RefQSR: Reference-Based Quantization for Image Super-Resolution Networks.

Single image super-resolution (SISR) aims to reconstruct a high-resolution image from its low-resolution observation. Recent deep learning-based SISR models show high performance at the expense of increased computational costs, limiting their use in resource-constrained environments. As a promising solution for computationally efficient network design, network quantization has been extensively studied. However, existing quantization methods developed for SISR have yet to effectively exploit image self-similarity, which is a new direction for exploration in this study. We introduce a novel method called reference-based quantization for image super-resolution (RefQSR) that applies high-bit quantization to several representative patches and uses them as references for low-bit quantization of the rest of the patches in an image. To this end, we design dedicated patch clustering and reference-based quantization modules and integrate them into existing SISR network quantization methods. The experimental results demonstrate the effectiveness of RefQSR on various SISR networks and quantization methods.

Deep Dichromatic Model Estimation Under AC Light Sources.

The dichromatic reflection model has been popularly exploited for computer vison tasks, such as color constancy and highlight removal. However, dichromatic model estimation is an severely ill-posed problem. Thus, several assumptions have been commonly made to estimate the dichromatic model, such as white-light (highlight removal) and the existence of highlight regions (color constancy). In this paper, we propose a spatio-temporal deep network to estimate the dichromatic parameters under AC light sources. The minute illumination variations can be captured with high-speed camera. The proposed network is composed of two sub-network branches. From high-speed video frames, each branch generates chromaticity and coefficient matrices, which correspond to the dichromatic image model. These two separate branches are jointly learned by spatio-temporal regularization. As far as we know, this is the first work that aims to estimate all dichromatic parameters in computer vision. To validate the model estimation accuracy, it is applied to color constancy and highlight removal. Both experimental results show that the dichromatic model can be estimated accurately via the proposed deep network.

Comparison of patients with transient and sustained increments of antiphospholipid antibodies after acute ischemic stroke.

BACKGROUND AND PURPOSE: Antiphospholipid syndrome (APS) is one of the uncommon causes of ischemic stroke, and is associated with young and female patients. However, the significance of antiphospholipid antibody (aPL) in older ischemic stroke patients is uncertain. We aimed to examine the significance of aPLs in ischemic stroke in these older patients. MATERIALS AND METHODS: A total of 739 patients with acute ischemic stroke within 7 days of initial symptoms were collected consecutively. Clinical and laboratory data were obtained from medical records. aPLs (lupus anticoagulant, anti-cardiolipin antibody, anti-ß2glycoprotein-I antibody) were measured the day after admission and the presence of at least one antibody was regarded as positive aPL. Patients with positive aPL were rechecked after at least 12 weeks for confirmation of APS. RESULT: Of the 739 patients, 103 (13.9%) had at least one aPL initially. These patients were older, had more atrial fibrillation and higher levels of inflammatory markers. Among the 103 aPL positive patients, 41 remained positive at 3 months, 23 showed negative conversion, and 39 were not available for follow-up. Patients diagnosed with APS had higher numbers of aPL and had specifically anti-ß2glycoprotein-I IgG antibody. The patients with aPLs did not differ significantly from the others in terms of stroke subtype. CONCLUSION: aPL was rather common in ischemic stroke patients regardless of age. Although the influence of transient positive aPL on ischemic stroke remains uncertain, two or more aPLs and the presence of anti-ß2glycoprotein-I IgG may predict a diagnosis of APS.

Homocysteinemia is Associated with the Presence of Microbleeds in Cognitively Impaired Patients.

BACKGROUND & OBJECTIVE: Homocysteine is possibly associated with cerebral small vessel diseases such as leukoaraiosis, silent brain infarction and cerebral microbleeds, which are in turn associated with cognitive dysfunction. We aimed to examine the relationships between cerebral microbleeds (CMBs) and plasma total homocysteine (tHcy) level, methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and cognitive function. METHODS: A total of 819 patients with memory disturbance who visited a dementia clinic consecutively were included in this study. We retrospectively collected demographic, clinical and laboratory data including tHcy level, MTHFR C677T polymorphism and Mini-Mental State Examination (MMSE). All patients underwent brain MRI including fluid attenuated inversion recovery (FLAIR) image and T2*-weighed gradient-echo (GRE) image. Logistic regression analysis was performed to test the association between risk factors and the presence of microbleeds. RESULTS: One hundred and sixty-one (19.7%) patients had CMBs, of whom 88 (54.7%) had CMBs in the lobar region. CMBs were more common in older hypertensive male patients with hyperhomocysteinemia. In multivariable analysis, plasma tHcy remained an independent predictor of the presence of CMBs after adjusting other confounders (OR: 1.035, 95% CI: 1.009-1.062, p = 0.009). Higher plasma tHcy level was also associated with number of CMBs, TT MTHFR genotype, and lower MMSE scores. CONCLUSIONS: Elevated plasma tHcy level is related to high prevalence of CMBs and cognitive dysfunction. Lowering plasma tHcy could be helpful in cognitively impaired patients who have CMBs or the MTHFR TT genotype.

