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Background Tofacitinib is a small molecule which inhibits janus kinase and has been shown to be effective for patients with active ulcerative colitis (UC). We investigated the real-life therapeutic effectiveness and safety of tofacitinib treatment for Korean patient with UC. Methods We retrospectively analyzed the data of patients with UC who received tofacitinib treatment at 10 hospitals in Korea. The primary outcome was clinical remission at week 16 which was defined as a partial Mayo score ≤2 with a combined rectal bleeding subscore and stool frequency subscore ≤1. The secondary outcome was endoscopic remission (Mayo endoscopic subscore ≤1) at week 16. Adverse events including herpes zoster and deep vein thrombosis were also evaluated. Results Between January 2018 and November 2020, a total of 123 patients with UC received tofacitinib treatment (Table 1). Clinical effectiveness was evaluated for those who had completed or stopped the tofacitinib therapy by week 16, week 24 and week 52, respectively (Figure 1). Clinical remission and response rates at week 16 were 65.3% and 73.7%, respectively (Figure 2A). Ninety-one out of 123 patients (74.0%) were followed up to week 52. Their clinical remission and response rates at week 52 were 49.5% and 58.2%, respectively (Figure 2A). Among 117 patients with baseline Mayo endoscopic subscore ≥2, endoscopic remission rate at week 16 was 55.6% (Figure 2C). Any adverse events occurred in 15 patients (12.2%) and serious adverse events occurred in 9 patients (7.3%). Herpes zoster occurred in 4 patients (3.3%) and one patient (0.8%) suffered from deep vein thrombosis (Table 2). Conclusion Tofacitinib was effective with an acceptable safety profile for Korean patients with UC in the real world.

Resistance spot welding, which is the dominant welding process with high productivity for manufacturing car body and other components, is widely used to weld various steel sheets in automotive industry. However, electrode indentation affects both the surface quality and mechanical property of resistance spot welded lap joint. Variation in the tip diameter of upper electrode and use of copper plate at the lower electrode side are an effective recourse to get sound surface appearance with reduced indentation depth due to lower current intensity. In present study, with 10 mm thick copper plate on lower electrode side, resistance spot welding of 1.2 and 1.6 mm thick cold rolled steel sheets has been performed to examine the effect of upper electrode tip diameter on formation of indentation depth and nugget diameter. The result exhibits that larger electrode tip diameter significantly reduced indentation depth on optimal nugget size corresponding to Korean Industrial Standard requirements for resistance spot welding. In case of welding in 1.2 mm thick steel sheets using electrode tip diameter of 8 mm, nugget diameter increased with increasing welding current and then the maximum tensile shear load was 6.55 kN under welding current of 10 kA. The maximum tensile shear load of 1.6 mm thick steel sheets reached 11.28 kN under welding current of 11 kA.

Background Anti-tumor necrosis factor (TNF) treatment for inflammatory bowel disease (IBD) increases the risk of tuberculosis (TB) infection. In the present study, we analyzed the clinical characteristics and risks of TB in Korean patients with IBD who received anti-TNF treatment. Methods The study included patients with IBD who were treated using anti-TNF agents between January 2001 and June 2018 at the Asan Medical Center. Overall, 1434 patients with ulcerative colitis or Crohn’s disease were enrolled. We calculated the incidence of active TB infection after anti-TNF treatment and compared the clinical characteristics of the TB group with those of the non-TB group. Results Twenty-one patients (1.46%) developed active TB infection, and the incidence rate of active TB was 366.73 per 100,000 person-years. In total, 198 patients (14.9%) were positive for latent tuberculosis infection (LTBI), of whom only eight (4%) did not complete LTBI treatment. The age at which the anti-TNF therapy was started was significantly higher in the TB group than in the non-TB group (HR 1.041, 95% CI 1.014–1.069, p = 0.002), and as age increased, so did the incidence rate of active TB infection (linearity p p = 0.862). Conclusions In patients with IBD, the incidence rate of TB increased with age at anti-TNF therapy initiation. Active treatment of LTBI may lower the incidence of TB in patients with IBD who are to undergo anti-TNF therapy.

