A combination of a series of epoxy coatings filled with octadecylamine (ODA)-modified graphene oxide (mGO) or commercial exfoliated graphite nanoplatelets (xGnP) was developed to boost the anticorrosion performances of mild steel substrates in acidic and NaCl aqueous solutions. The xGnP and mGO were applied successfully as fillers for the preparation of layer by layer (LBL) xGnP or mGO/epoxy coatings, respectively, which were coated on the clean steel surfaces to form LBLassembled layers. The LBL-assembled xGnP or mGO/epoxy coating-coated steel substrates exhibit excellent anticorrosion performances. The corrosion potentials (Ecorr) of xGnP-1/xGnP-2/3 and mGO-1/mGO-2/3 display at − 193 and − 150 mV, respectively, while Ecorr of the bare steel shows at − 871 mV of immersion in the 3.5 wt% NaCl solution. The most positive Ecorr values are obtained for xGnP-1/2/3 (− 117 mV) and mGO-1/2/3 (− 66 mV), showing the best anticorrosion performances compared to the bare steel (− 404 mV) in 17 wt% HCl solution.
Activated carbon fibers (ACFs) were treated by electroless plating of CuO to improve their removal performance for volatile organic compounds (VOCs). The properties of these samples(CuO@ACFs) were evaluated by X-ray photoelectron spectroscopy (XPS), BET and N2O chemisorption to determine the area and dispersion of metallic CuO. The removal efficiency for benzene was investigated by gas chromatography (GC). The breakthrough time of CuO@ACFs increased by approximately 120% compared to that of untreated ACFs at benzene of 100 ppm. CuO@ACFs removed 100% of the benzene in 20 h, indicating this material can be used as a removal technology for VOCs.
Since a cluster of pneumonia cases of unknown etiology was first reported in China in December 2019, the number of confirmed cases with coronavirus disease 2019 (COVID-19) (caused by severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2]) worldwide has been increasing, and nearly two million patients are expected to have died by February 2021. Globally, COVID-19 is being considered a primary pulmonary disease, but it is more than a lung infection. This is because patients infected with SARS-CoV-2 present with a variety of clinical signs and symptoms involving many organs, ranging from fever, inflammation, myocardial injury, shock, and the development of coronary artery aneurysm. SARS-CoV-2 shows unique characteristics in its transmission, mortality, and stability in different environmental conditions. During COVID-19 pandemic, about 10 drugs have been clinically tried with none proven to be effective. With no prospect for effective drugs in the near future, there are currently possibilities of success with vaccines and convalescent plasma. Along with the prospect of vaccines and other therapeutic drugs, special precautions (isolation, testing, treating, and tracing) are strictly recommended until we return to normal situations. In this review we comprehensively analyzed the clinical presentations, characteristics, and outcomes of patients with COVID-19, and tried to assess the clinical effects of some drugs as part of the ongoing efforts to understand COVID-19 pandemic.
To enhance mechanical properties through improvement of dispersion stability of carbon black (CB) in epoxy resins, fluorine functional groups were introduced on the CB surface by fluorination. The changes in the chemical properties and dispersion stabilities after fluorination were evaluated with different partial pressures of fluorine gas. The mechanical properties of the fluorinated CB/epoxy composites were evaluated by the test of tensile, impact strengths and creep behavior. The fluorinated CB/epoxy composites showed approximately 1.6 and 1.1 times enhancement in the tensile and impact strengths compared to that of neat epoxy, respectively. Moreover, when a constant load was applied at 323 K, the fluorinated CB/epoxy composites lasted longer and had smaller strain changes than those of the raw CB/epoxy composites. Thus, well-dispersed CB by fluorination in epoxy resins effectively transfers mechanical stress.
Persistent left cranial vena cava (PLCVC) is a remnant vessel connected with the coronary sinus and draining into the right atrium. A 3-month-old intact male Bichon Frise was evaluated for the presence of a mechanical murmur auscultation in the local animal hospital. No significant clinical signs were present on physical examination except mechanical murmur. Patent ductus arteriosus (PDA) was diagnosed in the imaging procedure. During the left thoracotomy, PLCVC was found. The vascular malformation made the surgical process difficult by hiding PDA from the left thoracotomy surgical view. PLCVC and the vagus nerve was carefully dissected and lifted to secure a clear surgical view of PDA. The ductus arteriosus was ligated. Computed tomography angiography (CTA) was performed postoperatively. On CTA, left brachiocephalic vein retaining connection with the coronary sinus draining into the right atrium was observed. CTA is highly recommended for dogs with PDA to provide better postoperative results.
