• Structural Engineering and Mechanics
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• v.84 no.3
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• pp.393-411
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• 2022

A high-performance reactive powder concrete (RPC) has been readied alongside river sand, with 1.25 mm particle size when under the condition of 80C steam curing. As a heat and sound insulation, expanded perlite aggregate (EPA) provides economic advantages in building. Concrete containing EPA is examined in terms of cement types (CEM II 32.5R and CEM I 42.5R), doses (0, 2%, 4% and 6%) as well as replacement rates in this research study. The compressive and density of concrete were used in the testing. At the end of the 28-day period, destructive and nondestructive tests were performed on cube specimens of 150 mm150 mm150 mm. The concrete density is not decreased with the addition of more perlite (from 45 to 60 percent), since the enlarged perlite has a very low barrier to crushing. To get a homogenous and fluid concrete mix, longer mixing times for all the mix components are necessary due to the higher amount of perlite. As a result, it is not suggested to use greater volumes of this aggregate in RPC. In the presence of de-icing salt, the lightweight RPC exhibits excellent freeze-thaw resistance (mass is less than 0.2 kg/m²). The addition of perlite strengthens the aggregate-matrix contact, but there is no apparent ITZ. An increased compressive strength was seen in concretes containing expanded perlite powder and steel fibers with good performance.

• Geomechanics and Engineering
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• v.31 no.1
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• pp.99-112
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• 2022

The present study examines the natural frequencies (NFs) of perfect/imperfect functionally graded sandwich beams (P/IP-FGSBs), which are composed of a porous core constructed of functionally graded materials (FGMs) and a homogenous isotropic metal and ceramic face sheets resting on elastic foundations. To accomplish this, the material properties of the FGSBs are assumed to vary continuously along the thickness direction as a function of the volume fraction of constituents expressed by the modified rule of the mixture, which includes porosity volume fraction represented using four distinct types of porosity distribution models. Additionally, to characterize the reaction of the two-parameter elastic foundation to the Perfect/Imperfect (P/IP) FGSBs, the medium is assumed to be linear, homogeneous, and isotropic, and it is described using the Winkler-Pasternak model. Furthermore, the kinematic relationship of the P/IP-FGSBs resting on the Winkler-Pasternak elastic foundations (WPEFs) is described using trigonometric shear deformation theory (TrSDT), and the equations of motion are constructed using Hamilton's principle. A closed-form solution is developed for the free vibration analysis of P/IP-FGSBs resting on the WPEFs under four distinct boundary conditions (BCs). To validate the new formulation, extensive comparisons with existing data are made. A detailed investigation is carried out for the effects of the foundation coefficients, mode numbers (MNs), porosity volume fraction, power-law index, span to depth ratio, porosity distribution patterns (PDPs), skin core skin thickness ratios (SCSTR), and BCs on the values of the NFs of the P/IP-FGSBs.

• Journal of the Korean Society of Radiology
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• v.83 no.3
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• pp.719-723
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• 2022

Rosai-Dorfman Disease (RDD) is a rare lymphoproliferative disease, and the occurrence of isolated intracranial RDD is extremely rare. Most cases of intracranial RDDs present as dural masses showing homogenous enhancement on MRI, which makes it difficult to differentiate these masses from meningiomas before surgery unless massive cervical lymphadenopathy is observed. We herein report a rare case of isolated intracranial RDD in a 65-year-old male. Brain MRI revealed a well-defined enhancing mass-like lesion involving the right frontal convexity and subtle diffusion restriction. However, only a subtle blush was observed on the preoperative cerebral angiogram. Although instances of isolated intracranial RDD are rare, it should be considered as a potential differential diagnosis when a dural mass with hypovascularity is visualized on the cerebral angiogram.

• Korean Journal of Head & Neck Oncology
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• v.40 no.1
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• pp.49-53
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• 2024

Dermatofibrosarcoma protuberans (DFSP) is a rare soft tissue sarcoma, with an incidence of about 0.8% to 5% per million people per year, accounting for 1% of soft tissue sarcomas. In its early stage, DFSP is typically found as a violet or pinkish macule or patch, and it can develop into a palpable mass with ulceration or bleeding. The standard treatment for DFSP is wide local excision of the tumor with a 2- to 3-cm negative margin, and radiation therapy or chemotherapy can be conducted with surgical treatment. A 35-year-old man had a palpable mass on the left side of his occipital scalp without color change, ulceration, or bleeding, which typically are present in malignancy. A magnetic resonance imaging (MRI) scan showed a 3-cm homogenous enhanced mass without adhesion between the scalp and the mass. Unexpectedly, a biopsy revealed the round mass to be DFSP. A wide excision and rotation of the scalp flap were performed. The patient recovered without any complications and received adjuvant radiotherapy at a dose of 60 Gray (Gy) for six weeks. There was no recurrence through six months of follow-up. Here we report this unique case of DFSP with atypical presentation.