The physics of vacuum arc spot operation remains subject of research due to difficulties associated with short characteristic times (ns to μs) and short length scales (μm or even smaller). The advancement of modern plasma diagnostic technologies may allow us to probe arc spot plasma with higher spatial and temporal resolution than before. In this contribution, we report on the evolution of arc spots using a steered arc plasma source which is in its construction similar to a linear sputtering magnetron: the E x B field is utilized to have some control of spot locations while performing the study. The main plasma diagnostics tool we employ is a streak camera with an image intensifier which allows us to observe the dynamics of the optical emission of arc spots in various sweep time intervals (50 μs, 10 μs, 1 μs, and 500 ns). The observed spot shows self-similar patterns in the emitted light with different sweep times.

Introduction: Immunomodulators remain fundamental for the medical treatment of Crohn’s disease (CD). Methotrexate (MTX) is widely used as a second-line immunomodulator; however, there is a lack of recent data on MTX monotherapy among the Asian population with CD. Therefore, in this study, we aimed to investigate the tolerability and clinical outcomes of MTX in Korean patients with CD. Methods: A retrospective chart review was performed for CD patients treated with MTX monotherapy or in combination with 5-aminosalicylic acid (5-ASA), at the Asan Medical Center, Seoul, South Korea. The tolerability of MTX monotherapy within 6 months was assessed and the clinical effectiveness of MTX was evaluated based on the Crohn’s disease activity index (CDAI). Results: In total, 85 patients were included, of which 29 (34.1%) discontinued MTX due to intolerability during the follow-up. Adverse events (AEs) were reported in 41 (48.2%) patients. The most common AE was gastrointestinal disorders (17/41) and only one patient experienced a serious AE, a systemic infection that required hospitalization. Among the 56 patients who tolerated MTX within 6 months, 44 (65.9%) showed a clinical response. Moreover, no factor was significantly associated with intolerability. The administration method was the only factor significantly associated with a response to MTX ( p = 0.041). The adjusted odds ratio of parenteral injection compared to oral administration was 5.68 (95% confidence interval (CI), 1.07–30.08). Conclusion: In this study, one-third of patients were intolerant to MTX; nonetheless, the response rate was as high as 65.9% among tolerant patients. In addition, no significant factors affected intolerability. In terms of the clinical response, parenteral injection could be better than oral administration.

The phase velocity of the wakefield of a laser wakefield accelerator can, theoretically, be manipulated by shaping the longitudinal plasma density profile, thus controlling the parameters of the generated electron beam. We present an experimental method where using a series of shaped longitudinal plasma density profiles we increased the mean electron peak energy more than 50%, from 175 ± 1 MeV to 262 ± 10 MeV and the maximum peak energy from 182 MeV to 363 MeV. The divergence follows closely the change of mean energy and decreases from 58.9 ± 0.45 mrad to 12.6 ± 1.2 mrad along the horizontal axis and from 35 ± 0.3 mrad to 8.3 ± 0.69 mrad along the vertical axis. Particle-in-cell simulations show that a ramp in a plasma density profile can affect the evolution of the wakefield, thus qualitatively confirming the experimental results. The presented method can increase the electron energy for a fixed laser power and at the same time offer an energy tunable source of electrons.

To improve the interfacial strength between basalt fibers (BFs) and PA6,6, amino-silane coupling agents were applied to BF-reinforced polyamide 6,6 composites. The effects of their molecular structures, especially the number of amino groups and the corresponding chain lengths, on the mechanical properties of basalt fiber-reinforced PA6,6 composites (BFRP) were then investigated. The results showed that even with the same type of silane coupling agent, the distinctive feature in its molecular structure is eventually displayed in the difference in the reinforcing mechanism to strengthen the interphase between BF and PA6,6, and consequently, its impact on the strength of the composites. The adhesive properties of BF to PA6,6 were promoted by the polar amino groups as well as the non-polar long CH2 chains of the silane coupling agents introduced to the BF surface. As the number of polar amino groups increased, the intermolecular hydrogen bonding with the CONH groups in PA6,6 increased, thus leading to enhanced interfacial adhesion between BF and PA6,6. The interfacial adhesion was also improved by the physical cross-linking formed from the chain entanglement between the silane molecules and PA6,6 as the number of non-polar long CH2 chains of the silane coupling agents increased. The tensile strength of their composites showed similar interfacial shear strength tendencies between BF and PA6,6 in the order of long-chain-, tri-, di-, and mono-amino-silane-treated BFRPs. Long-chain amino-silane was shown to be the most effective in strengthening the interphase between BF and PA6,6. This is because long-chain amino-silane induces strong chemical and physical bonding with PA6,6 as it has a large amount of amino groups in the terminate part and long CH2 chains in the spacer part.

