Heavy Compression Research Articles

Evaluation of preoperative visual pathway impairment in patients with non-functioning pituitary adenoma using diffusion tensor imaging coupled with optical coherence tomography.

Optic chiasma compression and associated visual impairment induced by a non-functioning pituitary adenoma (NFPA) is commonly assessed by the optic disk and retina but is inadequate to understand the entire visual pathway impairment. We aim to evaluate the use of optical coherence tomography (OCT) coupled with diffusion tensor imaging (DTI) for the preoperative evaluation of visual pathway impairment. Fifty-three patients with NFPA (categorized into mild and heavy compression subgroups) were subjected to OCT to calculate the thickness of the circumpapillary retinal nerve fiber layer (CP-RNFL), macular ganglion cell complex (GCC), macular ganglion cell layer (GCL), and macular inner plexus layer (IPL), as well as to DTI to calculate the fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values. Compared to mild compression, heavy compression caused decreased FA value, increased ADC value of several segments of the visual pathway, thin temporal CP-RNFL, and quadrant macular GCC, IPL, and GCL. Average CP-RNFL thickness, inferior-macular inner-ring IPL and GCC thicknesses, inferior CP-RNFL thickness, and superior CP-RNFL thickness were the best indicators of the impairment of the optic nerve, optic chiasma, optic tract, and optic radiation, respectively. DTI and OCT parameters can effectively evaluate visual pathway impairment and are beneficial for the objective preoperative evaluation of visual pathway impairment in patients with NFPA.

Deepfake Video Detection Based on MesoNet with Preprocessing Module

With the development of computer hardware and deep learning, face manipulation videos represented by Deepfake have been widely spread on social media. From the perspective of symmetry, many forensics methods have been raised, while most detection performance might drop under compression attacks. To solve this robustness issue, this paper proposes a Deepfake video detection method based on MesoNet with preprocessing module. First, the preprocessing module is established to preprocess the cropped face images, which increases the discrimination among multi-color channels. Next, the preprocessed images are fed into the classic MesoNet. The detection performance of proposed method is verified on two datasets; the AUC on FaceForensics++ can reach 0.974, and it can reach 0.943 on Celeb-DF which is better than the current methods. More importantly, even in the case of heavy compression, the detection rate can still be more than 88%.

A chiral mean-field equation-of-state in UrQMD: effects on the heavy ion compression stage

It is shown that the initial compression in central heavy ion collisions at beam energies of E_{mathrm {lab}}=1-10A GeV depends dominantly on the underlying equation of state and only marginally on the model used for the dynamical description. To do so, a procedure to incorporate any equation of state in the UrQMD transport model is introduced. In particular we compare the baryon density, temperature and pressure evolution as well as produced entropy in a relativistic ideal hydrodynamics approach and the UrQMD transport model, where the same equation of state is used in both approaches. Not only is the compression similar if the same equation of state is used in either dynamical model, but it also strongly depends on the actual equation of state. These results indicate that the equation of state can be studied with observables which are sensitive to the initial compression phase and maximum compression achieved in heavy ion collisions at these beam energies.

Study on damage evolution beneath spherical indenter through experiments and mechanism-based strain gradient crystal plastic simulations

Damage evolution of AA7075-T6 rolling plate with 2 mm thickness under highly compressive stress state, which is generated by spherical indentation, is studied through experiments and simulations. On the cross section of spherical deformation region, micro voids induced by crush of MgZn2 particles are observed by scanning electron microscopy (SEM) and some special characteristics are revealed including ductile tearing of the brittle particle, huddling between neighboring voids and an in-void crack, but no clue of void closure under such heavy compression. Through Electron Back-Scattered Diffraction (EBSD), strain gradient around void was found quite high (70 mm−1) and much higher than the theoretical strain gradient induced by spherical indentation (1.8 mm−1), which will result in a significant hardening effect and preventing the further shrink and closure of micro void. More insights are provided through mechanism-based strain gradient crystal plastic simulations which couples a polycrystalline, full-scale model, and a single crystal submodel. Simulation results verify the elevated strain gradient around microvoid and find strain gradient varies dramatically along the small range of void edge, which is validated by nanoindentation test around the edge of voids. Microvoid evolution controlled by strain gradient shows strong anisotropy on different cross sections. For the void at position D focused in present paper, its area on section perpendicular to Y axis (SecY) increases at the early stage of indentation, despite the compressive stress state. Influence of the orientations of adjacent grains is also studied. Void areas on SecZ and SecY are found more sensitive to the change of orientation of adjacent grain, however, the volume variation show much less sensitivity.

