Grayscale Levels Research Articles

Image lithography in telluride suboxide thin film through controlling “virtual” bandgap

In this work, TeO0.7 thin films were prepared by the reactive magnetron-controlling sputtering method. Complex gray-scale patterns were successfully fabricated on TeO0.7 thin films through the laser direct writing method. The structural origin of TeO0.7 thin film was investigated for gray-scale pattern formation. It is found that multiple gray-scale levels are dependent on the “virtual” bandgap energy of TeO0.7 thin films. The bandgap energy changes lead to refractive index and reflectivity difference. Thus, gray-scale tones can be formed. By accurately controlling laser energy, various “virtual” bandgaps can be generated in TeO0.7 thin films, and colorful gray-scale levels can be formed. Experimental results indicate that TeO0.7 thin film can be used as micro/nano image writing material.

Design of exposure system for the spectral sensitivity detection of the photosensitive material

To measure the spectral sensitivity of the photosensitive material, an exposure system for the spectral sensitivity detection of the photosensitive material is designed by use of commercial software of Code V and SolidWorks. The structural differences of the optical path are analyzed using line density of grating under diverse incident angle. The analysis result is that the incident angle of 25° and line density of 350 L/mm are optimum parameters of the exposure system. The experimental result in the system shows that the rectangular spectra of the size of 201.5 mm×80 mm can be achieved, the wavelengths cover the range of 360 nm~900 nm, the intensity of spectra can be adjusted in the range of 0.52 mW~10.65 mW when an 18 gray scale level of slices are inserted in the exposure system, and the resolution of spectra is 0.021 nm, which satisfies the requirement of the exposure system.

Direct imaging of a digital-micromirror device for configurable microscopic optical potentials

Programable spatial light modulators (SLMs) have significantly advanced the configurable optical trapping of particles. Typically, these devices are utilized in the Fourier plane of an optical system, but direct imaging of an amplitude pattern can potentially result in increased simplicity and computational speed. Here we demonstrate high-resolution direct imaging of a digital micromirror device (DMD) at high numerical apertures (NA), which we apply to the optical trapping of a Bose-Einstein condensate (BEC). We utilise a (1200 x 1920) pixel DMD and commercially available 0.45 NA microscope objectives, finding that atoms confined in a hybrid optical/magnetic or all-optical potential can be patterned using repulsive blue-detuned (532 nm) light with 630(10) nm full-width at half-maximum (FWHM) resolution, within 5% of the diffraction limit. The result is near arbitrary control of the density the BEC without the need for expensive custom optics. We also introduce the technique of time-averaged DMD potentials, demonstrating the ability to produce multiple grayscale levels with minimal heating of the atomic cloud, by utilising the high switching speed (20 kHz maximum) of the DMD. These techniques will enable the realization and control of diverse optical potentials for superfluid dynamics and atomtronics applications with quantum gases. The performance of this system in a direct imaging configuration has wider application for optical trapping at non-trivial NAs.

Estimation of High Speed Sintered Nylon-12 Tensile Strength Using Visible Reflectance Spectroscopy