Laser wakefield accelerators rely on relativistically moving micron-sized plasma cavities that provide extremely high electric field >100GV/m. Here, we demonstrate transverse shaping of the plasma cavity to produce controlled sub-GeV electron beams, adopting laser pulses with an axially rotatable ellipse-shaped focal spot. We showed the control capability on electron self-injection, charge, and transverse profile of the electron beam by rotating the focal spot. We observed that the effect of the elliptical focal spot was imprinted in the profiles of the electron beams and the electron energy increased, as compared to the case of a circular focal spot. We performed 3D particle-in-cell (PIC) simulations which reproduced the experimental results and revealed dynamics of a new asymmetric self-injection process. This simple scheme offers a novel control method on laser wakefield acceleration to produce tailored electron beams and x-rays for various applications., 5 pages, 5 figures

Background We investigated the real-life effectiveness and safety of vedolizumab maintenance treatment among Korean patients with Crohn’s disease (CD) or ulcerative colitis (UC) who previously failed anti-tumour necrosis factor (anti-TNF) therapy. Methods Adult patients with CD or UC who have previously failed anti-TNF therapy and received vedolizumab were prospectively enrolled from 16 hospitals in Korea. The primary outcome was clinical remission at week 54. Clinical remission was defined as a Crohn’s disease activity index (CDAI) Results Between August 2017 to July 2020, a total of 165 patients (81 with CD and 84 with UC) received vedolizumab therapy, of whom 154 patients (93.3%) (75 with CD and 79 with UC) received vedolizumab maintenance therapy (Table 1). Clinical remission and response rates at week 54 were 22.2% and 24.1% among patients with CD and 41.4% and 45.7% among patients with UC, respectively (Figure 1A and 1B). Among 70 patients with UC with baseline Mayo endoscopic subscore ≥2, endoscopic remission (Mayo endoscopic subscore ≤1) at week 54 was observed in 19 patients (27.1%). Out of 50 patients with CD with ulcers in baseline endoscopy, 2 patients (4%) showed a disappearance of ulcers at week 54 (Figure 1C). In the multivariable analysis, age at baseline (adjusted odds ration [aOR] 1.065, 95% confidence interval [CI] 1.003–1.131, P=0.041) and Mayo endoscopic subscore at baseline (aOR 0.141, 95% CI 0.026–0.746, P=0.021) were significantly associated with clinical remission at week 54 among patients with UC (Table 2). No factors were found to be associated with clinical remission at week 54 among patients with CD. Among patients who experienced one or more adverse events (n=134, 81.2%), serious adverse events occurred in 82 patients (49.7%) (Table 3). Disease exacerbation was the most common adverse events (n=89, 53.9%). Conclusion The real-life effectiveness of vedolizumab maintenance treatment for Korean patients with UC who failed anti-TNF therapy was generally similar with the outcomes reported from the previous Western studies. A substantial proportion of patients with CD experienced a loss of response during the first year of treatment. Less severe disease at baseline was associated with clinical remission at 1 year of vedolizumab therapy among patients with UC.

To ensure the safety of Kimchi, the safety of Napa cabbage is the most important. Contaminated irrigation water can be a major cause of pathogens during growth of Napa cabbage. The purpose of this study was to investigate the microbial quality of irrigation water used in the cultivation of Napa cabbage. A total of 111 samples including surface water (n = 75) and groundwater (n = 36) collected from four different regions in Korea where Napa cabbage is intensively cultivated were analyzed for a fecal indicator (Escherichia coli) Moreover, 164 E. coli isolates from irrigation water were investigated for pathogenic characteristics including antibiotic resistance, pathogenic genes, serotype, and toxicity using Caenorhabditis elegans. E. coli was detected in 96% of surface water samples and 25% of groundwater samples. The level of E. coli in surface water (0.2–3.2 log MPN/100 mL) was higher than that in groundwater (0–2.0 log MPN/100 mL). When the 164 E. coli isolates were investigated concerning antibiotic resistance, resistance rates were 11.0%, 2.4%, 3.0%, 1.8%, 2.4%, 4.3%, and 3.0% for ampicillin, ampicillin/sulbactam, cefazolin, cefoxitin, gentamicin, levofloxacin, and trimethoprim/sulfamethoxazole, respectively. In addition, 10 (6.1%) of the isolates were positive for the eaeA gene, indicative of enteropathogenic E. coli. Eight of these 10 isolates were obtained from the surface water of the mountainous region II and were toxic to C. elegans. The results indicate the need to manage the microbial risk of irrigation water to enhance the safety of cultivated Napa cabbage.