Effect of Watch-Type Haptic Metronome on the Quality of Cardiopulmonary Resuscitation: A Simulation Study.

OBJECTIVES: The aim of this study was to test the applicability of haptic feedback using a smartwatch to the delivery of cardiac compression (CC) by professional healthcare providers. METHODS: A prospective, randomized, controlled, case-crossover, standardized simulation study of 20 medical professionals was conducted. The participants were randomly assigned into haptic-first and non-haptic-first groups. The primary outcome was an adequate rate of 100-120/min of CC. The secondary outcome was a comparison of CC rate and adequate duration between the good and bad performance groups. RESULTS: The mean interval between CCs and the number of haptic and non-haptic feedback-assisted CCs with an adequate duration were insignificant. In the subgroup analysis, both the good and bad performance groups showed a significant difference in the mean CC interval between the haptic and non-haptic feedback-assisted CC groups-good: haptic feedback-assisted (0.57-0.06) vs. non-haptic feedback-assisted (0.54-0.03), p < 0.001; bad: haptic feedback-assisted (0.57-0.07) vs. non-haptic feedback-assisted (0.58-0.18), p = 0.005-and the adequate chest compression number showed significant differences- good: haptic feedback-assisted (1,597/75.1%) vs. non-haptic feedback-assisted (1,951/92.2%), p < 0.001; bad: haptic feedbackassisted (1,341/63.5%) vs. non-haptic feedback-assisted (523/25.4%), p < 0.001. CONCLUSIONS: A smartwatch cardiopulmonary resuscitation feedback system could not improve rescuers' CC rate. According to our subgroup analysis, participants might be aided by the device to increase the percentage of adequate compressions after one minute.

Noise-Robust Iterative Back-Projection.

Noisy image super-resolution (SR) is a significant challenging process due to the smoothness caused by denoising. Iterative back-projection (IBP) can be helpful in further enhancing the reconstructed SR image, but there is no clean reference image available. This paper proposes a novel back-projection algorithm for noisy image SR. Its main goal is to pursuit the consistency between LR and SR images. We aim to estimate the clean reconstruction error to be back-projected, using the noisy and denoised reconstruction errors. We formulate a new cost function on the principal component analysis (PCA) transform domain to estimate the clean reconstruction error. In the data term of the cost function, noisy and denoised reconstruction errors are combined in a region-adaptive manner using texture probability. In addition, the sparsity constraint is incorporated into the regularization term, based on the Laplacian characteristics of the reconstruction error. Finally, we propose an eigenvector estimation method to minimize the effect of noise. The experimental results demonstrate that the proposed method can perform back-projection in a more noise-robust manner than the conventional IBP, and harmoniously work with any other SR methods as a post-processing.

Novel Calcium Zirconate Silicate Cement Biomineralize and Seal Root Canals.

This study evaluated the sealing ability of gutta-percha (GP) with a calcium silicate-based sealer and a novel calcium zirconate containing calcium silicate cement (ZC). The root canals of the extracted premolars were prepared, which were then randomly allocated to three experimental groups (12 root canals per group) for obturation by continuous wave of condensation with the GP and AH 26 sealer (CW); obturation using a single GP with a calcium silicate-based EndoSequence BC sealer (SC); or obturation with ZC. The roots were inserted into sterile Eppendorf tubes, which were inoculated coronally with Porphyromonas gingivalis. The amount of endotoxin leakage into the apical reservoirs were measured using the Limulus Amebocyte Lysate (LAL) assay over 21 days, with comparisons made using one-way ANOVA and Scheffe's tests (α = 0.05). After 21 days, 75% of the canals that had been obturated by SC, 50% of those obturated by CW and 42% of those obturated by ZC showed endotoxin leakage. The amount of leakage was higher in the SC canals than in the CW (p = 0.031) or ZC (p = 0.03) canals, although there was no significant difference in the amount of leakage for CW and ZC (p > 0.05). X-ray diffraction revealed the presence of tricalcium silicate (Ca3SiO5) and calcium zirconate (CaZrO3) in the synthesized ZC. Scanning electron microscopy revealed mineralized precipitates on the dentin of canals obturated by ZC. The novel calcium zirconate silicate cement appears to promote biomineralization and seal root canals at least as effectively as the conventional sealer.

Systematic Review of Appropriate Robotic Intervention for Gait Function in Subacute Stroke Patients.

The purpose of this study was to critically evaluate the effects of robot-assisted gait training (RAGT) on gait-related function in patients with acute/subacute stroke. We conducted a systematic review of randomized controlled trials published between May 2012 and April 2016. This search included 334 articles (Cochrane, 51 articles; Embase, 175 articles; PubMed, 108 articles). Based on the inclusion and exclusion criteria, 7 studies were selected for this review. We performed a quality evaluation using the PEDro scale. In this review, 3 studies used an exoskeletal robot, and 4 studies used an end-effector robot as interventions. As a result, RAGT was found to be effective in improving walking ability in subacute stroke patients. Significant improvements in gait speed, functional ambulatory category, and Rivermead mobility index were found with RAGT compared with conventional physical therapy (p < 0.05). Therefore, aggressive weight support and gait training at an early stage using a robotic device are helpful, and robotic intervention should be applied according to the patient's functional level and onset time of stroke.