Shear strength of stiffened steel shear walls with considering the gravity load effect through a three-segment distribution

Former investigations have shown that the gravity load will significantly reduce the shear strength of the steel shear walls (SSW), especially in the case of a stocky wall that has high buckling stress under heavy compression load. However, only a few have been carried out on stiffened SSW, even though it has high compression buckling stress. The present study aims to narrow the knowledge gap by conducting a theoretical analysis and a numerical evaluation. The stiffened SSW is divided into several sub-walls by vertical and horizontal stiffeners. For each sub-wall, a three-segment vertical stress distribution under the gravity load is proposed. The tension field stress of inclination tension strips of each sub-wall, with considering the effect of the gravity load through the proposed three-segment vertical stress distribution, is determined through the Von Mises yield criterion. Shear strength of the wall is calculated as the sum of the shear strength of each sub-wall, while that of the boundary frame is determined according to a wall-frame model. To evaluate the proposed approach, an experimentally verified finite element model using the software ANSYS/LS-DYNA is developed. The results show that the proposed approach is able to accurately consider the gravity load effect of the stiffened SSWs of different stiffeners configurations.

Notch Signaling Response to Heavy Compression Force Induces Orthodontic Root Resorption via RANKL and IL-6 from Cementoblasts

Notch Signaling Response to Heavy Compression Force Induces Orthodontic Root Resorption via RANKL and IL-6 from Cementoblasts

A No-Reference Video Quality Assessment Model for Underwater Networks

Underwater imagery is increasingly drawing attention from the scientific community, since pictures and videos are invaluable tools in the study of the vast unknown oceanic environment that covers 90% of the planetary biosphere. However, underwater sensor networks must cope with the harsh channel that seawater constitutes. Medium range communication is only possible using acoustic modems that have limited transmission capabilities and peak bitrates of only a few dozens of kilobits per second. These reduced bitrates force heavy compression on videos, yielding much higher levels of distortion than in other video services. Furthermore, underwater video users are ocean researchers, and therefore their quality perception is also different from the generic viewers that typically take part in subjective quality assessment experiments. Computational efficiency is also important since the underwater nodes must run on batteries and their recovery is very expensive. In this paper, we propose a pixel-based no-reference video quality assessment method that addresses the described challenges and achieves good correlations against subjective scores of users of underwater videos.

Application of Diffusion‐Driven Layer‐by‐Layer Assembly for Fabricating Compact Graphene‐Based Supercapacitors

Squash to retain performance: A diffusion-driven layer-by-layer (dd-LbL) assembly method is used to prepare films composed of porous graphene oxide scaffold. Even after heavy compression, nanosheets within this scaffold remain in a corrugated state rather than restacking. As a result, when fabricated as supercapacitor electrodes, it becomes possible to compress the device into a compact form without loss in performance. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Realization of insulating state and superconductivity in the Rashba semiconductor BiTeCl

Measurements of the resistivity, Hall coefficient, and Raman spectroscopy are performed on a Rashba semiconductor BiTeCl single crystal at high pressures up to 50 GPa. We find that applying pressure first induces a theoretically predicted insulating state, followed by a superconducting phase with an insulating normal state. Upon heavy compression, another different superconducting phase is entered into with a metallic normal state. A domelike evolution of the superconducting transition temperature with pressure is obtained with a crossover from the electron to hole carriers across the boundary of the two superconducting phases. These findings imply the possible realization of a topological state of the insulating and superconducting phases in this material.