Oxide supports often play a critical role in metal-supported catalysts owing to their charge transfer phenomena that can alter catalytic performance. Herein, in place of conventional bulk oxide supports, monodisperse oxide nanoparticles (NPs) were exploited as supports for Pt catalysts. Depending on the type of oxide NP, Pt/oxide layered catalysts exhibited dramatic changes in the catalytic activity and selectivity for methanol oxidation. While Pt NPs deposited on MnO, Fe3O4, Co3O4, Cu2O, and ZnO NPs had comparable turnover frequencies to that of the pure Pt NP catalyst, Pt deposited TiO2 NPs changed the reaction rate significantly, with preferential selectivity observed toward partial oxidation products. Facet-specific interactions between Pt and TiO2 NPs were demonstrated by density functional theory calculations and catalytic reactions using shape-controlled TiO2 NPs. When Pt NPs were attached to spherical and rhombic TiO2 NPs with abundant (001) surfaces, methanol conversion was enhanced 10-fold owing...

Background In June 2015, a local public health laboratory was notified that students had developed gastroenteritis symptoms after attending a camp. An outbreak investigation was conducted to determine the extent and cause of the outbreak. Method A retrospective cohort study was conducted to determine the correlations between the illness and specific exposures at the school camp. All attendees were interviewed with a standard questionnaire that addressed clinical symptoms, food consumption, and environmental exposures. Clinical specimens were cultured using standard microbiological methods for bacterial and viral pathogens. The genetic relationships of all isolates were determined using pulsed-field gel electrophoresis (PFGE). Results A total 188 patients with symptoms of diarrhoea, abdominal pain, and nausea were identified. The completed questionnaires suggested that the consumption of drinking water was likely to be linked to this outbreak. Using microbiological methods, enterohaemorrhagic Escherichia coli , enteropathogenic E. coli , and enteroaggregative E. coli were isolated, and the isolates from both patient stool and environmental water samples displayed indistinguishable XbaI -PFGE patterns. The water system in the camp used groundwater drawn from a private underground reservoir for cooking and drinking. The environmental investigation revealed some problems with the water supply system, such as the use of inappropriate filters in the water purifier and a defect in the pipeline between the reservoir and the chlorination device. Conclusions This outbreak points to the importance of drinking water quality management in group facilities where underground water is used and emphasizes the need for periodic sanitation and inspection to prevent possible waterborne outbreaks.

Cathode spots in a magnetically steered arc source were studied under low-pressure noble gas (Ar) and reactive gas (N2, O2) atmospheres. The plasma was observed using a streak camera coupled with a long-distance microscope to study the evolution of cathode spots with high temporal and spatial resolution. We find two well-known types of cathode spots: “type 1” for less bright spots eroding the compound layer on the cathode surface and bright “type 2” spots on (clean) metallic surfaces. Cathode spots are characterized by a sequence of microexplosions that give the impression of a moving spot, which, in the presence of a magnetic field, is generally in the retrograde direction. However, the apparent displacement can also go in the opposite, the Amperian direction, especially when nitrogen is present. In oxygen, spot ignition often happens in approximately the same location repeatedly. For type 2 spots, we detected an apparent motion mainly in the retrograde direction with distinct jumps to new locations. Via the effects of spot appearance, we note the competing effects of cathode cleaning by spot-induced material removal (erosion) and compound formation in the presence of reactive gas. The streak images were analyzed by fast Fourier transformation, and we found that the arc fluctuations are stochastic without specific frequencies. The colored random noise (CRN) index tends to be reduced in the presence of a compound layer, indicating an enhanced spot ignition probability. A reduced CRN index implies reduced feedback (influence) of previously active spots, which is most apparent in the presence of elevated oxygen pressure.

