Principles and applications of ultrasonic-based nondestructive methods for self-healing in cementitious materials

Recently, self-healing technologies have emerged as a promising approach to extend the service life of social infrastructure in the field of concrete construction. However, current evaluations of the self-healing technologies developed for cementitious materials are mostly limited to lab-scale experiments to inspect changes in surface crack width (by optical microscopy) and permeability. Furthermore, there is a universal lack of unified test methods to assess the effectiveness of self-healing technologies. Particularly, with respect to the self-healing of concrete applied in actual construction, nondestructive test methods are required to avoid interrupting the use of the structures under evaluation. This paper presents a review of all existing research on the principles of ultrasonic test methods and case studies pertaining to self-healing concrete. The main objective of the study is to examine the applicability and limitation of various ultrasonic test methods in assessing the self-healing performance. Finally, future directions on the development of reliable assessment methods for self-healing cementitious materials are suggested.ope

Surface-Wave Based Model for Estimation of Discontinuity Depth in Concrete

In this paper, we propose an accurate and practical model for the estimation of surface-breaking discontinuity (i.e., crack) depth in concrete through quantitative characterization of surface-wave transmission across the discontinuity. The effects of three different mixture types (mortar, normal strength concrete, and high strength concrete) and four different simulated crack depths on surface-wave transmission were examined through experiments carried out on lab-scale concrete specimens. The crack depth estimation model is based on a surface-wave spectral energy approach that is capable of taking into account a wide range of wave frequencies. The accuracy of the proposed crack depth estimation model is validated by root mean square error analysis of data from repeated spectral energy transmission ratio measurements for each specimen

Risk factors for delayed and non-union following transfibular ankle arthrodesis

Background: This study was to identify risk factors associated with delayed union and non-union in patients who underwent transfibular ankle arthrodesis.Methods: This study included 43 patients who underwent ankle arthrodesis using transfibular approach between January 2012 and September 2018 and were followed up for more than 12 months. The patients were divided into two groups according to delayed union or non-union. Group A included patients who had delayed union or non-union and Group B included patients without these complications. Variables that could contribute to non-union including etiologies, age, chronic renal failure, hypertension, diabetes, smoking, pre-operative talus bone quality, pre-operative angulation of the talus and fixation methods were evaluated.Results: The mean time to bone union was 12.7±7.25 weeks. Group A included 12 patients with 5 cases of non-union and 7 cases of delayed union and group B included 31 patients. Infection of the ankle joint (OR, 1.73; p=0.041) was risk factor for non-union and delayed union on the basis of multivariate analysis.Conclusions: We concluded that infection of the ankle joint is the most significant risk factor for delayed union and nonunion in our study. Careful attention should be paid preoperatively, intraoperatively and postoperatively to patients who have this risk factor to obtain a satisfactory surgical outcome

Schwannomatosis of the tibial nerve

Schwannoma is the most common type of benign tumor arising from the sheaths of the peripheral nerves. It occurs as a solitary tumor in most cases, but when it appears in multiple forms, it is necessary to differentiate it from plexiform schwannoma, schwannomatosis, neurofibroma and malignant peripheral nerve tumors. The authors experienced schwannomatosis in the tibial nerve without the features of neurofibromatosis type 2, so here we present a case report and literature review

Finding the convex hull of a simple polygon in linear time

Though linear algorithms for finding the convex hull of a simply-connected polygon have been reported, not all are short and correct. A compact version based on Sklansky's original idea(7) and Bykat's counter-example(8) is given. Its complexity and correctness are also shown.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26420/1/0000507.pd

MAP1981c, a Putative Nucleic Acid-Binding Protein, Produced by Mycobacterium avium subsp. paratuberculosis, Induces Maturation of Dendritic Cells and Th1-Polarization

Mycobacterium avium subsp. paratuberculosis (MAP) is the causative pathogen of chronic granulomatous enteropathy (Johne's disease) in animals, and has been focused on its association with various autoimmune diseases in humans, including Crohn's disease. The discovery of novel mycobacterial antigens and exploring their role in host immunity can contribute to the advancement of effective defense strategies including vaccines and diagnostic tools. In a preliminary study, we identified cellular extract proteins of MAP that strongly react with the blood of patients with Crohn's disease. In particular, MAP1981c, a putative nucleic acid-binding protein, showed high expression levels and strong reactivity to IgG and IgM in the sera of patients. Here, we investigated the immunological features of MAP1981c and focused on its interaction with dendritic cells (DCs), confirming its immunomodulatory ability. MAP1981c was shown to recognize Toll-like receptor (TLR) 4, and induce DC maturation and activation by increasing the expression of co-stimulatory (CD80 and CD86) and MHC class I/II molecules and the secretion of pro-inflammatory cytokines (IL-6, IL-1β, and TNF-α) in DCs. This DC activation by MAP1981c was mediated by downstream signaling of TLR4 via MyD88- and TRIF-, MAP kinase-, and NF-κB-dependent signaling pathways. In addition, MAP1981c-treated DCs activated naïve T cells and induced the differentiation of CD4+ and CD8+ T cells to express T-bet, IFN-γ, and/or IL-2, but not GATA-3 and IL-4, thus indicating that MAP1981c contributes to Th1-type immune responses both in vitro and in vivo. Taken together, these results suggest that MAP1981c is a novel immunocompetent antigen that induces DC maturation and a Th1-biased response upon DC activation, suggesting that MAP1981c can be an effective vaccine and diagnostic target