• Clinical Endoscopy
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• v.56 no.4
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• pp.510-520
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• 2023

Background/Aims: We aimed to investigate (1) promising clinical findings for the recognition of focal type autoimmune pancreatitis (FAIP) and (2) the impact of endoscopic ultrasound (EUS)-guided tissue acquisition (EUS-TA) on the diagnosis of FAIP. Methods: Twenty-three patients with FAIP were involved in this study, and 44 patients with resected pancreatic ductal adenocarcinoma (PDAC) were included in the control group. Results: (1) Multivariate analysis revealed that homogeneous delayed enhancement on contrast-enhanced computed tomography was a significant factor indicative of FAIP compared to PDAC (90% vs. 7%, p=0.015). (2) For 13 of 17 FAIP patients (76.5%) who underwent EUS-TA, EUS-TA aided the diagnostic confirmation of AIPs, and only one patient (5.9%) was found to have AIP after surgery. On the other hand, of the six patients who did not undergo EUS-TA, three (50.0%) underwent surgery for pancreatic lesions. Conclusions: Homogeneous delayed enhancement on contrast-enhanced computed tomography was the most useful clinical factor for discriminating FAIPs from PDACs. EUS-TA is mandatory for diagnostic confirmation of FAIP lesions and can contribute to a reduction in the rate of unnecessary surgery for patients with FAIP.

• Restorative Dentistry and Endodontics
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• v.36 no.6
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• pp.490-497
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• 2011

Objectives: This study examined the effect of the uncured dentin adhesives on the bond interface between the resin inlay and dentin. Materials and Methods: Dentin surface was exposed in 24 extracted human molars and the teeth were assigned to indirect and direct resin restoration group. For indirect resin groups, exposed dentin surfaces were temporized with provisional resin. The provisional restoration was removed after 1 wk and the teeth were divided further into 4 groups which used dentin adhesives (OptiBond FL, Kerr; One-Step, Bisco) with or without light-curing, respectively (Group OB-C, OB-NC, OS-C and OS-NC). Pre-fabricated resin blocks were cemented on the entire surfaces with resin cement. For the direct resin restoration groups, the dentin surfaces were treated with dentin adhesives (Group OB-D and OS-D), followed by restoring composite resin. After 24 hr, the teeth were assigned to microtensile bond strength (${\mu}TBS$) and confocal laser scanning microscopy (CLSM), respectively. Results: The indirect resin restoration groups showed a lower ${\mu}TBS$ than the direct resin restoration groups. The ${\mu}TBS$ values of the light cured dentin adhesive groups were higher than those of the uncured dentin adhesive groups (p < 0.05). CLSM analysis of the light cured dentin adhesive groups revealed definite and homogenous hybrid layers. However, the uncured dentin adhesive groups showed uncertain or even no hybrid layer. Conclusions: Light-curing of the dentin adhesive prior to the application of the cementing material in luting a resin inlay to dentin resulted in definite, homogenous hybrid layer formation, which may improve the bond strength.

• Tuberculosis and Respiratory Diseases
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• v.42 no.4
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• pp.481-491
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• 1995

Background: Recently there has been a trend of an increasing incidence of mediastinal tuberculous lymphadenitis(MTL) in adults. MTL often cause bronchial stenosis or esophago-mediastinal fistula. In spite of effective treatment, it is difficult to cure. Moreover, relapse frequently occurs. Authors analyzed chest CT findings and clinical features of 29 cases with MTL Methods: 29 cases with MTL were retrospectively studied with the clinical and radiologic features from April 1990 to March 1995 Results: 1) A total of 29 cases were studied. 12 cases were male and 17 cases were female. The male to female ratio was 1:1.4 Mean age was 29 years old. The 3rd decade(45%) was the most prevalent age group 2) The most common presenting symptoms and signs were palpable neck masses(62%) followed by cough(59%) and sputum(38%) 3) Except in one case of MTL, all patients had coexisting pulmonary tuberculosis, cervical tuberculous lymphadenitis, endobronchial tuberculosis and tuberculous pleurisy. Among the coexisting tuberculous diseases, Pulmonary tuberculosis was the most common(76%) 4) On simple chest X-ray, mediastinal enlargement was noted in 21 cases(72%), but it was not noted in 8 cases(28%). The most frequently involving site was the paratracheal node in 16 cases(72%). Rt side predominence(73%) was noted 5) Patterns of node appearance on a postcontrast CT scan were classified into 3 types. There were 19 cases(30%) of the Homogenous type, 30 cases(47%) of the Central low density type and 15 cases(23%) of the Peripheral fat obliteration type. The most common type was the central low density type. The most common lymph node size was 1~2 cm(88%) 6) The most frequently involved site was the paratracheal node in 26 cases(89%) by chest CT. Rt side(63%) was predominant 7) 9 cases(43%) had complete therapy and most common treatment duration was 13 - 18 months. 12 cases(57%) had incomplete continuing antituberculous medication and half of the cases had been treated above 19 months. Conclusion: Chest CT findings of MTL showed central low density area and peripheral rim enhancement, so this characteristic findings could differentiate it from other mediastinal diseases and help a diagnosis of tuberculosis. In spite of effective antituberculous medication, it is difficult to cure. Moreover, relapse frequently occurs. Further studies will be needed of the clinical features and the treatment of MTL.

