Influence of geometric structure, convection, and eddy on sound propagation in acoustic metamaterial with turbulent flow

The problem of reducing noise in the transportation is an important research field to prevent accidents and to provide a civilized environment for people. A material that has recently attracted attention in research to reduce noise is acoustic metamaterial, and most of the research projects so far have been limited to the case of static media without flow. We have studied the sound transmission properties of acoustic metamaterial with turbulent flow to develop acoustic metamaterial that be used in transportation. In this paper, the effect of geometrical structure, the convective effect, and the eddy effect on sound propagation in acoustic metamaterial with turbulent flow are investigated, and the relationships between them are analyzed. The convective effect and the eddy effect both reduce the resonant strength of sound transmission loss resulting from the unique geometry of the acoustic crystal, but shift the resonant frequencies in opposite directions. In addition, when the convective effect and the eddy effect of the airflow, as well as the intrinsic interaction effect generated from the unique geometrical structure of the acoustic metamaterial cannot be ignored, they exhibit competition phenomena with each other, resulting in a widening of the resonance peak. As a result, these three effects cause the shift of the resonance frequency of the sound transmission loss and the widening of the resonance peak. The results of this study show that even in the case of turbulent flow, acoustic metamaterial can be used for transportation by properly controlling the geometric size and shape of the acoustic metamaterial.Comment: 19 pages, 17 figure

Electroactive Artificial Muscles Based on Functionally Antagonistic Core–Shell Polymer Electrolyte Derived from PS-b-PSS Block Copolymer

Electroactive ionic soft actuators, a type of artificial muscles containing a polymer electrolyte membrane sandwiched between two electrodes, have been intensively investigated owing to their potential applications to bioinspired soft robotics, wearable electronics, and active biomedical devices. However, the design and synthesis of an efficient polymer electrolyte suitable for ion migration have been major challenges in developing high-performance ionic soft actuators. Herein, a highly bendable ionic soft actuator based on an unprecedented block copolymer is reported, i.e., polystyrene-b-poly(1-ethyl-3-methylimidazolium-4-styrenesulfonate) (PS-b-PSS-EMIm), with a functionally antagonistic core–shell architecture that is specifically designed as an ionic exchangeable polymer electrolyte. The corresponding actuator shows exceptionally good actuation performance, with a high displacement of 8.22 mm at an ultralow voltage of 0.5 V, a fast rise time of 5 s, and excellent durability over 14 000 cycles. It is envisaged that the development of this high-performance ionic soft actuator could contribute to the progress toward the realization of the aforementioned applications. Furthermore, the procedure described herein can also be applied for developing novel polymer electrolytes related to solid-state lithium batteries and fuel cells

The Association between Disturbed Eating Behavior and Socioeconomic Status: The Online Korean Adolescent Panel Survey (OnKAPS)

Background: A limited amount of research, primarily conducted in Western countries, has suggested that higher socioeconomic status (SES) is associated with higher risk of eating disorders (EDs). However, little is known about this association in Asian countries. We examined the association of SES with disturbed eating behavior (DEB) and related factors in Korean adolescents. Subjects A nationwide online panel survey was conducted in a sample of adolescents (n = 6,943, 49.9% girls). DEB was measured with the 26-item Eating Attitudes Test (EAT-26). Participants who scored ≥20 on the EAT-26 were considered to have DEB. Participants’ SES was determined based on self-reported household economic status. Results: The prevalence of DEB was 12.7%: 10.5% among boys and 14.8% among girls. Both boys and girls with DEB were more likely to perceive themselves as obese, experience higher levels of stress, and have lower academic achievement. The risk for DEB was significantly higher in boys of higher SES than in those of middle SES (OR = 1.45, 95%CI = 1.05–1.99 for high SES; OR = 5.16, 95%CI: 3.50–7.61 for highest SES). Among girls, higher risk of DEB was associated with the highest and lowest SES (OR = 1.52, 95%CI: 1.13–2.06 for lowest SES; OR = 2.22, 95%CI: 1.34–3.68 for highest SES). Conclusions: Despite the lower prevalence of obesity in Korea compared with Western countries, the prevalence of DEB in Korean adolescents was high, especially among girls. Moreover, the association between SES and DEB followed a U-shaped curve for girls and a J-shaped curve for boys

Forage Rye Cultivars for Animal Feed in Korea

Rye (Secale cereal L.) is well known for its overwintering ability and has the highest tolerance to cold temperature of the small grain cereals such as wheat, barley, and oat. Rye is used as livestock pasture and as green manure in Korea, and its cultivation area for fodder is about 50,000 ha in 2014. Most rye is grown as a fall-sown annual crop, generally called “winter rye”. In Korea, rye cultivation for whole crop silage (WCS) in the winter-season rice field can be considered as a promising way to enhance feed supply. The WCS production can be an efficient way to use farm products as livestock feed, and it can also contribute to increasing farm income. Although rye is inferior in several ways to the predominant cereal crops (wheat, rice, and maize), it will continue to be an important crop for farmers in Korea because of its winter hardiness and early harvesting by rapid growing ability