Additive Manufacturing (AM) refers to a class of manufacturing processes which produces three dimensional objects directly from 3D model data. A range of AM processes, such as fused deposition modelling and laser sintering are deemed slow compared to injection moulding, as they depend on point-to-point consolidation. In order to progress into high speed manufacturing, a novel process called the High Speed Sintering (HSS) process is currently being developed at the University of Sheffield.HSS is a powder bed fusion process which employs an inkjet print head to print a cross sectional image of an <fig position="float" id="s37_f.1"> <label>Figure 1</label> <caption>Key components in the High Speed Sintering (HSS) process</caption> <graphic mime-subtype="tif" xlink:href="Images\s37_f01.tif" xmlns:xlink="http://www.w3.org/1999/xlink"/> </fig> object in radiation absorbing material (RAM) onto a powder build bed.[1] The build bed is subsequently exposed to infrared radiation to promote selective sintering of RAM coated powder, leaving the surrounding powder to act as a support. Consolidation is obtained by adding a new layer of powder in between printing successive images to form a 3D object. The HSS process uses Nylon-12 as its standard material, and is suitable to use with a range of polymer powder, especially thermoplastics. An overview of the HSS process with its key components is illustrated in Figure 1 below.Previous research on HSS has focused on assessing the effect of infrared lamp level,[2] the addition of flow agent[3] and the greyscale value on the mechanical properties of parts. Few studies have been performed on non-destructive characterisation of polymer parts, either by using Differential Scanning Calorimetry (DSC)[5] or NIR spectroscopy for laser sintered parts[6] and rubber parts[7]. This project aims to propose a non-destructive method to estimate the tensile properties of HSS Nylon-12 parts. Previous research based on the “greyscale level” suggested a correlation between the input ink dithering level during sintering process and the resultant parts tensile properties, however this method is not widely applicable across all inkjet print heads due to the difference in specifications. Spectroscopy method has never been used to assess parts made by the high speed sintering process and is advantageous as it quantifies an output grey level.In this contribution, an overview of the HSS processing of Nylon-12 powder will be provided. Reflectance spectroscopy will be performed on manufactured parts and the results compared with actual tensile tests. The correlation between HSS Nylon-12 parts reflectance values and their corresponding ultimate tensile strength values will be presented.

Photocuring Temperature Study for Curl Distortion Control in Projection-Based Stereolithography

Polymerization shrinkage and thermal cooling effect have been identified as two major factors that lead to the curl distortion in the stereolithography apparatus (SLA) process. In this paper, the photocuring temperature during the building process of mask image projection-based stereolithography (MIP-SL) and how it affects parts' curl distortion are investigated using a high-resolution infrared (IR) camera. Test cases of photocuring layers with different shapes, sizes, and layer thicknesses have been designed and tested. The experimental results reveal that the temperature increase of a cured layer is mainly related to the layer thickness, while the layer shapes and sizes have little effect. The photocuring temperatures of built layers using different exposure strategies including varying exposure time, grayscale levels, and mask image patterns have been studied. The curl distortions of a test case based on various exposure strategies have been measured and analyzed. It is shown that, by decreasing the photocuring temperature of built layers, the exposure strategies using grayscale levels and mask image patterns can effectively reduce the curl distortion with the expense of increased building time. In addition to curl distortion control, the photocuring temperature study also provides a basis for the curl distortion simulation in the MIP-SL process.

Image matching algorithm based on SIFT using color and exposure information

Image matching based on scale invariant feature transform (SIFT) is one of the most popular image matching algorithms, which exhibits high robustness and accuracy. Grayscale images rather than color images are generally used to get SIFT descriptors in order to reduce the complexity. The regions which have a similar grayscale level but different hues tend to produce wrong matching results in this case. Therefore, the loss of color information may result in decreasing of matching ratio. An image matching algorithm based on SIFT is proposed, which adds a color offset and an exposure offset when converting color images to grayscale images in order to enhance the matching ratio. Experimental results show that the proposed algorithm can effectively differentiate the regions with different colors but the similar grayscale level, and increase the matching ratio of image matching based on SIFT. Furthermore, it does not introduce much complexity than the traditional SIFT.

Autogenous Bone Marrow Aspirate Coated Synthetic Hydroxyapatite for Reconstruction of Maxillo-Mandibular Osseous Defects: A Prospective Study.

