Search

Super resolution problems are widely discussed in medical imaging. Spatial resolution of medical images are not sufficient due to the constraints such as image acquisition time, low irradiation dose or hardware limits. To address these problems, different super resolution methods have been proposed, such as optimization or learning-based approaches. Recently, deep learning methods become a thriving technology and are developing at an exponential speed. We think it is necessary to write a review to present the current situation of deep learning in medical imaging super resolution. In this paper, we first briefly introduce deep learning methods, then present a number of important deep learning approaches to solve super resolution problems, different architectures as well as up-sampling operations will be introduced. Afterwards, we focus on the applications of deep learning methods in medical imaging super resolution problems, the challenges to overcome will be presented as well. [ABSTRACT FROM AUTHOR]

The Frank elastic constants of a polymer liquid crystal are calculated. The effects of chain flexibility and screened orientational interactions are considered. A quadratic dependence in the chain length is shown to occur under certain conditions. [ABSTRACT FROM AUTHOR]

An expression for screening of the effective monomer interactions in semirigid polymer systems is developed. Anisotropic interactions dependent on monomer orientation are taken into account in an expansion of the bare potential in spherical harmonics. Using the method of Gaussian random fields previously applied to simple flexible polymers, the equation for the screened potential is given as an expansion in the density correlation functions of the effective chain. The effect of the polymer interactions on the persistence length and end-to-end distance of worm-like chains is calculated and shown to be small. [ABSTRACT FROM AUTHOR]

Presents information on a study that discovered that a cholesteric liquid crystal with negative dielectric anisotropy and with a visible wavelength selective reflection presented high memory effects when encapsulated in a polymer film. Experimental procedaure; Results and discussion; Conclusion.

Context: Spectral Computed Tomography (SPCT) acquires energy-resolved projections that can be used to evaluate the concentrations of the different materials of an object. This can be achieved by decomposing the projection images in a material basis, in a first step, followed by a standard tomographic reconstruction step. However, material decomposition is a challenging non-linear ill-posed inverse problem, which is very sensitive to the photonic noise corrupting the data. Methods: In this paper, material decomposition is solved in a variational framework. We investigate two fidelity terms: a weighted least squares (WLS) term adapted to Gaussian noise and the Kullback–Leibler (KL) distance adapted to Poisson Noise. The decomposition problem is then solved iteratively by a regularized Gauss–Newton algorithm. Results: Simulations are performed in a numerical mouse phantom and the decompositions show that KL outperforms WLS for low numbers of photons, i.e., for high photonic noise. Conclusion: In this work, a new method for material decomposition in SPCT is presented. It is based on the KL distance to take into account the noise statistics. This new method could be of particular interest when low-dose acquisitions are performed. [ABSTRACT FROM AUTHOR]

Presents a study that investigated annealing and memory effects in polymer-dispersed chiral liquid crystals. Background on the use of chiral polymer-dispersed droplets for producing switchable color displays; Description of thermal treatment; Effect of annealing on the memory state of the polymer film.

Cone-beam computed tomography (CBCT) data are, in principle, metrically exact. However, clinicians need to consider the precision of measurements of dental morphology as well as other hard tissue structures. CBCT spatial resolution, and thus image reconstruction quality, is restricted by the acquisition voxel size. The aim of this study was to assess geometric discrepancies among 3-dimensional CBCT reconstructions relative to the micro-CT reference. Methods A total of 37 permanent teeth from 9 mandibles were scanned with CBCT 9500 and 9000 3D and micro-CT. After semiautomatic segmentation, reconstructions were obtained from CBCT acquisitions (voxel sizes 76, 200, and 300 µm) and from micro-CT (voxel size 41 µm). All reconstructions were positioned in the same plane by image registration. The topography of the geometric discrepancies was displayed by using a color map allowing the maximum differences to be located. Results The maximum differences were mainly found at the cervical margins and on the cusp tips or incisal edges. Geometric reconstruction discrepancies were significant at 300-µm resolution (P = .01, Wilcoxon test). Conclusions To study hard tissue morphology, CBCT acquisitions require voxel sizes smaller than 300 µm. This experimental study will have to be complemented by studies in vivo that consider the conditions of clinical practice. [ABSTRACT FROM AUTHOR]

