Evidence for a high-pressure isostructural transition in nitrogen

Understanding the high-pressure behaviors of diatomic molecules (H2, O2, N2, etc) is one of the most basic as well as important objective in high-pressure physics. Under high pressure diatomic molecule solids often exhibit rich crystal polymorphs. High-pressure isostructural transitions (HPIT) in solid hydrogen and oxygen, involving considerable technical challenges, have been experimentally documented, suggesting a possible prevailing pressure-driven molecular-symmetry breaking pathway. In spite of extensive efforts, however, HPIT in nitrogen has not been observed so far. Here we present a monoclinic-to-monoclinic isostructural phase transition (λ→λ’) in solid nitrogen at approximately 50 GPa accompanied with anomalies in lattice parameter, atomic volume and Raman vibron modes. Further ab initio calculations strongly confirmed the HPIT in nitrogen, showing the weak distortion of orientation and slight rotation in nitrogen molecules possibly drive the low-pressure phase, λ-N2, to an isostructural high-pressure phase, λ’-N2 without changing crystal symmetry. In addition, we probed in detail the phase stability and revisited the pressure-temperature (P-T) phase diagram of nitrogen, discovering a new high-pressure amorphous phase, η’-N2.

Water-oriented magnetic anisotropy transition

Water reorientation is essential in a wide range of chemical and biological processes. However, the effects of such reorientation through rotation around the metal–oxygen bond on the chemical and physical properties of the resulting complex are usually ignored. Most studies focus on the donor property of water as a recognized σ donor-type ligand rather than a participant in the π interaction. Although a theoretical approach to study water-rotation effects on the functionality of a complex has recently been conducted, it has not been experimentally demonstrated. In this study, we determine that the magnetic anisotropy of a Co(II) complex can be effectively controlled by the slight rotation of coordinating water ligands, which is achieved by a two-step structural phase transition. When the water molecule is rotated by 21.2 ± 0.2° around the Co–O bond, the directional magnetic susceptibility of the single crystal changes by approximately 30% along the a-axis due to the rotation of the magnetic anisotropy axis through the modification of the π interaction between cobalt(II) and the water ligand. The theoretical calculations further support the hypothesis that the reorientation of water molecules is a key factor contributing to the magnetic anisotropy transition of this complex.

Three-dimensional mandibular changes associated with Class II elastics and extractions treatment in adult patients

Backgroud: The apllication of Class II elastic can induce the rotation of mandible and condylar response. The purpose of this study was to assess the positional and morphological alterations of mandible after orthodontic treatment with Class II elastic by using of 3-dimensional superimposition of pretreatment (T1), posttreatment (T2) and after retention (T3) CBCT data. Methods: With sequential 3D superimpositions that combined cranial base superimpositions with regional mandibular superimpositions, the virtual reference mandibles were placed to distinguish morphological changes from positional changes. The morphological changes and positional changes of mandibles were measured by comparing multiple combinations of reference and original mandibles respectively, and the corresponding paired t test was performed using SPSS (IBM SPSS version 23). Results: During orthodontic treatment (T1-T2), the mandibular molars were extruded, and the condyles were revealed apparent adaptive remodeling and upward/backward displacements. The mandible rotated backwardly and drifted backwardly/downwardly. The condylar growth and displacements were significantly different. The condylar growth did not induce isometric displacements and the forward rotation was restricted. Two years after retention (T2-T3), continuous morphological and positional changes occurred. The condylar remodeling and forward/downward displacements induced forward mandibular rotation and neutralized the backward rotation during treatment period (T1-T2). The overall positional changes (T1-T3) were translations with slight rotation. Statistically significant differences were found between the treatment and overall variables regarding the 3D rotation, condylar displacement, Pog displacement. And with the continuous morphological and positional changes, the condyle moved back to the initial position after the retention stage.Conclusion: Conclusions: the sequential 3D superimposition method can produce the reference mandibles and distinguish the morphological changes from positional alterations. The class II elastics induced mandibular complex changes including condylar adaptive remodeling and 3D rotation and translation. The condyles morphologically adapted to resist the rotation effects of Class II elastic.

Automatic analysis of image quality by ETR-1 for the On-Board Imager

The test-plate image of an image quality test tool is processed. The processing is based on quality assurance with the well-established test device ETR-1. A program is developed to analyze the parameters such as contrast, low contrast and resolution automatically. This results in more accurate patient positioning for the On-Board Imager (OBI) system. The contrast and resolution are measured by means of Bresenham’s line algorithm. The low contrast is calculated with the help of binary masking. The modulation transfer function (MTF) is also observed for the system. The developed program imports the Digital Imaging and Communications in Medicine (DICOM) image and returns the image parameters. The program can process the ideal image or the less noisy image. The no-rotation-mode or the slight-rotation-mode of the test-plate can be analyzed.