This prospective study was conducted to evaluate the bone regeneration capacity of synthetic hydroxyapatite mixed with autogenous bone marrow aspirate when used as a bone graft substitute in maxillo-mandibular osseous defects. This study included nine patients with histopathalogically proven benign osteolytic lesions in maxilla and mandible that were treated with enucleation or marginal resection followed by bone marrow aspirate coated synthetic biphasic hydroxyapatite (hydroxyapatite and beta tricalcium phosphate) graft placement. Incorporation of graft was assessed based on Irwin's radiologic staging. The efficacy of graft to form new bone was radiologically evaluated by observing the sequential changes of density at grafted site using gray scale level histogram which was processed in adobe photoshop 7.0 elements. Clinical assessment of recipient and donor sites was done. Based on Irwin's radiologic staging, at 6month follow up period, obvious incorporation of graft with new bone was observed. Sequential changes in bone density measured by gray scale histogram revealed initial resorption followed by replacement of BMA coated hydroxyapatite with new bone formation. None of the patients eventually had complications like infection, wound dehiscence, graft loss at recipient sites at 6months follow up period. Autogenous bone marrow aspirate in combination with synthetic hydroxyapatite is an effective option for accelerating bone regeneration in small to moderate sized jaw bone defects. This mixture provides all the three critical elements needed for bone regeneration (osteogenesis, osteoinduction and osteoconduction) with an added advantage of obviating donor site morbidity.

Use of digital panoramic radiology in presurgical implant treatment planning to accurately assess bone density

Statement of problemNo cost-effective method of ascertaining bone density from 2-dimensional radiographic images is currently available for dental implants before surgery. PurposeThe purpose of this in vivo study was to use digital panoramic radiology and dental computed tomography (CT) to evaluate the bone density of specific points in the jaw near the tooth-bearing areas. The objective was to determine whether digital panoramic radiology can be used in assessing bone density as an alternative to a more expensive and complex dental CT. Material and methodsThis study involved determining bone densities at predetermined anatomic landmarks near tooth-bearing areas of the jaws of 20 participants, using digital panoramic radiology in gray-level scale with a lead step wedge. Subsequently, the bone densities of the same points were determined in Hounsfield units (Hu) with dental CT. The data collected after interpretation of the panoramic radiograph and CT were tabulated and analyzed statistically. ResultsBone density measured using CT correlated with the first 3 steps of (A, B, and C) the digital scale of gray. Further analysis conducted using the Mann-Whitney U test showed a significant association between step A to detect D4 bone, step B to detect D3 bone, and step C to detect D2 type bone. ConclusionsThe digital scale of gray obtained from a lead step wedge can be effectively used with digital orthopanoramic radiology to assess bone density before the placement of implants, but with certain restrictions.

Ultrasound estimates of muscle quality in older adults: reliability and comparison of Photoshop and ImageJ for the grayscale analysis of muscle echogenicity.

Background. Quantitative diagnostic ultrasound imaging has been proposed as a method of estimating muscle quality using measures of echogenicity. The Rectangular Marquee Tool (RMT) and the Free Hand Tool (FHT) are two types of editing features used in Photoshop and ImageJ for determining a region of interest (ROI) within an ultrasound image. The primary objective of this study is to determine the intrarater and interrater reliability of Photoshop and ImageJ for the estimate of muscle tissue echogenicity in older adults via grayscale histogram analysis. The secondary objective is to compare the mean grayscale values obtained using both the RMT and FHT methods across both image analysis platforms.Methods. This cross-sectional observational study features 18 community-dwelling men (age = 61.5 ± 2.32 years). Longitudinal views of the rectus femoris were captured using B-mode ultrasound. The ROI for each scan was selected by 2 examiners using the RMT and FHT methods from each software program. Their reliability is assessed using intraclass correlation coefficients (ICCs) and the standard error of the measurement (SEM). Measurement agreement for these values is depicted using Bland-Altman plots. A paired t-test is used to determine mean differences in echogenicity expressed as grayscale values using the RMT and FHT methods to select the post-image acquisition ROI. The degree of association among ROI selection methods and image analysis platforms is analyzed using the coefficient of determination (R2).Results. The raters demonstrated excellent intrarater and interrater reliability using the RMT and FHT methods across both platforms (lower bound 95% CI ICC = .97–.99, p < .001). Mean differences between the echogenicity estimates obtained with the RMT and FHT methods was .87 grayscale levels (95% CI [.54–1.21], p < .0001) using data obtained with both programs. The SEM for Photoshop was .97 and 1.05 grayscale levels when using the RMT and FHT ROI selection methods, respectively. Comparatively, the SEM values were .72 and .81 grayscale levels, respectively, when using the RMT and FHT ROI selection methods in ImageJ. Uniform coefficients of determination (R2 = .96–.99, p < .001) indicate strong positive associations among the grayscale histogram analysis measurement conditions independent of the ROI selection methods and imaging platform.Conclusion. Our method for evaluating muscle echogenicity demonstrated a high degree of intrarater and interrater reliability using both the RMT and FHT methods across 2 common image analysis platforms. The minimal measurement error exhibited by the examiners demonstrates that the ROI selection methods used with Photoshop and ImageJ are suitable for the post-acquisition image analysis of tissue echogenicity in older adults.