Abstract: In early breast cancer (eBC), established clinicopathological factors are not sufficient for clinical decision making particularly regarding adjuvant chemotherapy since substantial over- or undertreatment may occur. Thus, novel protein- and molecular markers have been put forward as decision aids. Since these potential prognosis and/or predictive tests differ substantially regarding their methodology, analytical and clinical validation, this review attempts to summarize the essential facts for clinicians. This review focuses on those markers which are the most advanced so far in their development towards routine clinical application, i.e. two protein markers (i.e. uPA/PAI-1 and IHC4) and six molecular multigene tests (i.e. Mammaprint®, Oncotype DX®, PAM50, Endopredict®, the 97-gene genomic grade, and 76 gene Rotterdam signatures). Next to methodological aspects, we summarized the clinical evidences, in particular the main prospective clinical trials which have already been fully recruited (i.e. MINDACT, TAILORx, WSG PLAN B) or are still ongoing (i.e. RxPONDER/SWOG S1007, WSG-ADAPT). Last but not least, this review points out the key elements for clinicians to select one test among the wide panel of proposed assays, for a specific population of patients in term of level of evidence, analytical and clinical validity as well as cost effectiveness. [Copyright &y& Elsevier]

Background The causes of dental crowding are not fully understood, but it may result from an evolutionary trend towards reduced facial volume, without a proportional reduction in tooth sizes. Most previous studies conducted among modern humans have revealed a very low or non-existent correlation between tooth size and jaw size. Cross-comparison between dental age and facial skeletal age could help to provide better knowledge of the dynamic process of dental crowding. The primary objective of this research was to study the synchronism of dental maturation and skeletal facial growth in a sample of modern children living in France. The secondary objective was to assess the link between dentofacial asynchronism and dental crowding. Results The random sample comprised 28 subjects (16 girls, 12 boys). Mean chronological age was 13.5 years (±2.1; range 9.2-17.6). Mean dental age was 14.2 years (±2.8; range 7.5-17) and mean facial skeletal age was 12.8 years (±2.6, range 7-22). In the estimations of dental age and facial skeletal age, there was no evidence of systematic bias. There were 10 subjects (9 girls, 1 boy) with asynchronous dentofacial development. Finally, there were 13 subjects (8 girls, 5 boys) with dental crowding. A significant association was found between delayed facial skeletal growth / advanced dental maturation and dental crowding (P = 0.01). Conclusions Dental maturation and facial growth are not necessarily synchronous. Further understanding of the interactions between dental maturation and facial growth could have crucial implications in biological anthropology, as well as for the clinical practice of orthodontists. From an anthropological perspective, this study suggests that asynchronous dentofacial development could, at least partially, explain the frequency of dental crowding in modern populations. [ABSTRACT FROM AUTHOR]

Copyright of Revue de Stomatologie & de Chirurgie Maxillo-Faciale is the property of Masson SPA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Diabetes & Metabolism is the property of Masson Editeur and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: The goal of this study was to determine the efficacy of the intraosseous (IO) injections of anesthetic as a primary technique in children and adolescents. Study design: A cohort of 181 children and adolescents underwent a total of 225 sessions of IO injections of 4% articaine with 1:200,000 epinephrine using the Quick Sleeper 2 system. Results: Evaluations could be performed in 215 sessions (171 patients, 247 teeth), yielding success rates of 91.2% (sessions) and 91.9% (teeth). The success rate was 95% (133 of 140) for temporary teeth (endodontics 96.6%, restorations 100%, extractions 88%) and 87.9% (94 of 107) for permanent teeth (endodontics 92.3%, restorations 89.9%, extractions 75%). No difference was noted in terms of age (P > .05). No cases of biting of mucosa or postinjection pain were noted. Conclusions: The IO injection of anesthetic using a computer-controlled osseous perforation and delivery system can be considered as a good alternative or supplement to classic infiltration techniques in children and adolescents. [Copyright &y& Elsevier]