• Journal of Embryo Transfer
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• v.24 no.3
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• pp.151-157
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• 2009

Serial ultrasonography was conducted on Miniature Schnauzer bitches, on purpose to observe the ultrasonographic appearance of normal ovaries and ovarian structures during the estrous cycle. The size of ovaries was increased from $76.8{\pm}7.5mm^2(Mean{\pm}S.D)$ on Day-12 (Day-0=ovulation day) to $114.4{\pm}5.5mm^2$ on Day-8 and there was no significantly different between both ovaries. The ovaries were recognized by its proximity to the caudal renal pole and appeared moderately echogenic oval shape with a smooth contour. The size of follicles was increased from $8.1{\pm}4.5mm^2$ on Day-12 to $114.4{\pm}5.5mm^2$ on Day-0 and there was no significantly different between both ovaries. The number of follicles was increased from $2.8{\pm}0.7$ on Day-12 to $1.1{\pm}0.1$ on Day-0 and there was no significantly different between both ovaries. The follicles were small anechoic fluid-filled structures in early of proestrus, more increased, and indistinguished from each follicles in late of proestrus. The size of corpora lutea was increased from $19.3{\pm}2.1mm^2$ on Day-0 to $26.4{\pm}8.1mm^2$ on Day-8 and there was no significantly different between both ovaries. The number of corpora lutea was increased from $1.4{\pm}0.6$ on Day-0 to $2.9{\pm}0.4$ on Day-38 and there was no significantly different between both ovaries. The corpora lutea were small anechoic cavity and thin hyperechoic wall in early of diestrus, became more hyperechoic, and increased homogenous structures. The results of this study would be useful for differential diagnosis between normal and abnormal structures of ovaries.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.2
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• pp.43-47
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• 2016

This paper covers the study on the properties of $TiO_2$ film deposited by atomic layer deposition (ALD) using TTIP and water at various temperatures including the low temperature range of <$150^{\circ}C$. At low deposition temperature, ALD $TiO_2$ films showed uniform growth rate per cycle ($0.3{\AA}/cycle$), good uniformity, smooth surface, and homogenous amorphicity. They also showed good conformality of >80% on the trench structure with the high aspect ratio of up to 75. However, relatively high concentration of impurities (C~4-7 at%) in the film was observed due to low deposition temperature.

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.1
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• pp.57-61
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• 1994

The study was conducted at low lying areas in Pabna Sirajgong districts of Bangladesh. To observe the potentiality of bio-mass production two trials were conducted. In first trial maize intercropped with Khesari taking 15 experimental plots of each size $5m{\times}5m$ were arranged in 5 blocks having homogenous soil characteristics. The study showed that the bio-mass yield of sole maize and sole Khesari were 35.25 t/ha. and 56.80 t/ha. respectively and there was a significant difference (p < 0.01) among them. The results also showed that bio-mass yield of maize and Kherasi was higher ($70.04{\pm}6.25t/ha$, $98.88{\pm}10.77t/ha$ and $80.56{\pm}9.5t/ha$) compared to sole maize and sole Khesari and land equivalent ratio was also lower. For second trial, one hectare of land was divided into 16 experimental plots with 4 replications in each plot. Four levels of urea (0 kg/ha, 30 kg/ha, 45 kg/ha, and 60 kg/ha.) were applied to experimental plot. The seed rates were 98.8 kg/ha (farmer's practice), 86.45 kg/ha, 74.1 kg/ha and 61.75 kg/ha. average bio-mass yield of matikalai at different seed rates along with urea fertilizer ranged from 38.49 t/ha, to 65.35 t/ha. the highest seed rate along with highest fertilizer also correspond to the peak production (65.35 t/ha) and the lowest seed rate (61.75 kg/ha) along with the lowest fertilizer rate (30 kg/ha.) showed lowest production (38.49 t/ha.). Here, it was found that the bio-mass yield of matikalai increased with the incremental amount of seed, indicating significant effect (p < 0.05) of seed rates on the bio-mass yield of matikalai. On the other hand, fertilizer doses in different treatment combinations had significant effect (p < 0.05) on bio-mass yield. Two levels of seed rates at zero level of fertilizer were recommended : 86.45 kg/ha for the resource rich farmers and 61.75 kg/ha for the resource poor farmers.