Effect of few-walled carbon nanotube crystallinity on electron field emission property

We discuss the influence of few-walled carbon nanotubes (FWCNTs) treated with nitric acid and/or sulfuric acid on field emission characteristics. FWCNTs/tetraethyl orthosilicate (TEOS) thin film field emitters were fabricated by a spray method using FWCNTs/TEOS sol one-component solution onto indium tin oxide (ITO) glass. After thermal curing, they were found tightly adhered to the ITO glass, and after an activation process by a taping method, numerous FWCNTs were aligned preferentially in the vertical direction. Pristine FWCNT/ TEOS-based field emitters revealed higher current density, lower turn-on field, and a higher field enhancement factor than the oxidized FWCNTs-based field emitters. However, the unstable dispersion of pristine FWCNT in TEOS/N,N-dimethylformamide solution was not applicable to the field emitter fabrication using a spray method. Although the field emitter of nitric acid-treated FWCNT showed slightly lower field emission characteristics, this could be improved by the introduction of metal nanoparticles or resistive layer coating. Thus, we can conclude that our spray method using nitric acid-treated FWCNT could be useful for fabricating a field emitter and offers several advantages compared to previously reported techniques such as chemical vapor deposition and screen printing.ope

Clinical Characteristics of Renal Cell Carcinoma in Korean Patients with von Hippel-Lindau Disease Compared to Sporadic Bilateral or Multifocal Renal Cell Carcinoma

This study was done to analyze the clinical characteristics of renal cell carcinoma (RCC) in Korean patients with von Hippel-Lindau (VHL) disease. Between January 1996 and July 2008, 1,514 patients were diagnosed with RCC and 24 patients were diagnosed with VHL disease at our institute. We analyzed the clinical characteristics of the 24 patients diagnosed with VHL. The mean age of patients with VHL was 39.2±12.6 yr; the mean age of patients with both VHL and RCC was 42.5±10.3 yr. Among the 24 patients with VHL, 7 patients had retinal angiomas, 11 had RCC, 16 had renal lesions, 18 had pancreatic lesions and 21 had cerebellar hemangioblastomas. There was no significant difference between survival rates of patients with VHL alone and those with VHL and RCC. However, cancer-specific survival rates were significantly different between patients with both VHL and RCC and patients with sporadic bilateral or multifocal RCC. In our Korean study, the incidence of RCC in patients with VHL disease is 45.8% and the incidence of VHL disease in patients with RCC is 0.73%. Due to the low overall incidence of VHL in Korea, extended multi-institutional studies are needed to establish the true characteristics of VHL disease

Trends of Presentation and Clinical Outcome of Treated Renal Angiomyolipoma

PURPOSE: The purpose of this study is to set guidelines for the management of renal angiomyolipoma (AML), clinical prognosis according to tumor size, in association with tuberous sclerosis complex (TSC), multiplicity, radiographic finding, and treatment modality. MATERIALS AND METHODS: Between March 1998 and October 2008, 129 out of 254 patients with AML who underwent surgical intervention or angioembolization were enrolled. Diagnosis of AML was determined by the presence of a low attenuated component on CT imaging or by pathological confirmation. Indications of treatment were intractable pain, hematuria, suspicion of malignancy, large tumor size, spontaneous rupture, and radiographically equivocal tumors in which a differential diagnosis was needed to rule out malignancy. Parameters including age, sex, tumor size, multiplicity, radiographic characteristics, association with TSC, and treatment modality were reviewed. RESULTS: Age at presentation was 50.6 years and mean tumor size was 3.5 cm. Presentation symptoms were flank pain, hematuria, spontaneous rupture, and fatigue. 97 (75.2%) patients were incidentally discovered. 100 (77.5%) were females. 68 (52.7%) underwent nephron-sparing surgery (NSS), 35 (27.1%) radical nephrectomy, and 26 (20.2%) angioembolization. TSC was accompanied in 12 (9.3%) patients. No patient developed renal function impairment during the mean follow-up period of 64.8 months. Patients with TSC presented at a younger age, along with larger, bilateral, and multiple lesions. CONCLUSION: Significant differences in clinical manifestations and treatment outcomes were noted in respect to tumor characteristics, association with TSC, and treatment modality. Considering the benign nature of AML, these parameters ought to be considered when deciding upon active surveillance or prophylactic intervention.ope

Prevalence of Neuropathic Pain and Patient-Reported Outcomes in Korean Adults with Chronic Low Back Pain Resulting from Neuropathic Low Back Pain