N-Alkynylindoles were divergently cyclized for the synthesis of multi-fused N-heterocycles. An ortho-aryl palladium species was added to the -position of an ynamine to generate (Z)-6-alkylidene/benzylidene-6H-isoindolo[2,1-a]indoles, while Pt-catalyzed -addition via -activation gave 5-alkyl/arylindolo[2,1-a]isoquinolines. Double cyclizations using PdCl2 and oxidant afforded bright yellow benzo[7,8]indolizino[2,3,4,5-ija]quinolines, the synthesis of which was also demonstrated in a different synthetic route.

In most cases of ingested foreign bodies, endoscopy is the first treatment of choice. Moreover, emergency endoscopic removal is required for sharp and pointed foreign bodies such as animal or fish bones, food boluses, and button batteries due to the increased risks of perforation, obstruction, and bleeding. Here, we presented two cases that needed emergency endoscopic removal of foreign bodies without sufficient fasting time. Foreign bodies could not be visualized by endoscopy due to food residue; therefore, fluoroscopic imaging was utilized for endoscopic removal of foreign bodies in both cases.

The phase velocity of the wakefield of a laser wakefield accelerator can, theoretically, be manipulated by shaping the longitudinal plasma density profile, thus controlling the parameters of the generated electron beam. We present an experimental method where using a series of shaped longitudinal plasma density profiles we increased the mean electron peak energy more than 50%, from 175 ± 1 MeV to 262 ± 10 MeV and the maximum peak energy from 182 MeV to 363 MeV. The divergence follows closely the change of mean energy and decreases from 58.9 ± 0.45 mrad to 12.6 ± 1.2 mrad along the horizontal axis and from 35 ± 0.3 mrad to 8.3 ± 0.69 mrad along the vertical axis. Particle-in-cell simulations show that a ramp in a plasma density profile can affect the evolution of the wakefield, thus qualitatively confirming the experimental results. The presented method can increase the electron energy for a fixed laser power and at the same time offer an energy tunable source of electrons.

Nanoparticles in a laser-produced plasma can act as a sensitive control knob for inducing highly localized electron injection. The benefits of nanoparticles for laser-plasma electron accelerators have not been examined, though, due to complex effects on the plasma fluid and difficulties in getting nanoparticles into the plasma. Here the authors demonstrate nanoparticle-assisted laser wakefield acceleration by succeeding at incorporating nanoparticles into the plasma medium, obtaining prominent enhancement of beam quality by controlling the electron injection process. This work could promote applications of nanoscience to laser-plasma accelerators, and open a path to $a\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}o\phantom{\rule{0}{0ex}}s\phantom{\rule{0}{0ex}}c\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}c\phantom{\rule{0}{0ex}}e$.

Two outbreaks of gastroenteritis occurred in South Korea, affecting a middle school in the Jeollanam-do province in 2013 (Outbreak 1) and 10 schools in the Incheon province in 2014 (Outbreak 2). We investigated the outbreaks to identify the pathogen and mode of transmission.A retrospective cohort study was conducted in the Outbreak 1; and case-control studies were performed for the Outbreak 2. Samples from students, environments, and preserved food items were collected and pulsed-field gel electrophoresis (PFGE) was conducted to identify strains of pathogen.We identified 167 and 1022 students who met the case definition (≥3 loose stools in any 24-h period) in the Outbreaks 1 and 2, respectively. The consumption of cabbage kimchi and young radish kimchi were significantly associated with the illness. Adjusted odds ratios of kimchi were 2.62-11.74. In the Outbreak 1, cabbage kimchi was made and consumed in the school restaurant and in the Outbreak 2, young radish kimchi was supplied by food company X and distributed to all the 10 schools in the Incheon province. Enterotoxigenic Escherichia coli (ETEC) O6 was isolated from fecal samples in 375 cases (33.9%) and from kimchi samples. PFGE patterns of the outbreak strains isolated from cases and food were indistinguishable in each outbreak.The suspected food vehicle in these two consecutive outbreaks was kimchi contaminated with ETEC O6. We recommend continued monitoring and stricter sanitation requirements for the food supply process in Korea, especially in relation to kimchi.