Differences in the intensity of light-induced fluorescence emitted by resin composites

BackgroundThe aims of this study were to compare the intensities of fluorescence emitted by different resin composites as detected using quantitative light-induced fluorescence (QLF) technology, and to compare the fluorescence intensity contrast with the color contrast between a restored composite and the adjacent region of the tooth. MethodsSix brands of light-cured resin composites (shade A2) were investigated. The composites were used to prepare composite discs, and fill holes that had been prepared in extracted human teeth. White-light and fluorescence images of all specimens were obtained using a fluorescence camera based on QLF technology (QLF-D) and converted into 8-bit grayscale images. The fluorescence intensity of the discs as well as the fluorescence intensity contrast and the color contrast between the composite restoration and adjacent tooth region were calculated as grayscale levels. ResultsThe grayscale levels for the composite discs differed significantly with the brand (p<0.001): DenFil (10.84±0.35, mean±SD), Filtek Z350 (58.28±1.37), Premisa (156.94±1.58), Grandio (177.20±0.81), Charisma (207.05±0.77), and Gradia direct posterior (211.52±1.66). The difference in grayscale levels between a resin restoration and the adjacent tooth was significantly greater in fluorescence images for each brand than in white-light images, except for the Filtek Z350 (p<0.05). However, the Filtek Z350 restoration was distinguishable from the adjacent tooth in a fluorescence image. ConclusionsThe intensities of fluorescence detected from the resin composites varied. The differences between the composite and adjacent tooth were greater for the fluorescence intensity contrast than for the colors observed in the white-light images.

Intramuscular adipose tissue determined by T1-weighted MRI at 3 T primarily reflects extramyocellular lipids

PurposeThe purpose of this study was to assess relationships between intramuscular adipose tissue (IntraMAT) content determined by MRI and intramyocellular lipids (IMCL) and extramyocellular lipids (EMCL) determined by 1H magnetic resonance spectroscopy (1H MRS) or echo intensity determined by B-mode ultrasonography of human skeletal muscles. MethodsThirty young and elderly men and women were included. T1-weighted MRI was taken from the right mid-thigh to measure IntraMAT content of the vastus lateralis (VL) and biceps femoris (BF) using a histogram shape-based thresholding technique. IMCL and EMCL were measured from the VL and BF at the right mid-thigh using 1H MRS. Ultrasonographic images were taken from the VL and BF of the right mid-thigh to measure echo intensity based on gray-scale level for quantitative analysis. ResultsThere was a significant correlation between IntraMAT content by MRI and EMCL of the VL and BF (VL, r=0.506, P<0.01; BF, r=0.591, P<0.001) and between echo intensity and EMCL of the VL and BF (VL, r=0.485, P<0.05; BF, r=0.648, P<0.01). IntraMAT content was also significantly correlated with echo intensity of the VL and BF (VL, r=0.404, P<0.05; BF, r=0.493, P<0.01). ConclusionOur study suggests that IntraMAT content determined by T1-weighted MRI at 3T primarily reflects extramyocellular lipids, not intramyocellular lipids, in human skeletal muscles.