Numb Chin Syndrome with Concomitant Painful Ophthalmoplegia Leading to a Diagnosis of Diffuse Large B Cell Lymphoma

Painful ophthalmoplegia (PO) and concomitant numb chin syndrome (NCS) is a very rare event. There are a few reports in the literature about PO and concomitant NCS that have preceded the diagnosis of a malignancy. In this report, we describe a patient with diffuse large B cell lymphoma who presented with PO and concomitant NCS as the initial symptom of the disease

HOXB13 promotes androgen independent growth of LNCaP prostate cancer cells by the activation of E2F signaling

<p>Abstract</p> <p>Background</p> <p>Androgen signaling plays a critical role in the development of prostate cancer and its progression. However, androgen-independent prostate cancer cells emerge after hormone ablation therapy, resulting in significant clinical problems. We have previously demonstrated that the HOXB13 homeodomain protein functions as a prostate cancer cell growth suppressor by inhibiting androgen-mediated signals. However, the role of the HOXB13 in androgen-independent growth of prostate cancer cells remains unexplained.</p> <p>Results</p> <p>In this report, we first demonstrated that HOXB13 was highly overexpressed in hormone-refractory tumors compared to tumors without prostate-specific antigen after initial treatment. Functionally, in an androgen-free environment minimal induction of HOXB13 in LNCaP prostate cancer cells, to the level of the normal prostate, markedly promoted cell proliferation while suppression inhibited cell proliferation. The HOXB13-mediated cell growth promotion in the absence of androgen, appears to be mainly accomplished through the activation of RB-E2F signaling by inhibiting the expression of the p21^waftumor suppressor. Indeed, forced expression of HOXB13 dramatically decreased expression of p21^waf; this inhibition largely affected HOXB13-mediated promotion of E2F signaling.</p> <p>Conclusions</p> <p>Taken together, the results of this study demonstrated the presence of a novel pathway that helps understand androgen-independent survival of prostate cancer cells. These findings suggest that upregulation of HOXB13 is associated with an additive growth advantage of prostate cancer cells in the absence of or low androgen concentrations, by the regulation of p21-mediated E2F signaling.</p

Fatal Biliary-Systemic Air Embolism during Endoscopic Retrograde Cholangiopancreatography: A Case with Multifocal Liver Abscesses and Choledochoduodenostomy

We report a rare case of a massive fatal embolism that occurred in the middle of endoscopic retrograde cholangiopancreatography (ERCP) and retrospectively examine the significant causes of the event. The patient was a 50-year old female with an uncertain history of previous abdominal surgery for multiple biliary stones 20 years prior. The patient presented with acute right upper quadrant pain. An abdominal computed tomographic (CT) scan revealed the presence of multiple stones in the common bile duct (CBD) and intra-hepatic duct (IHD) with biliary obstruction, multifocal liver abscesses, and air-biliarygram. Emergency ERCP showed a wide and straight opening of choledochoduodenostomy, which may have been created during a previous surgery, and multiple filling defects in the CBD. With the use of a forward endoscope, mud stones were extracted through the opening of the choledochoduodenostomy. Cardiac arrest suddenly developed during the procedure, and despite immediate resuscitation, the patient died due to a massive systemic air embolism. We reviewed previously reported fatal cases and accessed factors facilitating air embolisms in this case

Bowel Obstruction Caused by an Intramural Duodenal Hematoma: A Case Report of Endoscopic Incision and Drainage

Complications associated with an intramural hematoma of the bowel, is a relatively unusual condition. Most intramural hematomas resolve spontaneously with conservative treatment and the patient prognosis is good. However, if the symptoms are not resolved or the condition persists, surgical intervention may be necessary. Here we describe internal incision and drainage by endoscopy for the treatment of an intramural hematoma of the duodenum. A 63-yr-old woman was admitted to the hospital with hematemesis. The esophagogastroduodenoscopy (EGD) showed active ulcer bleeding at the distal portion of duodenal bulb. A total of 10 mL of 0.2% epinephrine and 2 mL of fibrin glue were injected locally. The patient developed diffuse abdominal pain and projectile vomiting three days after the endoscopic treatment. An abdominal computed tomography revealed a very large hematoma at the lateral duodenal wall, approximately 10×5 cm in diameter. Follow-up EGD was performed showing complete luminal obstruction at the second portion of the duodenum caused by an intramural hematoma. The patient's condition was not improved with conservative treatment. Therefore, 21 days after admission, endoscopic treatment of the hematoma was attempted. Puncture and incision were performed with an electrical needle knife. Two days after the procedure, the patient was tolerating a soft diet without complaints of abdominal pain or vomiting. The hematoma resolved completely on the follow-up studies