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Deviation Values (deviation + value)
Kinds of Deviation Values Selected AbstractsStructural consequences of hen egg-white lysozyme orthorhombic crystal growth in a high magnetic field: validation of X-ray diffraction intensity, conformational energy searching and quantitative analysis of B factors and mosaicityACTA CRYSTALLOGRAPHICA SECTION D, Issue 3 2005Shinya Saijo A novel method has been developed to improve protein-crystal perfection during crystallization in a high magnetic field and structural studies have been undertaken. The three-dimensional structure of orthorhombic hen egg-white (HEW) lysozyme crystals grown in a homogeneous and static magnetic field of 10,T has been determined and refined to a resolution of 1.13,Å and an R factor of 17.0%. The 10,T crystals belonged to space group P212121, with unit-cell parameters a = 56.54,(3), b = 73.86,(6), c = 30.50,(2),Å and one molecule per asymmetric unit. A comparison of the structures of the 0,T and 10,T crystals has been carried out. The magnitude of the structural changes, with a root-mean-square deviation value of 0.75,Å for the positions of all protein atoms, is similar to that observed when an identical protein structure is resolved in two different crystalline lattices. The structures remain similar, with the exception of a few residues e.g. Arg68, Arg73, Arg128 and Gln121. The shifts of the arginine residues result in very significant structural fluctuations, which can have large effects on a protein's crystallization properties. The high magnetic field contributed to an improvement in diffraction intensity by (i) the displacement of the charged side chains of Arg68 and Arg73 in the flexible loop and of Arg128 at the C-terminus and (ii) the removal of the alternate conformations of the charged side chains of Arg21, Lys97 or Arg114. The improvement in crystal perfection might arise from the magnetic effect on molecular orientation without structural change and differences in molecular interactions. X-ray diffraction and molecular-modelling studies of lysozyme crystals grown in a 10,T field have indicated that the field contributes to the stability of the dihedral angle. The average difference in conformational energy has a value of ,578,kJ,mol,1 per charged residue in favour of the crystal grown in the magnetic field. For most protein atoms, the average B factor in the 10,T crystal shows an improvement of 1.8,Å2 over that for the 0,T control; subsequently, the difference in diffraction intensity between the 10,T and 0,T crystals corresponds to an increase of 22.6% at the resolution limit. The mosaicity of the 10,T crystal was better than that of the 0,T crystal. More highly isotropic values of 0.0065, 0.0049 and 0.0048° were recorded along the a, b and c axes, respectively. Anisotropic mosaicity analysis indicated that crystal growth is most perfect in the direction that corresponds to the favoured growth direction of the crystal, and that the crystal grown in the magnetic field had domains that were three times the volume of those of the control crystal. Overall, the magnetic field has improved the quality of these crystals and the diffracted intensity has increased significantly with the magnetic field, leading to a higher resolution. [source] Effects of dietary boron on cervical cytopathology and on micronucleus frequency in exfoliated buccal cellsENVIRONMENTAL TOXICOLOGY, Issue 1 2007Mehmet Korkmaz Abstract Recent evidence indicates that boron and borates may have anticarcinogenic properties. In this study, we have investigated the incidence of adverse cytological findings in cervical smears and the micronucleus (MN) frequency in women living in boron-rich and boron-poor regions. Cervical smears were prepared from 1059 women with low socioeconomic status; 472 of the women lived in relatively boron-rich rural areas, while 587 lived in relatively boron-poor regions. The average and standard deviation values for the age of the women screened with the cervical Pap smear test were 41.55 ± 8.38. The mean dietary intake of boron was 8.41 mg/day for women from the boron-rich regions, and 1.26 mg/day for women living in the boron-poor regions (P < 0.0001). Women from the boron-rich regions had no cytopathological indications of cervical cancer, while there were cytopathological findings for 15 women from the boron-poor areas (,2 = 10.473, P < 0.05). Sixty women, 30 from each region, were chosen for evaluating MN frequencies in exfoliated buccal cells. MN frequencies for women from the boron-rich and boron-poor regions were not significantly different (t = ,0.294, P > 0.05). Also, there were no significant correlations between age and MN frequency for women from both the boron-rich (r = 0.133, P = 0.48, P > 0.05) and boron-poor (r = ,0.033, P = 0.861, P > 0.05) regions. The results suggest that ingestion of boron in the drinking water decreases the incidence of cervical cancer-related histopathological findings. There was no correlation between the pathological findings from the cervical smears and buccal cell MN frequency suggesting that the two study populations were exposed equally to gentotoxic agents. Nonetheless, cervical cancer-related histopathological findings should be validated by other researchers. