Axial Distortion Research Articles

Are Non-dysplastic Crypts with Corrupted Shapes the Initial Recordable Histological Event in the Development of Sporadic Conventional Adenomas?

Colonic crypts with normal epithelial lining displaying corrupted shapes (called non-dysplastic crypts with corrupted shapes, NDCs) were earlier recorded underneath the adenomatous glands of conventional colon adenomas in rats. To assess the frequency of NDCs in clinical sporadic conventional (tubular/villous) adenomas. NDCs found underneath the adenomatous epithelium in 255 sporadic conventional adenomas removed at endoscopy were classified into four groups: i) With fission distortions, ii) with length distortions, iii) with outline distortions, and iv) with axial polarity distortions. In 22 controls, the colonic mucosa proximal or distal to surgically removed colonic adenocarcinomas was scrutinized for NDCs. Nearly three-quarters of the sporadic conventional adenomas investigated here had three or more NDCs underneath the adenomatous tissue, those with ≥4 NDCs being more frequent (46.3%) than those having 1, 2 or 3 NDCs (p<0.05). Nineteen out of the 22 control colon segments had normal crypts and the remaining three had occasional NDCs (mean=3.7, range=2-5). NDCs were found underneath the adenomatous glands in all 255 sporadic conventional adenomas. Occasionally, NDCs were present in the mucosa of the stalk of pediculated conventional adenomas. The absence of adenomatous tissue in NDCs of the stalk should rule out the possibility that the adenomatous tissue on top had directly orchestrated the development of NDCs below. Moreover, NDCs rarely occurred in controls. Accordingly, NDCs emerge as a genuine phenomenon of crypt deformation in sporadic conventional adenomas. Considering that human colonic crypts typically divide at most once or twice during a lifetime, with an average crypt cycle length of 36 years, the accumulation of NDCs underneath sporadic conventional adenomas is remarkable. In light of these considerations, it is suggested that these putative mutated NDCs may represent the initial histological recordable event heralding the development of sporadic conventional adenomas in the human colon.

Optimization of Process Parameters for the Axial Distortion and Distortion Range During Die Quenching of a Spiral Bevel Gear

The strength of high-duty gears can be improved by carburizing and quenching processes. Quenching distortion is inevitable during the process, and it has direct effects on the precision of the gear. For spiral bevel gear with big diameter and small thickness, die quenching process is applied in the manufacturing to control the distortion in axial direction. Die quenching parameters must be optimized to minimize the distortion while considering non-uniformity of chemical compositions and loads. In this paper, material models of gear material (22CrMoH) built based on the phase transformation kinetics, static mechanical properties and phase transformation plasticity equations. Finite element analysis (FEA) models are conducted to study the whole die quenching process based on the production process. Die quenching experiments and testing of microstructures and distortions are conducted to verify the accuracy of the FEA models. The effects of loads and bottom die obliquity on the final distortion are studied to set the appropriate range and control distortion. The distortion was very sensitive to the bottom die obliquity and some part of load ranges. The distortion changes little when the load of inner die was in the range of 1.38-2.07 MPa and the load of outer die was in the range of 2.07-2.76 MPa. The distortion range is fitted the production requirements by setting the inclination angle of bottom die between 0.12° and 0.29°.