OCR Accuracy Improvement on Document Images Through a Novel Pre-Processing Approach

Digital camera and mobile document image acquisition are new trends arising in the world of Optical Character Recognition and text detection. In some cases, such process integrates many distortions and produces poorly scanned text or text-photo images and natural images, leading to an unreliable OCR digitization. In this paper, we present a novel nonparametric and unsupervised method to compensate for undesirable document image distortions aiming to optimally improve OCR accuracy. Our approach relies on a very efficient stack of document image enhancing techniques to recover deformation of the entire document image. First, we propose a local brightness and contrast adjustment method to effectively handle lighting variations and the irregular distribution of image illumination. Second, we use an optimized greyscale conversion algorithm to transform our document image to greyscale level. Third, we sharpen the useful information in the resulting greyscale image using Un-sharp Masking method. Finally, an optimal global binarization approach is used to prepare the final document image to OCR recognition. The proposed approach can significantly improve text detection rate and optical character recognition accuracy. To demonstrate the efficiency of our approach, an exhaustive experimentation on a standard dataset is presented.

Automatic color segmentation of breast infrared images using a Gaussian mixture model

Primary breast infrared images are provided in gray-level scale. For better visualization and more accurate diagnosis, they are usually converted to pseudo-color version by camera's software or external algorithms. In pseudo colored version different colors represent different temperatures. The segmentation of these images is done with the aim of division of the image to the regions with different temperatures. This is the first step in analyzing the images and will help in detecting tumor region. In this paper the color segmentation is performed using Gaussian mixture model (GMM). In this method weighted Gaussian components are fit to pixel values in RGB color space. Model parameters are estimated using the popular iterative EM algorithm. After segmentation, clusters are ordered with respect to their average temperature increasing. In order to determine the optimum number of clusters, two cluster validity indices named Calinski–Harabasz and Davies–Bouldin are used. Results showed that Davies–Bouldin index has bias toward small number of clusters. Sometimes this may lead to improper classifying of pixels, so Calinski–Harabasz index is preferred. According to the results and subjective evaluation of the specialist radiologist, the proposed method has good performance in separating regions with different temperature and can be used in screening applications.

Fractal and multifractal analyses of sphalerite banding at the Zhaishang gold deposit, western Qinling, China

Sphalerite from Carlin–type gold deposits in Zhaishang, western Qinling, China, exhibits colour banding ranging from light to dark brown. Scanning electron microscopy (SEM) and electron-probe microanalysis show that such sphalerite banding is caused by variable Fe incorporation. A linear relationship exists between grey-scale level in photomicrographs and Fe content, thus allowing the extraction of Fe compositional length scales from high spatial resolution banding. Hurst exponents and Lyaponov exponents were measured using this technique. In the outer banding region, the measured Hurst exponents range from 0.20 to 0.41 with an average of 0.32, indicating fractal scaling and anti-persistent behaviour. The values of the Lyaponov exponent range from 0.0254 to 0.0757, with an average of 0.0468, revealing weakly chaotic behaviour in the oscillatory banding pattern. Analysis of the multifractal spectrum from the inner to outer bandings indicates that, compared with the inner and outer areas in the bandings of sphalerite crystals, the middle area exhibits a greater degree of fractal behaviour. The fractal dimensions can be taken as a quantitative indicator of temperature. Furthermore, zoning patterns may reflect chaotic behaviour in a nonlinear non-equilibrium system.