High-pressure structural properties of tetramethylsilane**Project supported by the Cultivation Fund of the Key Scientific and Technical Innovation Project from Ministry of Education of China (Grant No. 708070), the Fundamental Research Funds for the Central Universities, South China University of Technology (Grant No. 2014ZZ0069), the National Natural Science Foundation of China (Grant No. 51502189), and the Doctoral Project of Taiyuan University

High-pressure structural properties of tetramethylsilane are investigated by synchrotron powder x-ray diffraction at pressures up to 31.1 GPa and room temperature. A phase with the space group of Pnma is found to appear at 4.2 GPa. Upon compression, the compound transforms to two following phases: the phase with space groups of P21/c at 9.9 GPa and the phase with P2/m at 18.2 GPa successively via a transitional phase. The unique structural character of P21/c supports the phase stability of tetramethylsilane without possible decomposition upon heavy compression. The appearance of the P2/m phase suggests the possible realization of metallization for this material at higher pressure.

Authentication Method Using a Discrete Wavelet Transform for a Digital Moving Image

Recently, several digital watermarking techniques have been proposed for hiding data in the frequency domain of moving image files to protect their copyrights. However, in order to detect the water marking sufficiently after heavy compression, it is necessary to insert the watermarking with strong intensity into a moving image, and this results in visible deterioration of the moving image. We previously proposed an authentication method using a discrete wavelet transform for a digital static image file. In contrast to digital watermarking, no additional information is inserted into the original static image in the previously proposed method, and the image is authenticated by features extracted by the wavelet transform and characteristic coding. In the present study, we developed an authentication method for a moving image by using the previously proposed method for astatic image and a newly proposed method for selecting several frames in the moving image. No additional information is inserted into the original moving image by the newly proposed method or into the original static image by the previously proposed method. The experimental results show that the proposed method has a high tolerance of authentication to both compressions and vicious attacks.

Conceptual design of heavy ion beam compression using a wedge

Conceptual design of heavy ion beam compression using a wedge

Prevention and treatment of emergencies in thyroid patients

Aim To evaluate the surgical treatment outcomes for patients with acute complications of thyroid disease (compression syndrome, early postoperative complications - like bilateral recurrent laryngeal nerve injure, bleeding (PB) in thyroid bed and others) performed in the single medical center. Material and methods Anaplastic Thyroid Cancer (243 patients), multiglandular retrosternal goiter (25 cases), and purulent acute thyroiditis (9 observations) made heavy compression of neck and mediastinal aerodigestive organs and were the reason for emergent thyroid surgery. Were estimated intraoperative recurrent nerve (RLN) injures consequences and postoperative bleeding, made necessary for reoperations after 25663 thyroid surgeries during 36 years of the Center practice. Results Surgical intervention for Anaplastic Thyroid Cancer in all of patients has got palliative character only. Postop. lethality rate made 21,0% after emergency interventions, and 2,5% - after routine procedure. Combinations of it with radiochemotherapy has prolonged survival rate up to 13 month in 25% of cases. Follow up results of thyroid surgery in 23777 patients has found unexpected and relevant unilateral RLN injures in 251 (1.0%) and bilateral – in 91 (0.38%) cases. Recurrent laryngeal nerves and larynges reconstruction surgery allow us to decanulate more that 75% those patients. Postoperative bleeding (PB) and thyroid bad hematomas were found in 138 больных (0.58%) patients. The most often PB happened in initial and recurrent DTG (1.07%, 0.94%), TC (0.82%) patients. In most (65.5%) of cases PB began during the first 6 hours. In case of PB we parted wound edges anywhere, intubated repeatedly trachea, inspected wound; performed hemostasis and drained wound. Main sources of PB were inferior (40.38%) or superior (17.30%) thyroid artery. Source was not found in 13.35%. PB prevention included: careful hemostasis with control lavage of the wound; fascia covering of the thyroid bed and high pressure test, ligation of inferior thyroid artery in doubtful cases. Conclusion Thyroid Surgery needs precise knowledge of skull base, neck and mediastinum anatomy, safety resection of thyroid, parathyroid, under RLN visual control, thorough hemostasis and closely postoperative watching for patients.

