Bond Behavior of Steel Rebar Embedded in Cementitious Composites Containing Polyvinyl Alcohol (PVA) Fibers and Carbon Nanotubes (CNTs).

In this study, pull-out tests were conducted to investigate the bond behavior of a rebar embedded in cementitious composites with polyvinyl alcohol (PVA) fibers and carbon nanotubes (CNTs). In the cementitious composites, the binder consisted of ordinary Portland cement, blast furnace slag, and fly ash, with a weight ratio of 39.5, 21.

Automatic Recognition of Road Damage Based on Lightweight Attentional Convolutional Neural Network.

An efficient road damage detection system can reduce the risk of road defects to motorists and road maintenance costs to traffic management authorities, for which a lightweight end-to-end road damage detection network is proposed in this paper, aiming at fast and automatic accurate identification and classification of multiple types of road damage. The proposed technique consists of a backbone network based on a combination of lightweight feature detection modules constituted with a multi-scale feature fusion network, which is more beneficial for target identification and classification at different distances and angles than other studies. An embedded lightweight attention module was also developed that can enhance feature information by assigning weights to multi-scale convolutional kernels to improve detection accuracy with fewer parameters.

Probabilistic Analysis for Strain-Hardening Behavior of High-Performance Fiber-Reinforced Concrete.

The practical application of fiber-reinforced concrete (FRC) in structural components has gained growing interest due to structural advantages such as improved tensile strength, distributed load transfer, crack width control, as well as superior durability. To this end, reliable structural assessment techniques and analytical models have been developed, placing emphasis on tension-softening behavior owing to the bond and pull-out mechanisms of fibers at a local crack. However, these models could not be directly applicable to evaluate the multiple cracking mechanisms of high-performance fiber-reinforced concrete (HPFRC), which exhibits strain-hardening behavior.

Electrical control of terahertz frequency conversion from time-varying surfaces.

We investigate the electrical control of frequency conversion from a time-varying interdigitated photo-conductive antenna (IPCA) and time-varying metasurface in the terahertz (THz) frequency range. Ultrafast near-infrared (NIR) optical pulses rapidly modify the conductivities of the IPCA and metasurface; however, external voltages can retard this conductivity transition. Thus, external voltages can be used to control the frequency conversion process based on the interaction between the THz waves and the time-varying surfaces.

Spectrum of MNX1 Pathogenic Variants and Associated Clinical Features in Korean Patients with Currarino Syndrome.

Background: The major genetic cause of Currarino syndrome (CS), a congenital malformation syndrome typically characterized by sacral agenesis, anorectal malformation, and presence of a pre-sacral mass, is known to be pathogenic variants in motor neuron and pancreas homeobox 1 (MNX1), which exist in almost all familial cases and 30% of sporadic cases. Less commonly, a large deletion or a complex rearrangement involving the 7q36 region is associated with CS. We investigated the spectrum of MNX1 pathogenic variants and associated clinical features in the Korean patients with CS.

Analysis of clinical features of lipoblastoma in children.

Objective: A lipoblastoma is pathologically benign but often recurs. Due to its rarity, studies are scarce. The purpose of this study was to investigate the clinical characteristics of lipoblastoma occurring in children and to detect any correlations with the expression of Ki-67.

Construction Condition and Damage Monitoring of Post-Tensioned PSC Girders Using Embedded Sensors.

The potential for monitoring the construction of post-tensioned concrete beams and detecting damage to the beams under loading conditions was investigated through an experimental program. First, embedded sensors were investigated that could measure pre-stress from the fabrication process to a failure condition. Four types of sensors were installed on a steel frame, and the applicability and the accuracy of these sensors were tested while pre-stress was applied to a tendon in the steel frame.

Autophagy plays a role in skeletal muscle mitochondrial biogenesis in an endurance exercise-trained condition.