Morphological Classification of Corrupted Colonic Crypts in Ulcerative Colitis

In ulcerative colitis (UC) the colonic mucosa shows, in addition to a high number of inflammatory cells, crypts with architectural distortions, called corrupted colonic crypts (CCC). Here we classify the histologic repertoire and assess the frequency of CCC in UC. Five-hundred and sixteen histologic sections from 29 colectomy specimens with UC (24 having adenocarcinoma and five, high-grade dysplasia, HGD) were reviewed. The vast majority of the colonic mucosa portrayed countless crypts with normal shapes (CNS) lined with normal epithelium, except for 45 CNS: 28 showed inconclusive-suspected cellular changes (ISCC), and 17, high-grade dysplasia (HGD). CCC were subdivided into four groups: i) Crypts with fission distortions, ii) Crypts with length distortions, iii) Crypts with outline distortions and iv) Crypts with axial polarity distortions. The most frequent CCC group had axial polarity distortions (33.4%), and the less frequent CCC group, outline distortions (21.1%) (p<0.05). No apparent differences in frequency between groups were found in colectomies with HGD/carcinoma, or in colectomies preformed for medically-refractory UC without HGD/carcinoma. Out of the 902 CCC present in the specimens, 343 (38.0%) displayed ISCC, 186 (20.6%) HGD, and the remaining 373 (41.4%) normal epithelium. Hence, of the 203 crypts exhibiting HGD, 186 (91.6%) were CCC and the remaining 17 (8.4%) CNS (p<0.05). Based on these findings it is suggested that the microscopic search for HGD in UC colectomy-specimens should preferentially be focused on mucosal areas exhibiting CCC. This view is validated by recent findings showing that p53 overexpression (a biomarker of epithelial carcinogenesis) significantly correlated with architectural distortions of the crypts in UC.

Theoretical and experimental models for the synthesis of single-walled carbon nanotubes and their electrochemical properties

A major challenge in the field of selective synthesis of single-walled carbon nanotubes (SWCNTs) via chemical vapor deposition (CVD) method is lack of established theoretical model for direct selection of metal/support catalyst to grow the corresponding SWCNTs. This has limited the application of these materials, especially, in electronics. In this report, we introduced circumferential and axial distortions in the Extended Tight Binding (ETB) equations to generate our model equations which correlated the numerical magnitude of chiral index (n, m) of SWCNTs directly with mass fractions of metal/support catalyst matrix, respectively. Theoretical predictions of our model equations showed acceptable deviations with ETB model, and two Fe2O3/Al2O3 catalysts were prepared according to this model to grow corresponding SWCNTs (10, 7) and (8, 8) via CVD pyrolysis of C6H14/N2 feedstock. High-resolution transmission electron microscopy analysis revealed bundled SWCNTs while analysis of their Raman profiles showed consistency with the radial breathing modes, diameter and energy band gaps of SWCNTs (10, 7) and (8, 8). Electrochemical analysis of the samples suggested potentials as pseudocapacitor electrodes. If fully explored and optimized, this model may complement or augment the existing in-situ epitaxial growth model.

Representative elementary volume (REV) of cementitious materials from three-dimensional pore structure analysis

The representative elementary volume (REV) is a fundamental property of a material, but no direct measurements exist for cementitious materials. In this paper, the REV of cement pastes with supplementary cementitious materials (GGBS, PFA, SF) was determined by analysing the three-dimensional pore structure (>0.2μm) using laser scanning confocal microscopy (LSCM). The effect of axial distortion inherent to LSCM on 3D pore structure was also investigated. A range of 3D pore parameters was measured using skeletonisation, maximal ball and random walker algorithms. Results show that axial distortion has insignificant effects on most parameters except Euler connectivity, average pore and throat volumes and directional diffusion tortuosities. Most pore parameters become independent of sampling volume at ≈603μm3 except diffusion tortuosities and formation factor. The REV for porosity calculated based on a statistical approach at eight realisations and 5% relative error was found to be ≈1003μm3.

Tuning of the properties of a picolinic acid-based bispidine ligand for stable copper(II) complexation