No-reference quality assessment for DCT-based compressed image

A blind/no-reference (NR) method is proposed in this paper for image quality assessment (IQA) of the images compressed in discrete cosine transform (DCT) domain. When an image is measured by structural similarity (SSIM), two variances, i.e. mean intensity and variance of the image, are used as features. However, the parameters of original copies are actually unavailable in NR applications; hence SSIM is not widely applicable. To extend SSIM in general cases, we apply Gaussian model to fit quantization noise in spatial domain, and directly estimate noise distribution from the compressed version. Benefit from this rearrangement, the revised SSIM does not require original image as the reference. Heavy compression always results in some zero-value DCT coefficients, which need to be compensated for more accurate parameter estimate. By studying the quantization process, a machine-learning based algorithm is proposed to estimate quantization noise taking image content into consideration. Compared with state-of-the-art algorithms, the proposed IQA is more heuristic and efficient. With some experimental results, we verify that the proposed algorithm (provided no reference image) achieves comparable efficacy to some full reference (FR) methods (provided the reference image), such as SSIM.

Clinical and radiographic evaluation of biodegradable bone plates in the treatment of mandibular body fractures.

Background:Many different systems are available for the treatment of fractures ranging from the heavy compression plates for mandibular reconstruction to low profile plates for mid-facial fixation, and are made either from stainless steel, titanium or vitallium. Recently, biodegradable, self-reinforced polylactide plates and screws have been used for the internal fixation of fractures of the mandible with good results.Aim of this study:This study evaluated clinically the biodegradable bone plates for treatment of mandibular body fracture and to evaluate bone healing during the follow-up period using digital radiography.Materials and Methods:Eight patients had been suffered from mandibular body fractures were treated using Inion CPSTM bioresorbable fixation system and the healing process were followed up using digitised panoramic radiography at first week and after 1, 3 and 6 months.Results:Clinical examination of fractured segments revealed stable fixation across the fracture sites while visual and quantitative assessment of radiograph showed healing process was comparable with results previously reported by titanium bone plates.Conclusion:Open reduction and internal fixation of mandibular fractures using bioresorbable fixation system with a brief period of inter-maxillary fixation have evolved to the point where the physical properties are sufficient to withstand the post-operative loads required for fracture repair of mandibular body fractures. The foreign body reaction is a major material-related problem which requires further studies.

Influence of Plastic Deformation on Thermal Stability of Low Carbon Bainitic Steel

Bainite is metastable due to its high dislocation density, and consequently bainitic steel structures have the problem of thermal stability. Plastic deformation of bainite can further increase dislocation density and change dislocation configuration at the same time. The influence of plastic deformation on thermal stability of low carbon bainitic steel during isothermal holding at 650 °C was investigated with hardness analysis, in-situ tracing metallographic analysis and transmission electron microscopy. Bainite in the low carbon steel evolves into polygonal ferrite via recovery and recrystallization during isothermal holding at 650 °C. There is a considerably long period (about 20 h) between end of recovery and commencement of recrystallization of undeformed bainite, in which the hardness of the sample maintains a constant value slightly lower than that before reheating. Slight plastic deformation of bainite induces rearrangement of pre-existing dislocations and forming of low-energy dislocation cells inside bainite laths, which has little influence on thermal stability of bainite, whereas heavy plastic deformation results in obvious dislocation multiplication and accelerates recrystallization of bainite. Recrystallization of heavily-deformed bainite occurs preferentially at prior austenite grains boundaries. The samples subjected to heavy torsion exhibit obviously higher thermal stability than the samples subjected to heavy compression despite their same initial hardness, which can be attributed to different influences of torsion and compression on dislocations and boundaries of bainite.

