mechanical strength values of C2 and HS were comparable, making the former initially acceptable for any of such uses. Finally, it has also been justified that, adoption of any method of trial to determine potential resistance to the sulfates of the Portland cements with calcareous filler lacks of sense.

Application of grinding kinetics analysis of inorganic powders by a stirred ball mill

The need for ultra fine particles has been increasing in the preparation field of raw powders such as fine ceramics and high functional products. A series of wet grinding experiments were carried out on inorganic powders such as calcite, pyrophyllite and talc by a stirred ball mill. The grinding rate constant K’ in the equation of grinding kinetics was examined based on the grinding kinetics analysis as the same type of function of a previous paper on a vertical type planetary ball mill. The experimental particle size distribution of the ground products was obtained in various grinding conditions. The grinding rate constants K and K’ were expressed by empirical equation involving experimental conditions by a stirred ball mill. The empirical equation on the grinding rate constant was expressed in terms of a function involving the ball diameter of grinding balls, the median diameter of feed material, and Bond’s work index of material, in the experimental conditions. The values of empirical constants C1 and C2 were 21.13 and 0.0109 on K, while C1 and C2 were 120.99 and 0.0192 on K′, respectively. And the particle size distribution of ground products of each test material for a given grinding time was found to be expressing the selection function (the specific rate of breakage) which was obtained from the grinding kinetics analysis. In this study, the grinding rate change on calcite and pyrophyllite was similar at the same experimental operation condition. However, in the case of talc, it was observed that the grinding rate was not increased compared with other samples.

Crossing numbers of imbalanced graphs

AbstractThe crossing number, cr(G), of a graph G is the least number of crossing points in any drawing of G in the plane. According to the Crossing Lemma of M. Ajtai, V. Chvátal, M. Newborn, E. Szemerédi, Theory and Practice of Combinatorics, North‐Holland, Amsterdam, New York, 1982, pp. 9–12 and F. T. Leighton, Complexity Issues in VLSI, MIT Press, Cambridge, 1983, the crossing number of any graph with n vertices and e>4n edges is at least constant times e3/n2. Apart from the value of the constant, this bound cannot be improved. We establish some stronger lower bounds under the assumption that the distribution of the degrees of the vertices is irregular. In particular, we show that if the degrees of the vertices are d1⩾d2⩾···⩾dn, then the crossing number satisfies with , and that this bound is tight apart from the values of the constants c1, c2>0. Some applications are also presented. © 2009 Wiley Periodicals, Inc. J Graph Theory 64: 12–21, 2010

Eigenfunctions of Five-Qubit X X Chain and Ground State Concurrence

Use Jordan–Wigner transformation the eigenstates and eigenenergies of five qubits XX chain including external magnetic field are obtained. The concurrences C0,1 and C0,2 of ground state are obtained. For the ferromagnetic, when [, the values of C0,1 and C0,2 are the same. The C0,2 is easily broken by temperature.

Cervical arthroplasty with Discocerv™ “Cervidisc Evolution” surgical procedure and clinical experience 9 years after the first implantation of the first generation

Long time considered as gold standard in the surgical treatment of the cervical disc disease, anterior discectomy and fusion is, however, associated with an important rate of complications and low quality of life levels, especially in young and active populations. As literature emphasized a correlation between fusion (and the resulting suppression of motion) and adjacent segment degeneration, motion-preserving techniques have been imagined; most of them involve cervical disc prostheses that are under clinical and biomechanical evaluation. Various materials and designs are proposed, with the common point that motion axis is located downwards (with regard to the prosthesis), thus allowing not only a physiologicalmotion in a sagittal plane but also some possible mechanical conflicts between unci and the upper vertebra. Uncus resection may solve the conflict, however, with a great risk of postoperative ossification of bone spurs. For a prosthesis whose motion axis is located upwards, motion in frontal plane is physiological, avoiding the aforementioned mechanical conflict and the need for uncus resection. However, the movements in a sagittal plane may be altered, so we studied such a concept of prosthesis from a clinical and biomechanical point of view. The population consisted in 36 patients who underwent cervical arthroplasty with Discocerv™ “Cervidisc Evolution” for cervical degenerative diseases without instability. Among this group, 21 (8 men, 13 women, mean age: 49 ± 9 years) patients reached the 12-month follow-up. The following data were analyzed — (A) clinical: surgery data, complications, return to work, pain (VAS), function (NDI) and overall outcome (Odom’s criteria); (B) radiological: flexion-extension motion, mean centers of rotation, local and C1–C7 lordosis, signs of degeneration or implant migration. Surgery duration was of 65 ± 15 min and the average hospital stay of 4 days. There were one case of per-operative minor (important bleeding) and three cases of postoperative complications (unrelated to the prosthesis). Twelve months after surgery, an important cervical and radicular pain relief was underlined by postoperative values of respectively 22.6 and 20.3 versus 69.1 and 65.3 observed before surgery. Functional disability diminished from 55.4/100 before surgery to 18.7/100 at 1-year follow-up and 83% of patients declared high levels of satisfaction. These findings are in agreement with Odom’s criteria showing 76% of excellent and 24% of good results, 12 months after surgery, and with the good return to work rate (83% of patients resumed their previous activities within 6 months). Radiological analysis showed preserved motion for the treated level (average: 9.2 ± 4°) and adjacent ones at 12 months, with normal centers of rotation in 64% of cases (in all postoperative examinations) and altered but stable in 36% of cases, where motion axis was located more on the superior plate of the prosthesis. A statistically significant difference between pre- and postoperative values of local lordosis showed a restoration of sagittal alignment. Moreover the absence of a significant postoperative evolution as well as the statistically significant differences between long-term post-and preoperative values of C1–C7 lordosis confirmed this progressive realignment. The findings of this ongoing prospective study highlighted encouraging preliminary results suggesting the efficacy of the device in symptoms relief and motion preservation. Nevertheless, they need to be validated by the long-term results, which will clearly show if the device is able to maintain motion while preventing adjacent segment disease.