The synthesis of the hexadentate bispidine-picolinate ligand L with two tertiary amine, two para-methoxy-substituted pyridine donors (p-OMe) and a picolinate group is reported, together with its NiII, CoII, CuII and ZnII coordination chemistry. The X-ray crystal structures of the CuII and ZnII complexes confirm that the geometries are very similar to those of the unsubstituted ligand. The increased nucleophilicity of the p-OMe substituted pyridine groups leads to a significant decrease in the metal-pyridine bond length but, due to the rigidity of the adamantane-derived bispidine backbone, the other metal-donor bonds are slightly elongated, and this leads to a larger degree of axial distortion, which augments the preference of the ligand for the Jahn-Teller-active CuII center. The structural effects are supported by the dd-electronic and EPR spectra, which indicate that, for CoII, NiII and CuII, the overall ligand field strengths of the unsubstituted ligand L′ and the p-OMe-substituted derivative L are very similar, and for CuII the in-plane ligand field is significantly stronger for the p-OMe-substituted ligand L. The MII/I redox potentials with the optimized ligand L are generally more negative for the CoII, NiII and CuII complexes, indicating that the oxidized form of the complexes takes more profit of the increase in complex stability. For CuII this is analyzed on the basis of the potentiometrically determined stability constants and their correlation with the redox potentials of the substituted and unsubstituted bispidines together with a large series of published data with other ligand systems. It emerges that L is a very selective CuII ligand with a great potential for radiopharmaceutical applications.

Structure and Catalysis of Fe(III) and Cu(II) Microperoxidase-11 Interacting with the Positively Charged Interfaces of Lipids

Numerous applications have been described for microperoxidases (MPs) such as in photoreceptors, sensing, drugs, and hydrogen evolution. The last application was obtained by replacing Fe(III), the native central metal, by cobalt ion and inspired part of the present study. Here, the Fe(III) of MP-11 was replaced by Cu(II) that is also a stable redox state in aerated medium, and the structure and activity of both MPs were modulated by the interaction with the positively charged interfaces of lipids. Comparative spectroscopic characterization of Fe(III) and Cu(II)MP-11 in the studied media demonstrated the presence of high and low spin species with axial distortion. The association of the Fe(III)MP-11 with CTAB and Cu(II)MP-11 with DODAB affected the colloidal stability of the surfactants that was recovered by heating. This result is consistent with hydrophobic interactions of MPs with DODAB vesicles and CTAB micelles. The hydrophobic interactions decreased the heme accessibility to substrates and the Fe(III) MP-11catalytic efficiency. Cu(II)MP-11 challenged by peroxides exhibited a cyclic Cu(II)/Cu(I) interconversion mechanism that is suggestive of a mimetic Cu/ZnSOD (superoxide dismutase) activity against peroxides. Hydrogen peroxide-activated Cu(II)MP-11 converted Amplex Red® to dihydroresofurin. This study opens more possibilities for technological applications of MPs.

Seven Approaches to Elimination of the Inherent Systematic Errors in Determination of Electrophoretic Mobility by Capillary Electrophoresis.

Electrophoretic mobility is a basic parameter that describes the electromigration of an ionized particle, which is used in many fields of analytical and physicochemical science. Its determination by capillary electrophoresis (CE), using a routine method, is intrinsically affected by the generation of Joule heating, entailing a drop in viscosity and possible alteration of the degree of ionization, and also by other commonly overlooked effects: axial electric field distortion and voltage ramping. The objective of this work was to provide the first theoretical overview and experimental comparison of all accessible methods that could be used to prevent these sources of inaccuracy. We have discussed seven independent approaches: (i) extrapolation of mobility to the zero power, (ii) initial buffer resistance-based correction, (iii) rational cooling adjustment, (iv) elimination of the nonthermostated capillary part, (v) inter/extrapolation to the nominal temperature, (vi) internal standard-based correction, and (vii) simple recalculation based on the temperature rise. Two methodologies (v and vi) have been proposed for the first time. Furthermore, we have shown how some approaches can be further developed, obtaining several novel and more sophisticated methods, which are also included in the comparison. Our investigation will help researchers to choose the optimal approach. We have also demonstrated for the first time how to measure the independent impact of four different effects. The outcomes reveal the compensatory character of some phenomena and explain the highly diverse and unpredictable magnitude of the total errors. The use of a correction method seems crucial for ensuring the high reliability of CE-based analyses.

Image-based correction of continuous and discontinuous non-planar axial distortion in serial section microscopy.