The baculovirus-insect cell expression system has been widely used method for the recombinant protein expression. The present study has several limitation. In this study, we constructed vectors consisting of transcriptional enhanced factor and promoter that improve the expression level. To confirm the usefulness of these vector system, Human papillomavirus (HPV) VLPs have been expressed by baculovirus hyper expression system. HPV VLPs were purified using a CaptoTM Core 700 (GE Healthcare Life Sciences) chromatography approach. Baculovirus hyper expression system production efficiency was influenced by the HPV VLPs production. HPV VLPs vaccination to BALB/c mice induced the generation of antibody confirmed by ELISA. This study could provide improvements on the vaccine production for the development of VLP vaccines high expression of useful heterologous proteins.
PURPOSES : Thermal cracking (also called low-temperature cracking) is a serious stress for asphalt pavement, especially in eastern South Korea, the northern USA, and Canada. Thermal cracking occurs when the level of thermal stress exceeds the corresponding level of low temperature strength of the given asphalt materials. Therefore, computation of thermal stress is a key factor for understanding, quantifying, and evaluating the level of low-temperature cracking resistance of asphalt pavement. In this paper, two different approaches for computing thermal stress on asphalt binder were introduced: Hopkins and Hamming’s algorithm (1967) and the application of a simple power-law function. All the computed results were compared visually; then the findings and recommendations were discussed.
METHODS: Thermal stress of the tested asphalt binder was computed based on the methodology introduced in previous literatures related to viscoelastic theory. To perform the numerical analysis, MATLABTM 2D matrix-correlation and Microsoft Excel visual basic code were developed and used for the function fitting and value-minimization processes, respectively.
RESULTS : Different results from thermal stress were observed with application of different computation approaches. This variation of the data trends could be recognized not only visually but also statistically.
CONCLUSIONS: It can be concluded that these two different computation approaches can successfully provide upper and lower limits (i.e. boundaries) for thermal stress prediction of a given asphalt binder. Based on these findings, more reliable and reasonable thermal stress results could be provided and finally, better pavement performance predictions could also be expected.
우드펠렛은 가정용, 상업용, 산업용 등으로 사용되며 특히 화력발전소에서 석탄 대용으로 수입량이 급증하여 연간 약 2,400만톤 가량 수입되고 있는 상황이다. 우드펠렛 검역훈증제로 기존에는 메틸브로마이드(이하 MB)가 최근까지 사용되어져 왔으나, MB의 높은 흡착률과 우드펠렛의 과도한 수용비로 인해 최종가스농도 기준에 미치지 못하여 재투약하는 사례가 빈번히 발생해 문제가 되어져왔다. 이를 해결하기 위해 농림축산검역본부에서는 올해 초 MB와 포스핀을 병행으로 처리하는 방식의 소독처리기준을 신설하였다. 새로운 소독처리기준이 설정됨에 따라 배기시 안전한 배기시간 수준을 설정하기 위해 병행처리 후 수착과 탈착되는 가스농도를 조사하였다.
실내 훈증상에 우드펠렛을 채우고 약제 처리한 결과 각 훈증제의 TLV(Threshold Limit Value)-TWA(Time Weighted Average) 기준이하로 농도가 감소되는 배기시간은 25℃일 때 MB는 120시간, 포스핀은 6시간으로 측정되었고 15℃일 때 MB는 186시간, 포스핀은 19시간으로 측정되었다.
The ride quality (i.e. smoothness) is a key factor for evaluating the construction quality of expressway asphalt pavement. Conventionally, three paving devices are widely used to control the surface layer thickness: leveling sensor (i.e. LS), short-range-surfacing-contact-ski (i.e. SSCS) and long-range-surfacing-contact-ski (i.e. LSCS). However, each of these levelling tools presents one major drawback. In the case of LS, if the original sub-layer evenness is poor, the final asphalt pavement surface and its smoothness will be negatively affected. The SSCS cannot assure satisfactory smoothness when relatively long paving section (in the order of 10 km) are paved. While the LSCS would reduce the drawback of the SSCS, its weight on the one hand and its length on the other discourage its use in the paving site especially for curved sections. In this paper, a next generation pavement smoothness leveling equipment, known as non-contact-digital-ski (i.e. NCDS) was implemented, evaluated and compared to the conventional equipment leveling device. The international Roughness Index (IRI m/km) was measured on sections paved with and without NCDS and the results visually and statistically compared. In addition, for the same sections, the modulus of the pavement layers was computed and compared by means of Falling Weight Deflectometer (i.e. FWD). It was observed that when NCDS is used for asphalt pavement overlay of existing concrete pavement, significant improvement in IRI (i.e. IRI<1.0m/km) and consistently uniform elastic modulus could be achieved compared to the conventional levelling and paving method.