An Improved EMD-Based Dissimilarity Metric for Unsupervised Linear Subspace Learning

We investigate a novel way of robust face image feature extraction by adopting the methods based on Unsupervised Linear Subspace Learning to extract a small number of good features. Firstly, the face image is divided into blocks with the specified size, and then we propose and extract pooled Histogram of Oriented Gradient (pHOG) over each block. Secondly, an improved Earth Mover’s Distance (EMD) metric is adopted to measure the dissimilarity between blocks of one face image and the corresponding blocks from the rest of face images. Thirdly, considering the limitations of the original Locality Preserving Projections (LPP), we proposed the Block Structure LPP (BSLPP), which effectively preserves the structural information of face images. Finally, an adjacency graph is constructed and a small number of good features of a face image are obtained by methods based on Unsupervised Linear Subspace Learning. A series of experiments have been conducted on several well-known face databases to evaluate the effectiveness of the proposed algorithm. In addition, we construct the noise, geometric distortion, slight translation, slight rotation AR, and Extended Yale B face databases, and we verify the robustness of the proposed algorithm when faced with a certain degree of these disturbances.

Distal movement of upper permanent molars using midpalatal mini-implant

OBJECTIVE: To assess whether palatal mini-implants are effective as direct anchorage for distal movement of the upper molars. METHODS: It was used an acrylic model of the upper dental arch. After making a groove in the region corresponding to dental alveolus, acrylic teeth were fixed in groove with #7 wax, with the roots being previously immersed in adhesive wax. The orthodontic appliance was placed according to the Edgewise technique and then a mini-implant (SIN, São Paulo, Brazil) was inserted at the site corresponding to the palatal raphe. A 0.019 x 0.025-in stainless steel archwire was made and attached to the upper arch with elastics. A transpalatal arch bar (0.019 x 0.025in) was mounted and two hooks were soldered to it in order to retain chain elastics (Unitek, Brazil) to be connected to the mini-implant under a force of 1.5 N on each side. The maxillary model was immersed in water 40 times and photographed after each immersion, for observation of dental movements. Analysis of variance (ANOVA) and Tukey's test were employed for analyzing the obtained data. RESULTS: Molars displaced distally 3.1 mm, in average, with distal inclination ranging from 3 to 5 mm. CONCLUSIONS: Molar movements occurred due to distal inclination, with a slight rotation and no extrusive effect.

Pysa syndrome: a case report

Pisa syndrome is known to be a condition in which there is sustained involuntary flexion of the body and head to one side and slight rotation of the trunk so the person appears to lean like the Leaning Tower of Pisa.The development of Pisa syndrome is most commonly associated with prolonged treatment with antipsychotics. Although less frequently, Pisa syndrome has been reported, in patients who are receiving other medications (such as cholinesterase inhibitors and antiemetics), in those not receiving medication (idiopathic Pisa syndrome) and also patients with neurodegenerative disorders like Alzheimer's disease and multiple system atrophy.We report a case of a 67 year- old male diagnosed with Schizophrenia for 20 years. He has been following a treatment with Clozapine 400 mg/day for 4 years. Amisulpiride was added to the established regimen of antipsychotic and increased during the last month reaching the doses of 600 mg/day. Three weeks later he was observed walking with a tilt toward the right. A first physical examination revealed sustained tonic flexion of the trunk to the right side. No deficits or mental status changes during neurological exploration were shown. We prescribed biperidene hydrochloride therapy. After 24 hour side effects disappeared.As far as we know, no many cases of amisulpride-induced Pisa syndrome in the literature have been reported. This abstract presents a case of amisulpride induced Pisa syndrome.

THE EFFECTS OF FOREARM ROTATION ON THREE WRIST MEASUREMENTS: RADIAL INCLINATION, RADIAL HEIGHT AND PALMAR TILT

The purpose of this study was to evaluate and quantify the effects of forearm rotation on radial inclination, radial height and palmar tilt. Seventeen arms, nine cadaveric and eight volunteer, were examined using a radiolucent device that allowed for the controlled rotation of each arm. Lateral and posterior-anterior X-rays were taken at 5° increments which were then measured by two physicians using standardised protocol. The results revealed that all three measurements were significantly affected by forearm rotation with forearm supination increasing the apparent measurements and forearm pronation decreasing the apparent measurements. This relationship was well characterised by linear trend modelling such that forearm pronation of 10° decreased the apparent radial inclination, radial height and palmar tilt by 2.8°, 1.6 mm and 4.4°, respectively. This study demonstrates that forearm rotation is an important factor in the accurate evaluation of wrist measurements, and that slight rotation of the wrist during radiographic imaging may significantly alter management decisions given established surgical criteria.

Mesoscale predictability under various synoptic regimes

Numerical model experiments using slightly rotated terrain are compared to gauge the sentivity of mesoscale forecasts to small perturbations that arise due to small synoptic-scale wind direction errors relative to topographic features. The surface and above surface wind speed errors, as well as the precipitation forecast errors, are examined for a landfalling cold front that occurred during the California Landfalling Jets (CALJET) experiment. The slight rotation in the terrain results in nearly identical synoptic-scale forecasts, but result in substantial forecast errors on the mesoscale in both wind and precipitation. The largest mesoscale errors occur when the front interacts with the topography, which feeds back on the frontal dynamics to produce differing frontal structures, which, in turn, result in mesoscale errors as large as 40% (60%) of the observed mesoscale variability in rainfall (winds). This sensitivity differs for the two rotations and a simple average can still have a substantial error. The magnitude of these errors is very large given the size of the perturbation, which raises concerns about the predictability of the detailed mesoscale structure for landfalling fronts.