MotivationSerial section microscopy is an established method for detailed anatomy reconstruction of biological specimen. During the last decade, high resolution electron microscopy (EM) of serial sections has become the de-facto standard for reconstruction of neural connectivity at ever increasing scales (EM connectomics). In serial section microscopy, the axial dimension of the volume is sampled by physically removing thin sections from the embedded specimen and subsequently imaging either the block-face or the section series. This process has limited precision leading to inhomogeneous non-planar sampling of the axial dimension of the volume which, in turn, results in distorted image volumes. This includes that section series may be collected and imaged in unknown order.ResultsWe developed methods to identify and correct these distortions through image-based signal analysis without any additional physical apparatus or measurements. We demonstrate the efficacy of our methods in proof of principle experiments and application to real world problems.Availability and ImplementationWe made our work available as libraries for the ImageJ distribution Fiji and for deployment in a high performance parallel computing environment. Our sources are open and available at http://github.com/saalfeldlab/section-sort, http://github.com/saalfeldlab/z-spacing and http://github.com/saalfeldlab/z-spacing-spark.Supplementary information Supplementary data are available at Bioinformatics online

Experimental Study on the Effect of Various Types of Inlet Distortion on Surge in Axial Compressor

In axial compressor distortion at inlet leads to adverse pressure gradient at inlet of fan which leads to performance degradation and adverse effects like vibration and noise. The major distortion can lead to surge or stall in compressor. Hence, this study involves creating distortions at inlet and studying its effects on stall and performance of compressor fan. To analyze effect of distortion on compressor, an axial ducted fan is used. Study is carried out for normal flow condition, hub distortion and radial distortion conditions. Static pressure is measured in two cases. In first case, for different mass flow rate, difference in the static pressure of fan is measured, for which performance characteristic curves are plotted. In second case, normal flow inlet is distorted at operating point using above said distortion methods and difference in static pressure of fan is measured for which efficiency of fan is calculated. 60% of flow at inlet is blocked in both the cases of distortion by mechanical means using screens. Velocity across the duct at fan inlet is calculated, for which mathematical models are found. From this, average velocity from hub to tip which is necessary to find efficiency is calculated. Study shows amount of distortion not only affects stall and surge margin but also type of distortion affects surge and stall of ducted fan. Radial distortion exhibits less amount of stall margin than hub distortion for same amount of inlet flow.

Synthesis, spectral, magnetic properties, electrochemical evaluation and SOD mimetic activity of four mixed-ligand Cu(II) complexes

Four new methylsalicylato copper(II) complexes with formula [Cu(4-Mesal)2(2-Meim)2] (1), [Cu(4-Mesal)2(im)2] (2), [Cu(3-Mesal)2(bzim)2]·2H2O (3), [Cu(5-Mesal)2(im)2]n (4) (where 3-Mesal−=3-methylsalicylato, 4-Mesal−=4-methylsalicylato, 5-Mesal−=5-methylsalicylato anion, im=imidazole, 2-Meim=2-methylimidazole and bzim=benzimidazole) are reported. The solid state complexes were characterized by IR, UV–Vis, EPR, X-ray and magnetic measurements. Despite common coordination environment {CuO2N2O′2} different supramolecular structures were found for the compounds: 1 is a 1-D supramolecular chain, 2 and 3 form 2-D supramolecular networks and 4 is a 1D coordination polymer. The superoxide dismutase-like (SOD-like) activity of complexes 1–4 was studied in solution by NBT assay, compared with the activity of the parent ligand, copper acetate and native SOD enzyme and correlated to the redox stability determined by cyclic voltammetry. The exceptionally low SOD-like activity of 3, its lower redox reversibility and higher electron-withdrawing ability could be related to the lowest axial distortion of its coordination environment.