IgG4-related sclerosing cholangitis (IgG4-SC) represents a rare but clinically challenging differential diagnosis in patients with biliary strictures which can be mistaken for cholangiocarcinoma. We present a case of a 73-year-old male presented with abdominal discomfort and weight loss. Biliary images showed long-segment luminal narrowing of extrahepatic bile duct associated with prominent enhanced wall thickening, but luminal patency was preserved. Pancreatic images revealed segmental irregular narrowing of main pancreatic duct without upstream duct dilatation. His liver function tests and CA19-9 level were normal. Putting all findings together, IgG4-SC associated with autoimmune pancreatitis was strongly suspected. However, endobiliary biopsy of extrahepatic bile duct revealed adenocarcinoma which was not resectable due to celiac axis involvement. Because there is an overlap in biliary imaging findings between IgG4-SC and cholangiocarcinoma, biopsy is essential for adequate differential diagnosis. We present a case of cholangiocarcinoma masquerading as IgG4-SC based on clinical and imaging findings.

In the electrochemical detection method for pesticides that measures their inhibitory effects on acetylcholinesterases (AChEs), the direct electrooxidation of the enzyme product (thiocholine, SCh) is slow at conventional electrodes. To overcome this limitation, an electron mediator is required to lower the applied potential and facilitate the transfer of electrons between the enzyme product and electrode. In this study, [Ru(NH3)5py]3+ is introduced as an electron mediator in inhibition-based pesticide detection. To obtain a better signal-to-background ratio, [Ru(NH3)5py]3+, which undergoes a fast outer-sphere reaction, is combined with low-electrocatalytic indium-tin-oxide (ITO) electrodes at which many interfering species undergo slow redox reactions. AChE is immobilized onto an avidin-modified ITO electrode via the direct adsorption of avidin onto ITO followed by the biospecific binding of biotinylated AChE to the avidin. SCh is generated from acetylthiocholine by AChE. Subsequently, SCh converts [Ru(NH3)5py]3+ to [Ru(NH3)5py]2+, which is then oxidized at the ITO electrode. This procedure allows the sensitive detection of carbaryl at a low applied potential of 0.15 V vs Ag/AgCl. The calculated detection limit for carbaryl is approximately 0.3 pM. This simple and sensitive pesticide sensor is thus very promising and should be extendable to the onsite environmental monitoring of other pesticides.

A base-controlled Cu-catalyzed tandem cyclization/alkynylation of propargylic amines provides rapid access to functionalized indolizine derivatives under mild reaction conditions. The reaction first proceeded via a 5-endo-dig aminocupration, followed by a coupling between the copper-bound intermediate and alkynyl bromide, to afford the products in good to excellent yields. The successful tandem reaction is attributed to the unique property of the bases, DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) and MTBD (7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene used).

We compared 47 enterohemorrhagic Escherichia coli (EHEC) O157 isolates with 184 EHEC non-O157 isolates from Korean patients with diarrhea. In the O157 group, the strains harboring both Shiga toxin genes (stx1 and stx2) were detected with highest frequency, whereas the strains harboring only stx1 gene were most frequently detected in the non-O157 group. Eight virulence genes (eaeA, hlyA, ehx, iha, efa1, tir, toxB, and espA) were found to show a higher frequency of occurrence in the O157 group than in the non-O157 group. In addition, the symptom of bloody diarrhea was exhibited at a higher rate in the O157 group (51.1%) than in the non-O157 group (16.8%). Our findings demonstrate that EHEC O157 strains are more frequently implicated in cases of bloody diarrhea in the Korean population than EHEC non-O157 strains.

The properties of secondary particles for sputtering silicon with primary low-energy oxygen ions were investigated with dependence on the primary ion energy Eion and geometric parameters (ion incidence angle, polar emission angle, and scattering angle). The mass and energy distributions of the secondary particles were measured by energy-selective mass spectrometry. The experimental results were compared with simulations using the Monte Carlo code sdtrimsp and with calculations based on a simple elastic binary collision model. The main secondary ion species were found to be O+, O2+, Si+, and SiO+. Their energy distribution functions depend on the primary ion energy Eion and the scattering angle γ. For O+, Si+, and SiO+ ions, a decreasing scattering angle γ or an increasing primary ion energy Eion leads to a pronounced feature in the high-energy part of the distributions. The energy distributions of the secondary O2+ ions show hardly any changes with regard to the primary ion energy or the scattering angle γ. In the case of the O+ ions, the energy distribution appears to reflect several direct scattering channels, which could be associated with the primary ion energy Eion, and half of the ion energy Eion/2. The present experimental results are compared with previous investigations for the sputtering of Si with the noble gas ions, such as Ne+, Ar+, and Xe+.