Fractal Analysis of Surface Topography by the Directional Blanket Covering Method

A new method, called directional blanket covering (DBC) method, was developed in this study to quantify the roughness of surfaces in a multi-scale manner. Unlike the ASME and ISO standards on surface texture that provide a single fractal dimension (FD, roughness measure) for the entire surface, the new method calculates FDs at individual scales and directions. Also, it is invariant to affine transformations of grey-scale levels of surface image. The method calculates FDs using slopes of lines fitted to data point subsets of log–log plots of relative surface areas (differences between surface volumes) against scales of calculation. The scales are ranking from an instrument spatial resolution to 1/10 of the image shortest size. Each FD calculated has its individual scale corresponding to the centre of the subset. A flat surface criterion based on the relative areas was proposed. Using the criterion, a flat surface was identified in computer images of circle, sine wave and fractal surface. The DBC method was applied to computer-generated fractal surfaces with increasing roughness and microscope images of isotropic (sandblasted) and anisotropic (ground) surfaces of steel plates. Results showed that the method is accurate in the measurement of surface roughness and the detection of minute changes in roughness of the steel surfaces over a wide range of scales.

Autonomous rock classification using Bayesian image analysis for Rover-based planetary exploration

A robust classification system is proposed to support autonomous geological mapping of rocky outcrops using grayscale digital images acquired by a planetary exploration rover. The classifier uses 13 Haralick textural parameters to describe the surface of rock samples, automatically catalogues this information into a 5-bin data structure, computes Bayesian probabilities, and outputs an identification.The system has been demonstrated using a library of 30 digital images of igneous, sedimentary and metamorphic rocks. The images are 3.5×3.5cm2 in size and composed of 256×256 pixels with 256 grayscale levels. They are first converted to gray level co-occurrence matrices which quantify the number of times adjacent pixels of similar intensity are present. The Haralick parameters are computed from these matrices. When all 13 parameters are used, classification accuracy, defined using an empirical scoring system, is 65% due to a large number of false positives. When the number of parameters and the choice of parameter is optimized, classification accuracy increases to 80%. The best results were achieved with 3 parameters that can be interpreted visually (angular second moment, contrast, correlation) together with two statistical parameters (sum of squares variance and difference variance) and a parameter derived from information theory (information measure of correlation II).The system has been kept simple not to draw excessive computational power from the rover. It could, however, be easily extended to handle additional parameters such as images acquired at different wavelengths.

Phase discrimination and a high accuracy algorithm for PIV image processing of particle–fluid two-phase flow inside high-speed rotating centrifugal slurry pump

PIV technology is an efficient and powerful measurement method to investigate the characteristics of fluid flow field. But for PIV particle image post-processing, some problems still exit in two-phase particles discrimination and velocity field algorithm, especially for high-speed rotating centrifugal slurry pump. In this study, through summarization and comparison of the various phase discrimination methods, we proposed a two-phase identification method based on statistics of gray-scale level and particle size. The assessment of performance through experimental PIV images shows that a satisfying effect for particle identification. For high speed rotation of the impeller, a combination of adaptive cross-correlation window deformation algorithm and multistage grid subdivision is presented. The algorithm is applied to experimental PIV images of solid–liquid two-phase flow in a centrifugal slurry pump, the results show that the algorithm in the present study has less pseudo vector number and more matching particle pairs than those of fixed window and window translation methods, having the ability to remove pseudo vector efficiently. It confirmed that the algorithm proposed in the present study has good performance and reliability for PIV image processing of particle–fluid two-phase flow inside high-speed rotating centrifugal slurry pump.