The studies of the spin Hamiltonian parameters and local structures for various 3d3 hexacyanometallates of paramagnetic salts with diluents

The spin Hamiltonian parameters (SHPs) ([Formula: see text] factors, hyperfine structure constants and zero-field splittings (ZFSs)) and local structures for various [Formula: see text] hexacyanometallates of paramagnetic salts K3Cr(CN)6 and K4V(CN)[Formula: see text]3H2O with the diluents K3Co(CN)6, K3Mn(CN)6 and K4Fe(CN)[Formula: see text]3H2O are theoretically investigated from the perturbation calculations of these parameters for a rhombically distorted octahedral [Formula: see text] cluster. The paramagnetic systems are found to undergo the local axial distortions [Formula: see text] [Formula: see text]0.19, −0.18 and 0.09 Å[Formula: see text] and the planar bond angle variations [Formula: see text] [Formula: see text] 3.5[Formula: see text], 5.3[Formula: see text] and 1.4[Formula: see text] for K3Cr(CN)6 with K3Co(CN)6, K3Cr(CN)6 with K3Mn(CN)6 and K4V(CN)[Formula: see text]3H2O with K4Fe(CN)[Formula: see text] 3H2O, respectively. The signs for ZFSs [Formula: see text] and [Formula: see text] are analyzed in the light of those for [Formula: see text] and the rhombic distortion angle [Formula: see text] [Formula: see text] related to an ideal octahedron. Microscopically, the magnitudes of [Formula: see text] and [Formula: see text] can be conveniently illustrated by the axial (ADD) and perpendicular distortion degrees (PDD), respectively, for the paramagnetic systems with the corresponding diluents. The local structural properties are analyzed from the relative ionic radius deviation [Formula: see text] of the equivalent diluent cation from the host paramagnetic cation, the axial and perpendicular ZFS variations [Formula: see text] and [Formula: see text] for ZFSs with the diluent related to the host, the relative deviation [Formula: see text]Dq of the cubic crystal-field parameter for the diluent related to the host. The above studies would be helpful to the investigations on synthesis, structures and properties of [Formula: see text] hexacyanometallates in paramagnetic salts.

Ba3(Cr0.97(1)Te0.03(1))2TeO9: in Search of Jahn-Teller Distorted Cr(II) Oxide.

A novel 6H-type hexagonal perovskite Ba3(Cr0.97(1)Te0.03(1))2TeO9 was prepared at high pressure (6 GPa) and temperature (1773 K). Both transmission electron microscopy and synchrotron powder X-ray diffraction data demonstrate that Ba3(Cr0.97(1)Te0.03(1))2TeO9 crystallizes in P63/mmc with face-shared (Cr0.97(1)Te0.03(1))O6 octahedral pairs interconnected with TeO6 octahedra via corner-sharing. Structure analysis shows a mixed Cr2+/Cr3+ valence state with ∼10% Cr2+. The existence of Cr2+ in Ba3(Cr2+0.10(1)Cr3+0.87(1)Te6+0.03)2TeO9 is further evidenced by X-ray absorption near-edge spectroscopy. Magnetic properties measurements show a paramagnetic response down to 4 K and a small glassy-state curvature at low temperature. In this work, the octahedral Cr2+O6 component is stabilized in an oxide material for the first time; the expected Jahn-Teller distortion of high-spin (d4) Cr2+ is not found, which is attributed to the small proportion of Cr2+ (∼10%) and the face-sharing arrangement of CrO6 octahedral pairs, which structurally disfavor axial distortion.

A four-coordinate cobalt(II) single-ion magnet with coercivity and a very high energy barrier.

Single-molecule magnets display magnetic bistability of molecular origin, which may one day be exploited in magnetic data storage devices. Recently it was realised that increasing the magnetic moment of polynuclear molecules does not automatically lead to a substantial increase in magnetic bistability. Attention has thus increasingly focussed on ions with large magnetic anisotropies, especially lanthanides. In spite of large effective energy barriers towards relaxation of the magnetic moment, this has so far not led to a big increase in magnetic bistability. Here we present a comprehensive study of a mononuclear, tetrahedrally coordinated cobalt(II) single-molecule magnet, which has a very high effective energy barrier and displays pronounced magnetic bistability. The combined experimental-theoretical approach enables an in-depth understanding of the origin of these favourable properties, which are shown to arise from a strong ligand field in combination with axial distortion. Our findings allow formulation of clear design principles for improved materials.