Comamonas testosteroni and Acinetobacter guillouiae are gram-negative bacilli of low virulence that are widely distributed in nature and normal flora. Despite their common occurrence in environments, they rarely cause infectious disease. We experienced a case of septic shock by C. testosterone and A. guillouiae, and isolated them by 16S ribosomal RNA sequencing method from the blood cultures of a previous healthy female during postoperative supportive care. This is the first case of septic shock required ventilator care and continuous renal replacement therapy due to these organisms in Korea.

In June 2013, a diarrheal outbreak occurred among high school students in Incheon, South Korea. We investigated the outbreak to identify the pathogen and mode of transmission. A case-control study using a self-administered questionnaire was conducted by local authorities and the Korean Centers for Disease Control and Prevention. Bacterial cultures of stool samples, environmental samples, and samples of preserved food items were prepared. PCR, serotyping, and pulsed-field gel electrophoresis (PFGE) were used to identify and characterize the outbreak-related pathogen. We identified 54 cases of gastroenteritis, with symptoms including diarrhea, abdominal pain, and nausea. None of the food items served in the high school cafeteria were significantly associated with illness, although the odds ratio for kippered trotters mixed with vegetables was relatively high (odds ratio: 2.92, 95% confidence interval: 0.62-13.69). Enteroaggregative Escherichia coli (EAEC) was isolated from this item and the stool samples from 22 symptomatic students and 4 asymptomatic food handlers. The PFGE patterns of EAEC isolated from these sources were indistinguishable. This outbreak was caused by EAEC, and kippered trotters mixed with vegetables, perhaps contaminated by asymptomatic food handlers, were linked to the outbreak. This case-control study highlights the importance of safe food preparation.

We investigated an outbreak of enterotoxigenic Escherichia coli (ETEC) O159:H20 associated with the consumption of a tossed-noodle dish in a high school in 2016. Thirty-three ETEC strains isolated from clinical and food samples were genetically indistinguishable. The outbreak strains were resistant to third-generation cephalosporins and harbored a bla CTX-M-15 gene on a 97-kb self-transferable IncK plasmid. This is the first outbreak caused by CTX-M-15-producing ETEC strains.

A copper-catalyzed regiocontrolled three-component reaction afforded diversified 4-aminoquinolines using nitriles, diaryliodoniums, and ynamides. The C7-substituted regioisomers were formed regioselectively when meta-substituted phenyliodonium salts were used. [1,3] N-to-C rearrangement of the products to quinolin-4-ylmethanesulfonamides and simultaneous deprotection of benzyl and sulfonamide group were newly developed. Finally, antimalarial CK-2-68 was successfully prepared.

Intestinal inflammation and mucosal damage in Crohn’s disease (CD) are believed to progress even during clinical remission. We investigated the long-term prognosis of CD patients in clinical remission according to serum C-reactive protein (CRP) levels. This study included 339 CD patients in clinical remission (Crohn’s disease activity index < 150) for more than 6 months between January 2008 and December 2010. Clinical outcomes were compared between patients with normal and elevated CRP levels during clinical remission. During clinical remission, 150 patients had normal CRP consistently and 189 had elevated CRP at least once. During follow-up (median, 7.9 years [interquartile range, 6.8–8.0]), the Kaplan–Meier analysis with the log-rank test showed that normal CRP group had a longer CD-related hospitalization-free survival (P = 0.007) and a longer CD-related intestinal resection-free survival (P = 0.046) than elevated CRP group. In multivariate analysis, elevated CRP was significantly and independently associated with an increased risk of subsequent CD-related hospitalization (adjusted hazard ratio [aHR] 1.787, 95% confidence interval [CI]: 1.245–2.565, P = 0.002) and of subsequent CD-related intestinal resection (aHR 1.726, 95% CI: 1.003–2.969, P = 0.049). The most common reason for CD-related hospitalization was penetrating complications (35.6%). Even when CD patients are in clinical remission, elevated CRP is significantly associated with subsequent CD-related hospitalization and CD-related intestinal resection during follow-up. CD patients in clinical remission but elevated CRP should receive more careful attention and timely interventions to improve long-term outcomes.