Improving Color Constancy in an Ambient Light Environment Using the Phong Reflection Model.

We present a physics-based illumination estimation approach explicitly designed to handle natural images under ambient light. Existing physics-based color constancy methods are theoretically perfect but do not handle real-world images well because the majority of these methods assume a single illuminant. Therefore, specular pixels selected using existing methods produce estimated dichromatic lines that are thick or curvilinear in the presence of ambient light, thus generating significant errors. Based on the Phong reflection model, we show that a group of specular pixels on a uniformly colored object, although they are subject to intensity thresholding, produce a unique dichromatic line length depending on the geometry of each image path. Assuming that the longest dichromatic line is the most desirable when estimating the chromaticity of an illuminant, ambient-robust specular pixels are also found on the same path on which the longest dichromatic line segment is generated. Therefore, we propose a method to find the optimal image path in which the specular pixels produce the longest dichromatic line. Even though the number of collected specular pixels is reduced using the proposed method, they are proven to be more accurate when determining the illuminant chromaticity even in the existing methods. Experiments with an established benchmark data set and a self-produced image set find that the proposed method is better able to locate the illuminant chromaticity compared with the state-of-the-art color constancy methods.

Reliability and validity of a dual-probe personal computer-based muscle viewer for measuring the pennation angle of the medial gastrocnemius muscle in patients who have had a stroke.

Background A dual-probe personal computer-based muscle viewer (DPC-BMW) is advantageous in that it is relatively lightweight and easy to apply. Objective To investigate the reliability and validity of the DPC-BMW in comparison with those of a portable ultrasonography (P-US) device for measuring the pennation angle of the medial gastrocnemius (MG) muscle at rest and during contraction. Methods Twenty-four patients who had a stroke (18 men and 6 women) participated in this study. Using the DPC-BMW and P-US device, the pennation angle of the MG muscle on the affected side was randomly measured. Two examiners randomly obtained the images of all the participants in two separate test sessions, 7 days apart. Intraclass correlation coefficient (ICC), confidence interval, standard error of measurement, Bland-Altman plot, and Pearson correlation coefficient were used to estimate their reliability and validity. Results The ICC for the intrarater reliability of the MG muscle pennation angle measured using the DPC-BMW was > 0.916, indicating excellent reliability, and that for the interrater reliability ranged from 0.964 to 0.994. The P-US device also exhibited good reliability. A high correlation was found between the measurements of MG muscle pennation angle obtained using the DPC-BMW and that obtained using the P-US device (p < 0.01). Conclusion The DPC-BMW can provide clear images for accurate measurements, including measurements using dual probes. It has the advantage of rehabilitative US imaging for individuals who have had a stroke. More research studies are needed to evaluate the usefulness of the DPC-BMW in rehabilitation.

Intratubular Biomineralization in a Root Canal Filled with Calcium-Enriched Material over 8 Years.

This case report describes intratubular biomineralization in root canal, filled with calcium-enriched material after 8 years of clinical maintenance. The schematic findings of dentinal tubules were investigated with scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The root canal obturation material was closely adapted to root dentin surface, suggesting the possibility of chemical bonding between the two interfaces. SEM and EDS observation of dentinal tubules showed intratubular biomineralized crystal structures with Ca/P ratio in a range of 1.30-2.12, suggesting bioactive capacity of calcium-enriched material.

Bacterial entombment by intratubular mineralization following orthograde mineral trioxide aggregate obturation: a scanning electron microscopy study.

The time domain entombment of bacteria by intratubular mineralization following orthograde canal obturation with mineral trioxide aggregate (MTA) was studied by scanning electron microscopy (SEM). Single-rooted human premolars (n=60) were instrumented to an apical size #50/0.06 using ProFile and treated as follows: Group 1 (n=10) was filled with phosphate buffered saline (PBS); Group 2 (n=10) was incubated with Enterococcus faecalis for 3 weeks, and then filled with PBS; Group 3 (n=20) was obturated orthograde with a paste of OrthoMTA (BioMTA, Seoul, Korea) and PBS; and Group 4 (n=20) was incubated with E. faecalis for 3 weeks and then obturated with OrthoMTA-PBS paste. Following their treatments, the coronal openings were sealed with PBS-soaked cotton and intermediate restorative material (IRM), and the roots were then stored in PBS for 1, 2, 4, 8 or 16 weeks. After each incubation period, the roots were split and their dentin/MTA interfaces examined in both longitudinal and horizontal directions by SEM. There appeared to be an increase in intratubular mineralization over time in the OrthoMTA-filled roots (Groups 3 and 4). Furthermore, there was a gradual entombment of bacteria within the dentinal tubules in the E. faecalis inoculated MTA-filled roots (Group 4). Therefore, the orthograde obturation of root canals with OrthoMTA mixed with PBS may create a favorable environment for bacterial entombment by intratubular mineralization.