Effects of residual stresses and compressive mean stresses on the fatigue strength of longitudinal fillet-welded gussets

AbstractResults from fatigue testing of small-scale specimens are widely used to study residual stress effects on fatigue of welded structures. It was observed from a literature that welding distortion may cover residual stress effects due to high-bending stresses from clamping. Here, presented are fatigue test results and results from residual stress measurements from welded longitudinal stiffeners in different residual stress conditions. The axial welding distortion was corrected for all samples by straightening reducing effects from clamping and making residual stress effects visible. It was found that the fatigue strength depends strongly on the stabilized residual stresses, especially at high numbers of load cycles. It could be shown that residual stresses at the weld toe either were far below the yield strength or were degraded mainly at the first load cycle but still have major effects. This was investigated at two stress ratios of R = −1 and R = −3.

Insights into the Spin-State Transitions in [Fe(tpy)2]2+: Importance of the Terpyridine Rocking Motion.

Iron(II) polypyridine complexes have the potential for numerous applications on a global scale, such as sensitizers, sensors, and molecular memory. The excited-state properties of these systems, particularly the intersystem crossing (ISC) rates, are sensitive to the choice of ligands and can be significantly altered depending on the coordination environment. We employ density functional theory and Smolyak's sparse grid interpolation algorithm to construct potential energy surfaces (PESs) for the photophysically relevant states ((1)A, (3,5)MC, and (1,3)MLCT) of the [Fe(tpy)2](2+) (tpy = 2,2':6',2"-terpyridine) complex, with the goal of obtaining a deeper understanding of the ground- and excited-state electronic structure of this system. The three dimensions that define our adiabatic PESs consist of equatorial and axial metal-ligand bond length distortions and a terpyridine ligand "rocking angle", which has not previously been investigated. The intersection crossing seams and minimum energy crossing points (MECPs) between surfaces are also determined. Overall, we find that the PESs of all electronic excited states investigated are characterized by low-energy valleys along the tpy rocking-angle coordinate. This results in the presence of large low-energy areas around the MECPs on the intersection seams of different electronic states and indicates that inclusion of this third coordinate is crucial for an adequate description of the PESs and surface crossing seams of the [Fe(tpy)2](2+) complex. Finally, we suggest that tuning the energetics of the tpy ligand rocking motion could provide a way to control the ISC process in this complex.

A simple method for assessment and minimization of errors in determination of electrophoretic or electroosmotic mobilities and velocities associated with the axial electric field distortion.

It is commonly accepted that the modern CE instruments equipped with efficient cooling system enable accurate determination of electrophoretic or electroosmotic mobilities. It is also often assumed that velocity of migration in a given buffer is constant throughout the capillary length. It is simultaneously neglected that the noncooled parts of capillary produce extensive Joule heating leading to an axial electric field distortion, which contributes to a difference between the effective and nominal electric field potentials and between velocities in the cooled and noncooled parts of capillary. This simplification introduces systematic errors, which so far were however not investigated experimentally. There was also no method proposed for their elimination. We show a simple and fast method allowing for estimation and elimination of these errors that is based on combination of a long-end and short-end injections. We use it to study the effects caused by variation of temperature, electric field, capillary length, and pH.

Investigations of the spin Hamiltonian parameters and local structures for Fe3+, Cr3+ and Mn4+ in rutile TiO2 single crystal