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 17,25, 2007. [source] Hyperspectral NIR image regression part II: dataset preprocessing diagnosticsJOURNAL OF CHEMOMETRICS, Issue 3-4 2006James Burger Abstract When known reference values such as concentrations are available, the spectra from near infrared (NIR) hyperspectral images can be used for building regression models. The sets of spectra must be corrected for errors, transformed to reflectance or absorbance values, and trimmed of bad pixel outliers in order to build robust models and minimize prediction errors. Calibration models can be computed from small (<100) sets of spectra, where each spectrum summarizes an individual image or spatial region of interest (ROI), and used to predict large (>20,000) test sets of spectra. When the distributions of these large populations of predicted values are viewed as histograms they provide mean sample concentrations (peak centers) as well as uniformity (peak widths) and purity (peak shape) information. The same predicted values can also be viewed as concentration maps or images adding spatial information to the uniformity or purity presentations. Estimates of large population statistics enable a new metric for determining the optimal number of model components, based on a combination of global bias and pooled standard deviation values computed from multiple test images or ROIs. Two example datasets are presented: an artificial mixture design of three chemicals with distinct NIR spectra and samples of different cheeses. In some cases it was found that baseline correction by taking first derivatives gave more useful prediction results by reducing optical problems. Other data pretreatments resulted in negligible changes in prediction errors, overshadowed by the variance associated with sample preparation or presentation and other physical phenomena. Copyright © 2007 John Wiley & Sons, Ltd. [source] Continuous peripheral nerve block catheter tip adhesion in a rat modelACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 6 2006C. C. Buckenmaier III Background:, Continuous peripheral nerve block (CPNB) has been used effectively in combat casualties from Iraq and Afghanistan to provide surgical anesthesia and extended duration analgesia during evacuation and convalescence. Little information is available concerning catheter tip tissue reaction with prolonged use. Methods:, Forty-eight male Sprague-Dawley rats were assigned (12 per group) to one of four catheter tip designs provided by Arrow International: group A, 20-gauge catheter with three side-holes and a bullet-shaped tip; group B, 19-gauge StimuCathÔ catheter with coiled omni-port end with hemispherical distal tip; group C, 19-gauge catheter with single end-hole in conducting tip; group D, 19-gauge catheter with closed conducting tip with four side-holes. Following laparotomy, a randomly assigned catheter tip was sutured to the parietal peritoneal wall with the tip extending between experimental injuries created on the abdominal wall and cecum. After 7 days in situ, the catheter tips were removed from the adhesion mass using a force gauge, and the grams of force needed for removal were recorded. Results:, The mean force ± standard deviation values were 1.09 ± 1.21 g for group A, 21.20 ± 30.15 g for group B, 0.88 ± 1.47 g for group C and 1.60 ± 2.50 g for group D. The variation of each catheter group mean force compared with that of group B was significant (P < 0.05). There was no significant difference in adhesion force between groups A, C and D. Conclusions:, These results suggest that the manufactured design of a CPNB catheter tip can contribute to the adhesion of the tip in an intense inflammatory environment. This finding may have important clinical implications for CPNB catheters left in place for extended periods of time. [source] Theoretical investigation on multinuclear NMR chemical shifts of some tris(trifluoromethyl)boron