The structural reorganization of polyoxymethylene powders during sintering has been investigated through a detailed analysis of the SAXS data in order to determine the origin of the mechanical property improvement with regard to the compression-moulded counterpart. Two approaches afford a quantitative evaluation of the structural parameter evolutions. On one hand, the correlation and interface distribution functions were calculated for the samples submitted to various thermo-mechanical treatments. On the other hand, the Hosemann's paracrystalline model modified with Reinhold distributions of the crystal and amorphous phase thicknesses was used to evaluate the disorder in the lamella stacking. Both approaches suggest that a more perfect and regular crystalline structure with thicker and wider crystals develops in the sintered samples as compared with the parent powders and the material crystallized from the melt. Theses morphological modifications are discussed in relation to the very high stiffness and brittleness of the sintered materials. Two possible mechanisms of coalescence of the powder grains via the crystalline phase are proposed to account for these specific mechanical properties of the sintered materials. [ABSTRACT FROM AUTHOR]

The goal of this work is to contribute to ethical reflection in the dental profession through the example of a survey of ethical reflection and ethical issues in dentistry conducted at the dental school of Toulouse. A written survey was given to the heads of departments and to the sixth-year students and also to the dental faculty at the hospital dental clinic in order to estimate their level of understanding and concern about these topics. [ABSTRACT FROM AUTHOR]

Background: Giving the immunosuppressive drug tacrolimus (FK506) to liver transplant patients has helped to considerably reduce oral side effects such as gingival hyperplasia. Patients taking cyclosporin who suffer from gingival hyperplasia are often switched to tacrolimus. Methods: We present here a pediatric liver transplantation case study. The patient has been followed for 5.5 years. She developed oral lesions that resulted in the immunosuppressive therapy being changed from tacrolimus to cyclosporin. In clinical terms, the atypical pathology consisted of hyperpigmented patches on the gingival margin, the internal surfaces of the cheeks, and the intraoral surfaces of the lips. When located on the tips, the hyperpigmented patches were associated with pruriginous and edematous lesions. Results: Optical and electronic microscopic examinations of a gingival tissue sample revealed the presence of melanin incontinence and lichenoid lesions with degenerated keratinocytes and a mild infiltrate of lymphocytes. This points to a chronic graft-versus-host disease (cGuHD)-like syndrome linked to tacrolimus. This diagnosis was given further credence by improvement in the lesions following the switch to cyclosporin. Conclusion: To our knowledge, this is the first reported case of tacrolimus-associated chronic GuHD-like syndrome occurring in the oral mucosa. [ABSTRACT FROM AUTHOR]

Background: It has been suggested that locally produced immunoglobulin (Ig)A could be more protective than IgG and that there could be a relationship between crevicular fluid-specific: IgA levels and the onset of periodontal disease. This study was designed to investigate this hypothesis regarding specific immune responses towards 4 plaque anaerobes in gingival crevicular fluid and saliva from patients with periodontopathies arid controls. Methods: Gingival crevicular fluid (GCF) and whole saliva were collected from 35 adults with periodontitis and 24 periodontally healthy adults (controls). Antigens were extracted from Actinomyces actinomycetemcomitans, Porphyromonas gingivalis Prevotella intermedia, and Fusobacterium nucleatum and used to set up specific enzyme-linked immunosorbent assay (ELISA) tests to assess IgA and IgG levels to these microorganisms in the fluids collected. Results: The crevicular fluid of periodontitis patients contained significantly higher levels of IgG to the 4 microorganisms tested than that of controls (P <10-6 for all comparisons). IgA levels to the 4 bacteria were statistically significantly much higher in control crevicular fluid (P <10-7 for all comparisons). Controls also had statistically significantly higher levels of specific salivary IgA than patients (P <0.02 for oil comparisons). Conclusions: These data support the potentially protective role of specific IgA directed to oral microorganisms involved in the onset and development of periodontal disease. [ABSTRACT FROM AUTHOR]

We have studied the influence of polymer network liquid crystal alignment on optical and electro-optical properties. Composite alignment (parallel/homeotropic) was investigated in comparison with symmetric parallel/parallel and homeotropic/homeotropic alignments. The applied voltage leads to a reflective wavelength shift towards low wavelengths according to two modes in the case of symmetric planar alignment. Depending on polymerization conditions, a band broadening can be obtained, but a total reversibility of the optical properties is not recovered after application of a high voltage to the samples. The layer thickness appears to be a fundamental parameter in the case of a hybrid-aligned active layer and a wide band is obtained after measurements (I-V) using increasing voltages. [ABSTRACT FROM AUTHOR]