Assessment of carotid plaque neovascularization using quantitative analysis of contrast-enhanced ultrasound imaging is useful for risk stratification in patients with coronary artery disease

BackgroundContrast-enhanced ultrasound (CEUS) of the carotid artery is a potential technique for imaging plaque neovascularization, a feature of unstable atherosclerotic plaques. This study examined whether assessment of intra-plaque neovascularization of the carotid artery using CEUS provides prognostic information in patients with coronary artery disease (CAD). MethodsA total of 206 patients with stable CAD underwent a CEUS examination of the carotid artery and were followed up prospectively for <38months or until a cardiac event (cardiac death, non-fatal myocardial infarction (MI), unstable angina pectoris (uAP) requiring unplanned coronary revascularization, or heart failure requiring hospitalization). The degree of contrast signals measured within the carotid plaque was quantified by calculating the mean gray scale level within the region of interest of the carotid plaque, expressed as plaque enhanced intensity. ResultsDuring the follow-up period, 31 events occurred (2 cardiac deaths, 7 non-fatal MIs, 16 uAP, and 6 heart failure). Multivariate Cox proportional hazard analysis showed that plaque enhanced intensity was a significant predictor of cardiac events independent of traditional risk factors (HR, 1.13; 95% CI, 1.05–1.21; p<0.001). The addition of the plaque enhanced intensity to traditional risk factors resulted in net reclassification improvement (NRI) and integrated discrimination improvement (IDI) (NRI 0.62, p=0.001; and IDI 0.106, p=0.002). ConclusionsThe assessment of carotid plaque neovascularization using quantitative analysis of CEUS may be useful for risk stratification in patients with CAD.

Potential Risks And Distribution Pattern Of Intramuscular Fat In Obese Children

PURPOSE: The purpose of this study was to assess relationship between IMF and physiological and biochemical variables. METHODS: Thirty-seven obese boys and girls participated in this study (age, 10.4 ± 2.1 years; height, 146.2 ± 13.4 cm; weight, 56.1 ± 16.5 kg; percentage of overweight, 41.1 ± 16.8%). This study was conducted a part of treatment of the subjects and was approved by the institutional review board of local committees. Computed tomography (CT) images were taken at the mid-thigh and umbilicus levels. Using the CT images, IMF index of the quadriceps femoris (QF), hamstrings (HM) and adductor (AD) muscle groups based on mean grey scale level of the interested muscle groups and visceral fat cross-sectional area (CSA) were calculated. For the mid-thigh CT image, skeletal muscle CSA and subcutaneous fat was also calculated. Plasma triglyceride, FFA, HDL-cholesterol, total-cholesterol, AST, ALT, glucose and HbA1c were measured from fasting blood drop. RESULTS: IMF index of QF, HM and AD was significantly different in all comparisons: HM was the lowest (1066 ± 6), meaning largest IMF depot, and QF was the highest (1080 ± 3), meaning smallest IMF depot. Stepwise regression analysis revealed that QF CSA, visceral fat CSA, and triglyceride were extracted to predict IMF index in QF (R=0.707, P < 0.01). For IMF index in HM, visceral fat CSA, age, triglyceride, percentage of overweight, and sex were extracted (R=0.806, P < 0.01). Interestingly, percentage of overweight was the only extracted variable to predict IMF index in AD (R=0.529, P < 0.01). CONCLUSIONS: These results suggest that muscle-specific IMF deposition pattern was observed in obese children and that intramuscular fat in each muscle group may have physiological and biochemical specific roles.

Absorption peaks depending on topology of the keyhole front and wavelength

By high speed imaging, wavy patterns were observed at the keyhole front in Yb:fibre laser welding. Despite a regular appearance of downstreaming wave flow in the movies, deeper image analysis shows that the pattern structure is complex. The observed grayscale levels of the flow pattern are likely to correspond to a combination of temperature, topology, and emissivity of the keyhole front, in turn originating from variations of the beam absorption, temperature, boiling, ablation pressure, and melt acceleration across the keyhole surface. Bright domains can fluctuate on a time scale of 10–100 μs. For interpretation of the fundamental mechanisms, the evidence from high speed imaging analysis is accompanied by mathematical modeling of the absorption modulation, combining local absorptivity, and beam projection. The calculated results show that for a wide range of keyhole topology parameters, lasers with a wavelength of about 1 μm induce high absorption peaks at the wave shoulders while CO2-lasers have a more homogenizing behavior. Different regimes can be distinguished.