complexesMAGNETIC RESONANCE IN CHEMISTRY, Issue 8 2009Jun Zhang Abstract Tris(trifluoromethyl)boron complexes have unusual properties and may find applications in many fields of chemistry, biology, and physics. To gain insight into their NMR properties, the isotropic 11B, 13C, and 19F NMR chemical shifts of a series of tris(trifluoromethyl)boron complexes were systematically studied using the gauge-included atomic orbitals (GIAO) method at the levels of B3LYP/6-31 + G(d,p)//B3LYP/6-31G* and B3LYP/6-311 + G(d,p)//B3LYP/6-311 + G(d,p). Solvent effects were taken into account by polarizable continuum models (PCM). The calculated results were compared with the experimental values. The reason that the structurally inequivalent fluorine atoms in a specific species give a same chemical shift in experimental measurements is attributed to the fast rotation of CF3 group around the BC(F3) bond because of the low energy barrier. The calculated 11B, 13C(F3), and 19F chemical shifts are in good agreement with the experimental measurements, while the deviations of calculated 13C(X, X = O, N) chemical shifts are slightly large. For the latter, the average absolute deviations of the results from B3LYP/6-311 + G(d,p)//B3LYP/6-311 + G(d,p) are smaller than those from B3LYP/6-31 + G(d,p)//B3LYP/6-31G*, and the inclusion of PCM reduces the deviation values. The calculated 19F and 11B chemical shieldings of (CF3)3BCO are greatly dependent on the optimized structures, while the influence of structural parameters on the calculated 13C chemical shieldings is minor. Copyright © 2009 John Wiley & Sons, Ltd. [source] Development of a simultaneous liquid,liquid extraction and chiral derivatization method for stereospecific GC-MS analysis of amphetamine-type stimulants in human urine using fractional factorial designBIOMEDICAL CHROMATOGRAPHY, Issue 9 2008W. R. Wan Aasim Abstract A stereospecific gas chromatography,mass spectrometry analysis method for amphetamine-type stimulants in human urine was recently developed. For maximum efficiency, liquid,liquid extraction and chiral derivatization of the analytes using (R)-(,)- , -methoxy- , -(trifluoromethyl)phenylacetyl chloride were performed simultaneously. The effects of (1) use of saturated sodium chloride in 2.0 m sodium hydroxide, (2) extraction solvent volume, (3) percentage of triethylamine, (4) derivatization reagent volume, (5) sample mixing time, (6) incubation temperature and (7) incubation time on method sensitivity and variability were assessed using a two-level, eight-run Plackett,Burman design followed by a fold-over design. The use of saturated sodium chloride solution and the derivatization reagent volume were significant factors (ANOVA, p < 0.01). The saturated sodium chloride solution decreased sensitivity whereas an increased volume of derivatization reagent increased sensitivity. Calibration curves for all analytes were linear between 5 and 500 µg/L, with correlation coefficients of >0.99. Detection limits were ,2.3 µg/L and quantitation limits ,7.7 µg/L. Reproducibility was good, with relative standard deviation values at <20%. Recovery exceeded 100% for most analytes. The experimental design enabled easy and rapid identification of significant factors using a minimal number of samples. This method has good potential for studies requiring rapid and sensitive stereospecific quantification of amphetamine-type stimulants. Copyright © 2008 John Wiley & Sons, Ltd. [source] A simple and simultaneous determination of acyclovir and ganciclovir in human plasma by high-performance liquid chromatographyBIOMEDICAL CHROMATOGRAPHY, Issue 8 2003Daisuke Teshima Abstract A simple high-performance liquid chromatographic method was developed for the simultaneous determination of the therapeutic levels of acyclovir and ganciclovir in human plasma. After precipitation of plasma proteins with 6% perchloric acid, acyclovir and ganciclovir were simultaneously determined by reversed-phase chromatography with spectophotometric detection at 254 nm. The peak heights for acyclovir and ganciclovir were linearly related to their concentrations ranging from 0.063 to 2.080 µg/mL. The recovery was 100.48,102.84% for acyclovir and 99.26,103.07% for ganciclovir. The intra- and inter-day relative standard deviation values were in the range 0.186,8.703% for acyclovir and 0.137,6.424% for ganciclovir. The detection limits for both compounds were 0.01 µg/mL determined as the signal-to-noise ratio of 3. The present method is applicable to therapeutic monitoring during antiviral medication. Copyright © 2003 John Wiley & Sons, Ltd. [source] | ||||||||||