Study DesignA noninterventional, multicenter, cross-sectional study.PurposeWe investigated the prevalence of neuropathic pain (NP) and patient-reported outcomes (PROs) of the quality of life (QoL) and functional disability in Korean adults with chronic low back pain (CLBP).Overview of LiteratureAmong patients with CLBP, 20%–55% had NP.MethodsPatients older than 20 years with CLBP lasting for longer than three months, with a visual analog scale (VAS) pain score higher than four, and with pain medications being used for at least four weeks before enrollment were recruited from 27 general hospitals between December 2014 and May 2015. Medical chart reviews were performed to collect demographic/clinical features and diagnosis of NP (douleur neuropathique 4, DN4). The QoL (EuroQoL 5-dimension, EQ-5D; EQ-VAS) and functional disability (Quebec Back Pain Disability Scale, QBPDS) were determined through patient surveys. Multiple linear regression analyses were performed to compare PROs between the NP (DN4≥4) and non-NP (DN4<4) groups.ResultsA total of 1,200 patients (females: 65.7%; mean age: 63.4±13.0 years) were enrolled. The mean scores of EQ-5D, EQ-VAS, and QBPDS were 0.5±0.3, 55.7±19.4, and 40.4±21.1, respectively. Among all patients, 492 (41.0%; 95% confidence interval, 38.2%–43.8%) suffered from NP. The prevalence of NP was higher in male patients (46.8%; p<0.01), in patients who had pain based on radiological and neurological findings (59.0%; p<0.01), and in patients who had severe pain (49.0%; p<0.01). There were significant mean differences in EQ-5D (NP group vs. non-NP group: 0.4±0.3 vs. 0.5±0.3; p<0.01) and QBPDS (NP group vs. non-NP group: 45.8±21.2 vs. 36.3±20.2; p<0.01) scores. In the multiple linear regression, patients with NP showed lower EQ-5D (β=−0.1; p<0.01) and higher QBPDS (β=7.0; p<0.01) scores than those without NP.ConclusionsNP was highly prevalent in Korean patients with CLBP. Patients with CLBP having NP had a lower QoL and more severe dysfunction than those without NP. To enhance the QoL and functional status of patients with CLBP, this study highlights the importance of appropriately diagnosing and treating NP

Analysis of Navigator Decision Making through Cognitive Science for the Presentation of a Collision-Avoidance Algorithm for MASSs

The study of navigator behavior is important for the study of MASSs. This study analyzed navigator behavior through cognitive science, and it modeled the navigator decision-making process. Usually, the assessment of the collision risk for long-distance target ships is conducted through the distance (DCPA) and time (TCPA) to the closest point of approach. The navigator’s decision-making process is carried out quantitatively based on numerical values. Although the angle of the rudder is presented as a numerical value (i.e., 5°, 10°, 15°, and so on), it is expected that the navigator’s use of the rudder will depend on the conventional method rather than the quantitative one. Therefore, a scenario was constructed, and a simulation test was carried out through a ship-handling simulator. Our results confirmed that the rudder was used according to the conventional method. Moreover, the navigator decision-making process was analyzed through cognitive science. Cognitive science has revealed that human judgment is not logical, and that all decision making relies on memory. We identified the type of memory that affects the decision making of navigators: the DCPA and navigators’ decision-making-criteria values were mainly formed by episodic memory. A decision-making model for the relationship between the navigator’s episodic memory and the value of the DCPA was subsequently developed. This study took a scientific approach to analyze the process of the decision making of navigators, and an engineering approach to construct a decision-making model for application in MASSs

SASD Modeling Using an ANFIS to Prevent the Collision of MASS in Restricted Areas

This study aimed to present the criteria for the collision avoidance of maritime autonomous surface ships (MASS) in restricted areas. The criteria were presented via ship domains, and a seafarers’ awareness-based ship domain (SASD) that dynamically changes the existing SASD according to the external environment was used to develop a new domain model. For application, we have converged an adaptive neuro-fuzzy inference system with the existing model. The proposed SASD was applied to an actual marine restricted area and compared with automatic identification system (AIS) based ship domain models. Consequently, although there was a slight difference depending on the restricted area and domain design method applied, the SASD, (i.e., the minor axis of the elliptical domain) and the AIS-based ship domain were similar. Cross-validation of the seafarers’ awareness-based ship domain and the AIS-based ship domain could propose a reference lateral side passing distance for MASS in restricted areas. However, the major axis of the ellipse should be further studied since the domain design method differs between models

SASD Modeling Using an ANFIS to Prevent the Collision of MASS in Restricted Areas

This study aimed to present the criteria for the collision avoidance of maritime autonomous surface ships (MASS) in restricted areas. The criteria were presented via ship domains, and a seafarers&rsquo; awareness-based ship domain (SASD) that dynamically changes the existing SASD according to the external environment was used to develop a new domain model. For application, we have converged an adaptive neuro-fuzzy inference system with the existing model. The proposed SASD was applied to an actual marine restricted area and compared with automatic identification system (AIS) based ship domain models. Consequently, although there was a slight difference depending on the restricted area and domain design method applied, the SASD, (i.e., the minor axis of the elliptical domain) and the AIS-based ship domain were similar. Cross-validation of the seafarers&rsquo; awareness-based ship domain and the AIS-based ship domain could propose a reference lateral side passing distance for MASS in restricted areas. However, the major axis of the ellipse should be further studied since the domain design method differs between models