Study on Measurement of Six-DOF Force/Torque for Loading Experiment on Heavy Load Equipment

According to the requirements of fatigue test of aircraft cabin, large engine and mining machinery for heavy-duty six dimensional generalized force sensors, a new method of using piezoelectric quartz as force-sensitive element on the basis of the theory of heavy force division and equivalent capacity compression is proposed in this study. Furthermore, in order to minimize the force-coupling for the six-dimension force sensor, the optimization objective function is devised and the calculation method for decoupling is also proposed, on the basis of which, the generalized force sensor with high sensitivity, high stiffness, high linearity but light in its weight is designed. At last, the static calibration experiment is carried out the result shows that the sensor has a good ability of heavy force division and capacity for equivalent compression it can be well used in large tonnage six component force loading device and fatigue test system.

Structural feature controlling superconductivity in compressed BaFe2As2

Superconductivity can be induced with the application of pressure but it disappears eventually upon heavy compression in the iron-based parent compound BaFe2As2. Structural evolution with pressure is used to understand this behavior. By performing synchrotron X-ray powder diffraction measurements with diamond anvil cells up to 26.1 GPa, we find an anomalous behavior of the lattice parameter with a S shape along the a axis but a monotonic decrease in the c-axis lattice parameter with increasing pressure. The close relationship between the axial ratio c/a and the superconducting transition temperature Tc is established for this parent compound. The c/a ratio is suggested to be a measure of the spin fluctuation strength. The reduction of Tc with the further increase of pressure is a result of the pressure-driven weakness of the spin-fluctuation strength in this material.

Effect of Isothermal-Rolling Process on the Morphology, Size and Distribution of Type II MnS

The effect of isothermal-rolling process on the morphology, size and distribution of type II MnS was studied based on Gleeble-1500 simulator. The experimental results show that the relative plasticity of type II MnS increases with deformation temperature decreasing, but, it increases first and then decreases with deformation amount increasing; Heavy compression deformation is beneficial to improve the distribution of type II MnS; The changing trends of the size of type II MnS for varying deformation amount are basically same with deformation temperature changing, i.e. the average length of sulfides is shorter, and the average width is wider at high temperature rolling process; Under the same deformation temperature, the average size of type II MnS shows cyclical change with deformation amount increasing.

CT guided embedding of 125I by puncturing tissue through the cutis in patients with metastatic lung tumors

Objective To explore the clinical application and safety of treatment of percutaneous radioactive 125I seed implantation treatment in lung metastases under CT guidance.Methods Twenty-seven lung metastatic malignancy cases (67 nodules) were studied.Eighteen cases (46 nodules) were hepatic cancer,4 cases (9 nodules) were prostate cancer,and 5 cases (12 nodules) were breast carcinoma.Diameters of lung nodules ranged from 0.5 cm to 4.0 cm with an average diameter of 2.1 cm.125I seeds were embedded under CT guidance,using 2 to 33 particles/nodule with an activity of 18.5 to 29.6 MBq/grain for each particle.Tumor matched peripheral dose was 90-120 Gy.Postoperative validation and quality evaluation followed.Results Four months later,24 nodules showed CR,30 showed PR,5 showed NC and 8 showed PD.The total effective rate was 80.6％ (54/67).In the course of treatment,11 patients had pneumothorax,3 had heavy lung compression and 4 had hemoptysis.All conditions were improved by pleural puncture or under close follow-up observation.Conclusion 125I seed implantation is an effective and safe technique in treatment of metastatic lung tumors under CT guidance. Key words: Neoplasm metastasis ; Lung ; Brachytherapy ; Iodine radioisotopes ; Tomography,X-ray computed