박물관, 기록원 등의 주요 소독약제인 메틸브로마이드(MB)와 Ethylene Oxide(EO)는 오존층 파괴 물질 및 1급 발암물질로 규제가 되고 있어 대체 훈증제 개발이 필요한 실정이다. 따라서, 친환경 약제인 검역훈증제 에틸포메이트 (베이퍼메이트®)의 적용가능성을 확인하고자 주요 해충인 독일바퀴(Blatella germanica) 및 흰개미(Reticulitermes speratus)를 대상으로 Dose response 실험을 실시하였다. 공시충은 팜한농 작물보호연구센터 곤충사육실에서 누대사육중인 개체를 사용하였으며, 데시게이터(6.9L)에 농도별로 24시간동안 밀폐 훈증처리하여 약효를 조사하였다. 통계분석은 Probit analysis 통해 L(Ct) (Lethal Concentration x Time, gꞏhꞏm3)값을 산출하였다. 시험결과 L(Ct)50 및 L(Ct)99 값은 독일바퀴(혼합태)의 경우 48.38 및 346.34 gꞏhꞏm3 흰개미(성충)은 14.91및 660.94 gꞏhꞏm3로 나타났다. 모두 방제가 가능한 L(Ct)99 값은 660.94 gꞏhꞏm3으로 이는 에틸포메이 트 28.2 g/m3(베이퍼메이트® 170 g/m3)를 24시간 처리시 완전 방제가 가능할 것으로 판단된다.
Near infrared spectroscopy (NIRS) is a rapid and accurate method for analyzing the quality of cereals, and dried animal forage. However, one limitation of this method is its inability to measure fermentation parameters in dried and ground samples because they are volatile, and therefore, respectively lost during the drying process. In order to overcome this limitation, in this study, fresh coarse haylage was used to test the potential of NIRS to accurately determine chemical composition and fermentation parameters. Fresh coarse Italian ryegrass haylage samples were scanned at 1 nm intervals over a wavelength range of 680 to 2500 nm, and optical data were recorded as log 1/reflectance. Spectral data, together with first- and second-order derivatives, were analyzed using partial least squares (PLS) multivariate regressions; scatter correction procedures (standard normal variate and detrend) were used in order to reduce the effect of extraneous noise. Optimum calibrations were selected based on their low standard error of cross validation (SECV) values. Further, ratio of performance deviation, obtained by dividing the standard deviation of reference values by SECV values, was used to evaluate the reliability of predictive models. Our results showed that the NIRS method can predict chemical constituents accurately (correlation coefficient of cross validation, R2 cv, ranged from 0.76 to 0.97); the exception to this result was crude ash (R2 cv = 0.49 and RPD = 2.09). Comparison of mathematical treatments for raw spectra showed that second-order derivatives yielded better predictions than first-order derivatives. The best mathematical treatment for DM, ADF, and NDF, respectively was 2, 16, 16, whereas the best mathematical treatment for CP and crude ash, respectively was 2, 8, 8. The calibration models for fermentation parameters had low predictive accuracy for acetic, propionic, and butyric acids (RPD < 2.5). However, pH, and lactic and total acids were predicted with considerable accuracy (R2 cv 0.73 to 0.78; RPD values exceeded 2.5), and the best mathematical treatment for them was 1, 8, 8. Our findings show that, when fresh haylage is used, NIRS-based calibrations are reliable for the prediction of haylage characteristics, and therefore useful for the assessment of the forage quality.
Porcine spermatogonial stem cells (SSCs) prefer three-dimensional (3D) culture systems to 2D ones for the maintenance of self-renewal. Of the many 3D culture systems, agar-based hydrogels are candidates for supporting porcine SSC self-renewal, and there are various types of agar powder that can be used. In this study, we sought to identify an agar-based 3D hydrogel system that exhibited strong efficacy in the maintenance of porcine SSC self-renewal. First, 3D hydrogels with different mechanics were prepared with various concentrations of Bacto agar, lysogeny broth (LB) agar, and agarose powder, and the 3D hydrogel with the strongest alkaline phosphatase (AP) activity and greatest increase in colony size was identified for the different types of agar powder. Second, among the porcine SSCs cultured in the different 3D hydrogels, we analyzed the colony formation, morphology, and size; AP activity; and transcription and translation of porcine SSC-related genes, and these were compared to determine the optimal 3D hydrogel system for the maintenance of porcine SSC self-renewal. We found that 0.6% (w/v) Bacto agar-, 1% (w/v) LB agar-, and 0.2% (w/v) agarose-based 3D hydrogels showed the strongest maintenance of AP activity and the most pronounced increase in colony size in the culture of porcine SSCs. Moreover, among these hydrogels, the strongest transcription and translation of porcine SSC-related genes and largest colony size were detected in porcine SSCs cultured in the 0.2% (w/v) agarose-based 3D hydrogel, whereas there were no significant differences in colony formation and morphology. These results demonstrate that the 0.2% (w/v) agarose-based 3D hydrogel can be effectively used for the maintenance of porcine SSC self-renewal.