Development of Micro-Heaters with Optimized Temperature Compensation Design for Gas Sensors

One of the key components of a chemical gas sensor is a MEMS micro-heater. Micro-heaters are used in both semiconductor gas sensors and NDIR gas sensors; however they each require different heat dissipation characteristics. For the semiconductor gas sensors, a uniform temperature is required over a wide area of the heater. On the other hand, for the NDIR gas sensor, the micro-heater needs high levels of infrared radiation in order to increase sensitivity. In this study, a novel design of a poly-Si micro-heater is proposed to improve the uniformity of heat dissipation on the heating plate. Temperature uniformity of the micro-heater is achieved by compensating for the variation in power consumption around the perimeter of the heater. With the power compensated design, the uniform heating area is increased by 2.5 times and the average temperature goes up by 40 °C. Therefore, this power compensated micro-heater design is suitable for a semiconductor gas sensor. Meanwhile, the poly-Si micro-heater without compensation shows a higher level of infrared radiation under equal power consumption conditions. This indicates that the micro-heater without compensation is more suitable for a NDIR gas sensor. Furthermore, the micro-heater shows a short response time of less than 20ms, indicating a very high efficiency of pulse driving

An Active and Soft Hydrogel Actuator to Stimulate Live Cell Clusters by Self-folding

The hydrogels are widely used in various applications, and their successful uses depend on controlling the mechanical properties. In this study, we present an advanced strategy to develop hydrogel actuator designed to stimulate live cell clusters by self-folding. The hydrogel actuator consisting of two layers with different expansion ratios were fabricated to have various curvatures in self-folding. The expansion ratio of the hydrogel tuned with the molecular weight and concentration of gel-forming polymers, and temperature-sensitive molecules in a controlled manner. As a result, the hydrogel actuator could stimulate live cell clusters by compression and tension repeatedly, in response to temperature. The cell clusters were compressed in the 0.7-fold decreases of the radius of curvature with 1.0 mm in room temperature, as compared to that of 1.4 mm in 37 degrees C. Interestingly, the vascular endothelial growth factor (VEGF) and insulin-like growth factor-binding protein-2 (IGFBP-2) in MCF-7 tumor cells exposed by mechanical stimulation was expressed more than in those without stimulation. Overall, this new strategy to prepare the active and soft hydrogel actuator would be actively used in tissue engineering, drug delivery, and micro-scale actuators

Hypertensive brainstem encephalopathy involving deep supratentorial regions: does only blood pressure matter?

We report on a 42-year-old female patient who presented with high arterial blood pressure of 245/150 mmHg and hypertensive brainstem encephalopathy that involved the brainstem and extensive supratentorial deep gray and white matter. The lesions were nearly completely resolved several days after stabilization of the arterial blood pressure. Normal diffusion-weighted imaging findings and high apparent diffusion coefficient values suggested that the main pathomechanism was vasogenic edema owing to severe hypertension. On the basis of a literature review, the absolute value of blood pressure or whether the patient can control his/her blood pressure seems not to be associated with the degree of the lesions evident on magnetic resonance imaging. It remains to be determined if the acceleration rate and the duration of elevated arterial blood pressure might play a key role in the development of the hypertensive encephalopathy pattern

External Use of Propolis for Oral, Skin, and Genital Diseases: A Systematic Review and Meta-Analysis

Objective. The aim of this review is to provide the available evidence on the external use of propolis (EUP) for oral, skin, and genital diseases. Method. We searched twelve electronic databases for relevant studies up to June 2016. Randomized clinical trials (RCTs) were included and analysed. Results. Of the 286 articles identified, twelve potentially relevant studies met our inclusion criteria. A meta-analysis of two studies on recurrent oral aphthae (ROA) indicated that there were no significant differences in total effective rate (TER) for pain disappearance between EUP and placebo groups (RR = 1.96, 95% CI = 0.97–3.98, and P=0.06). In two studies on skin diseases, the combined treatment of EUP with other interventions revealed significant effects on the duration of treatment or TER. In one study on genital diseases, EUP showed significant differences in genital herpes outcome measures compared to placebo. Conclusions. Our results on the effectiveness of EUP for treating oral, skin, and genital diseases are not conclusive because of the low methodological qualities and small sample sizes. Further well-designed randomized controlled trials, with high quality and large samples for specific disorders, must be conducted to obtain firm conclusions