The spin Hamiltonian parameters (g factors, hyperfine structure constants and zero-field splittings (ZFSs)) and local structures for the rhombic substitutional Fe3+, Cr3+ and Mn4+ in rutile (TiO2) single crystal are theoretically investigated from the high order perturbation calculations based on the cluster approach including both the crystal-field (CF) and charge-transfer (CT) contributions to the g factors and hyperfine structure constants. The impurity centers are found to undergo the local axial distortions ΔZ (≈0.22, 0.14 and –0.18Ǻ) and the planar bond angle variations Δφ (≈4.3, 5.9 and 0.2°) for Fe3+, Cr3+ and Mn4+, respectively. The signs for ZFSs D and E are analyzed in the light of those for ΔZ and rhombic distortion angle δφ (=φ′–π/4) related to an ideal octahedron. The magnitudes of ΔZ and Δφ are conveniently illustrated by the axial and perpendicular ZFS relative variations ΔF and ΔG for the deviations of D and E based on the local distortion parameters from those (DH and EH) based on the host structural data of Ti4+ site. The validity of the above local structures is discussed in view of size and charge mismatch of the various impurity centers. The CT contributions to g-shift are opposite in sign and about 13–56% in magnitude compared with the CF ones, indicating the increasing importance (Cr3+<Fe3+<Mn4+). The CT contributions to hyperfine structure constants are the same in sign and about 19–22% in magnitude with respect to the corresponding CF contributions.

An investigation on the defect structures and spin Hamiltonian parameters for the two orthorhombic Ti3+ centers in ZnWO4

By employing the perturbation formulae of the spin Hamiltonian parameters (SHPs) (g factors gxx, gyy, gzz, hyperfine structure constants Axx, Ayy, Azz and superhyperfine parameters Axx׳, Ayy׳, Azz׳) for a 3d1 ion in orthorhombically elongated octahedra and tetrahedra, the defect structures and the experimental EPR spectra are theoretically and systematically investigated for the two orthorhombic Ti3+ centers C1 and C2 in ZnWO4. Center C1 is ascribed to the impurity Ti3+ at host W6+ site associated with two nearest neighbor oxygen vacancies due to charge compensation. The resultant tetrahedral [TiO4]5– cluster is determined to undergo the local orthorhombic elongation distortion, characterized by the axial distortion angle Δθ (=θ–θ0≈–6.84°) of the local impurity-ligand bond angle θ related to θ0 (≈54.74°) and the perpendicular distortion angle Δε (=ε–ε0≈2.5°) related to ε0 (≈45°) of an ideal tetrahedron because of the Jahn–Teller effect. Center C2 is attributed to Ti3+ on Zn2+ site, and this octahedral [TiO6]9– cluster may experience the local axial elongation ΔZ (≈0.001Ǻ) and the planar bond angle variation Δφ (≈9.1°) due to the Jahn–Teller effect, resulting in a more regular oxygen octahedron. All the calculated SHPs (i.e., g factors for both centers, the hyperfine structure constants for center C2 and superhyperfine parameters of next nearest neighbor ligand W for center C1) show good agreement with the observed values. However, the theoretical results based on the previous assignment of center C1 as Ti3+ on W6+ site with only one nearest planar oxygen vacancy (i.e., five-fold coordinated octahedral [TiO5]7– cluster) show much worse agreement with the experimental data. The defect structures and the SHPs (especially the g anisotropies) are discussed for both centers. The present studies on the superhyperfine parameters of ligand W6+ for center C1 would be helpful to further investigations on the superhyperfine interactions of cation ligands which were rather scarcely treated before.

Treatment of camptocormia with botulinum toxin

Camptocormia is defined as an involuntary axial postural distortion of >45° flexion which occurs in the upright position, increases whilst walking and resolves when supine (Ashour and Jankovic, 2006). Unlike orthopaedic or age related kyphosis it is not a fixed structural deformity and produces kyphosis at predominantly lumbar and thoracic rather than cervical regions.Camptocormia has been reported due to a wide range of neurologic, psychiatric, muscular and orthopaedic conditions as well as rare reports of its emergence following the initiation of a number of medications (Finsterer and Strobl, 2010).Parkinson's disease (PD) includes prominent motor features of bradykinesia, rigidity and reduced postural balance responses in all those affected with this disease, but can also cause a range of other motor and non-motor features. Camptocormia is reported in a minority of patients with PD, and it is usually associated with longer disease duration and greater disease burden (Tiple et al., 2009). The aetiology of camptocormia in PD is debated, and responses to treatment have been generally poor and variable between studies. Recent studies have suggested the use of botulinum toxin may improve posture in some affected individuals.