Mitochondrial homeostasis is tightly regulated by two major processes: mitochondrial biogenesis and mitochondrial degradation by autophagy (mitophagy). Research in mitochondrial biogenesis in skeletal muscle in response to endurance exercise training has been well established, while the mechanisms regulating mitophagy and the interplay between mitochondrial biogenesis and degradation following endurance exercise training are not yet well defined. The purpose of this study was to examine the effects of a short-term inhibition of autophagy in response to acute endurance exercise on skeletal muscle mitochondrial biogenesis and dynamics in an exercise-trained condition.

Long-term functional outcomes of PPPD in children--Nutritional status, pancreatic function, GI function and QOL.

Purpose: The purpose of this study was to analyze the long-term outcomes, such as nutritional status, pancreatic function, gastrointestinal (GI) function, and quality of life (QOL), in children who underwent pylorus-preserving pancreaticoduodenectomy (PPPD).

Methods: Between 1992 and 2013, there were 15 children who underwent PPPD at Seoul National University Children's Hospital, and 10 of them participated in this study. A retrospective review of the patients' medical records and follow-up was done.

Flexural Behavior of HPFRCC Members with Inhomogeneous Material Properties.

In this paper, the flexural behavior of High-performance Fiber-Reinforced Cementitious Composite (HPFRCC) has been investigated, especially focusing on the localization of cracks, which significantly governs the flexural behavior of HPFRCC members. From four points bending tests with HPFRCC members, it was observed that almost evenly distributed cracks formed gradually, followed by a localized crack that determined the failure of the members. In order to investigate the effect of a localized crack on the flexural behavior of HPFRCC members, an analytical procedure has been developed with the consideration of intrinsic inhomogeneous material properties of HPFRCC such as cracking and ultimate tensile strengths.

Compressive Behavior of Fiber-Reinforced Concrete with End-Hooked Steel Fibers.

In this paper, the compressive behavior of fiber-reinforced concrete with end-hooked steel fibers has been investigated through a uniaxial compression test in which the variables were concrete compressive strength, fiber volumetric ratio, and fiber aspect ratio (length to diameter). In order to minimize the effect of specimen size on fiber distribution, 48 cylinder specimens 150 mm in diameter and 300 mm in height were prepared and then subjected to uniaxial compression. From the test results, it was shown that steel fiber-reinforced concrete (SFRC) specimens exhibited ductile behavior after reaching their compressive strength.

Neonatal gastric perforation: A single center experience.

Aim: To determine the etiology and prognostic factors for neonatal gastric perforation (NGP), a rare but life-threatening disease.

Methods: Between 1980 and 2011, nine patients underwent surgical intervention for NGP at Seoul National University Children's Hospital. The characteristics and prognosis of the patients were retrospectively analyzed.

Development and validation of web-based nomograms to predict postoperative invasive component in ductal carcinoma in situ at needle breast biopsy.

Objectives: Although sonography-guided core needle biopsy is a highly targeted method, there is a possibility of an invasive component after surgical excision of ductal carcinoma in situ (DCIS) of the breast. This study was performed to develop and validate nomograms to predict the postoperative invasive component in DCIS at core needle biopsy.

Methods: Two nomograms were developed using the data of previous meta-analysis and multivariate analysis.

Comparison of outcomes according to the operation for type A esophageal atresia.

Purpose: The purpose was to evaluate outcomes according to different operative strategies of type A esophageal atresia (EA).

Methods: All patients who underwent surgery for type A EA between 1980 and 2011 were included. Patients were divided into 2 groups: E-E group included patients who received esophageal end-to-end anastomosis, whereas E-G group included patients who received esophago-gastric tube anastomosis.

Long term outcomes of pediatric liver transplantation according to age.

Liver transplantation (LT) has been the key therapy for end stage liver diseases. However, LT in infancy is still understudied. From 1992 to 2010, 152 children had undergone LT in Seoul National University Hospital.

Effects of compression/stretching of the spermatic cord and blunt dissection on testicular growth and fertility.

Purpose: This study was performed to investigate whether compression/stretching of the spermatic cord or blunt dissection influences testicular development and fertility. In addition, the authors evaluated whether the extents of testicular damage differ between these 2 surgical manipulations.

Methods: Forty-four prepubertal male Sprague-Dawley (SD) rats (Harlan Sprague-Dawley Inc, Indianapolis, Ind) were divided into 3 groups: (1) the control group (CG) animals underwent a sham operation in the right groin, (2) the experimental group 1 (EG1) underwent compression/stretching of the right spermatic cord, and (3) the experimental group 2 (EG2) underwent dissection around the right spermatic cord structures.

Is the outcome of the left colon antegrade continence enema better than that of the right colon antegrade continence enema?

Background/purpose: The purpose of this report was to review the results of the antegrade continence enema (ACE) procedure and to compare the outcomes of right and left colon ACEs in children.

Methods: Thirty patients who underwent an ACE between 1998 and 2005 were analyzed. Data were obtained based on the following parameters: postoperative soiling, catheter insertion time, colonic washout time, quality of life, and abdominal pain during and after the ACE.

Vasoactive intestinal polypeptide-producing ganglioneuromatosis involving the entire colon and rectum.

Vasoactive intestinal polypeptide (VIP) is known to cause the watery diarrhea, hypokalemia, and achlorhydria syndrome. A 14-year-old girl was admitted with a 4-year history of persistent uncontrollable diarrhea and hypokalemia. Computed tomographic evaluation of the neck, chest, and abdomen were normal.

Is excision of a choledochal cyst in the neonatal period necessary?

Purpose: Although the incidence of choledochal cyst (CC) diagnosed in the prenatal or neonatal period is increasing, excision of CC in early infancy is not universally recommended. To validate the rationale of excision of CC in the neonatal period, operative complications and the histologic grade of liver fibrosis at the time of excision of CC were compared in three age groups.

Methods: 198 patients who underwent excision of CC, were divided into three age groups, i.

Situs anomalies and gastrointestinal abnormalities.

Background/purpose: The aim of the study was to review the gastrointestinal abnormalities occurring in association with situs anomalies.

Methods: Patients with situs anomalies were identified from the medical records of pediatric patients of Seoul National University Children's Hospital from January 1980 to July 2004. Retrospective study was undertaken.

Surgical treatment and prognosis of chronic intestinal pseudo-obstruction in children.

Background/purpose: Chronic intestinal pseudo-obstruction (CIPO) is characterized by symptoms of intestinal obstruction in the absence mechanical blockage. The main objectives in the treatment of CIPO include maintenance of adequate nutrition and restoration of intestinal propulsion. Our aim was to document the results of surgical treatment and the long-term results of CIPO in children.

Experience with surgical excision in childhood pheochromocytoma.

Pheochromocytoma is one of the potentially fatal causes of childhood hypertension. The study aims to analyze the results of our experiences in pheochromocytomas and the long-term results of its surgical treatment in children. The records of 15 children (11 boys, 4 girls) treated for pheochromocytoma in our unit during the period of 1984 and 2002 were reviewed retrospectively.

Diminished expression of aquaporin water channels in ureteral-obstructed kidney in rats.

Objective: We investigated whether regulation of aquaporin (AQP) water channels is altered in the ureteral-obstructed kidney.

Material And Methods: Male Sprague-Dawley rats were unilaterally obstructed of their left proximal ureters for 48 h. The protein expression of AQP1-3 channels was determined in the kidney by Western blot analysis.

Undifferentiated (embryonal) sarcoma of the liver: combination treatment by surgery and chemotherapy.

Background/purpose: Undifferentiated (embryonal) sarcoma of the liver (USL) is a rare malignancy found in older children, and the most appropriate treatment strategy has been controversial. The authors report the tumor's clinical characteristics and the results of management in 6 children and recommend the best treatment plans based on these findings.

Methods: Six USL pathologically verified at Seoul National University Children's Hospital between 1990 and 2000 were reviewed retrospectively.