Although early treatment of Crohn's disease (CD) patients with anti-tumor necrosis factor (TNF) agents or immunomodulators (IMs) may improve long-term outcomes, especially those with poor prognostic factors, their effectiveness in Asians remains unclear. In this study, Korean patients with CD naive to both intestinal surgery and intestinal complications, and with at least two risk factors for progression (diagnosis at age

Background: In May 2013, an outbreak of gastroenteritis occurred in a high school in Incheon, South Korea. We investigated the outbreak in order to identify the pathogen and mode of transmission.A case-control study was performed using standardized questionnaires with a case definition of illness with diarrhea. Stool samples, environmental samples, and samples from preserved food items were collected to test pathogens. Pulsed-field gel electrophoresis (PFGE) was performed on the outbreak-related Escherichia coli strains.Thirty-three people (attack rate: 2.5%) met the case definition, and the pattern of the epidemic curve suggested a point-source outbreak. The common symptoms of cases were diarrhea (100.0%), abdominal pain (75.8%), chills (45.5%), and nausea (39.4%). Cases were found to be 8.26 times more likely to have eaten spicy fish soup with cod (95% confidence interval: 1.05-65.01). Consumption of egg soup with spring onions or braised eggs with razor clam flesh was significantly associated with illness. Atypical enteropathogenic E. coli O157:H45 was isolated from samples of 9 cases (27.3%) and tuna bibimbap. PFGE patterns of all tested isolates of O157 serotype were indistinguishable.This outbreak was caused by atypical enteropathogenic E. coli O157:H45 and the food vehicle was suspected to be tuna bibimbap. The statistical analysis was not in concordance with the microbiologic tests, probably owing to low pathogenicity of atypical enteropathogenic E. coli O157. This is the first report of an outbreak caused by atypical enteropathogenic E. coli O157.

Certain Escherichia coli (E. coli) strains have the ability to cause diarrheal disease. Five types of diarrheagenic E. coli have been identified, including EHEC, ETEC, EPEC, EAEC, and EIEC. To detect these five diarrheagenic types rapidly, we developed a one-step multiplex PCR (MPPCR) assay using nine primer pairs to amplify nine virulence genes specific to the different virotypes, with each group being represented (i.e., stx1 and stx2 for EHEC, lt, sth, and stp for ETEC, eaeA and bfpA for EPEC, aggR for EAEC, and ipaH for EIEC). The PCR primers were constructed using MultAlin. The sensitivity and specificity of the constructed multiplex PCR primers were measured using DNA isolated from diarrheagenic E. coli strains representing each group. The limits of detection were as follows: 5 × 10(1) CFU/ml for EHEC, 5 × 10(3) CFU/ml for ETEC expressing lt and sth, 5 × 10(4) CFU/ml for ETEC expressing stp, 5 × 102 CFU/ml for EPEC, 5 × 10(4) CFU/ml for EAEC, and 5 × 10(2) CFU/ml for EIEC. To confirm the specificity, C. jejuni, C. perfringens, S. Typhimurium, V. parahaemolyticus, L. monocytogenes, Y. enterocolitica, B. cereus, and S. aureus were used as negative controls, and no amplification was obtained for these. Moreover, this kit was validated using 100 fecal samples from patients with diarrhea and 150 diarrheagenic E. coli strains isolated in Korea. In conclusion, the multiplex PCR assay developed in this study is very useful for the rapid and specific detection of five diarrheagenic E. coli types. This single-step assay will be useful as a rapid and economical method, as it reduces the cost and time required for the identification of diarrheagenic E. coli.

본 연구는 문제풀이 중심으로 운영되는 고등학교 생명과학 수업에서 교육매체의 일종인 교실응답시스템(CRS)의 활용 가능성을 알아보고자 하였다. 교수·학습 전략으로 CRS 활용반(34명)은 학생들이 CRS 단말기로 응답한 결과를 교사가 즉시 파악하고 개인별 응답 이유를 질문한 후 피드백을 하였다. 비교반(34명)에서는 CRS를 사용하지 않았으며 학생들에게 일괄적인 피드백을 하였다. 연구 결과, CRS 활용이 학생들로 하여금 수업 활동에 흥미와 집중력을 높여주는 것으로 인식되었다. 그러나 학업 성취도의 향상에 있어서 CRS 활용반과 비교반 사이에 유의한 차이는 없었다. 다만 성적 수준에 따라 그룹을 나누었을 때, 중위그룹에서는 CRS 활용반과 비교반 사이에 학업 성취도의 향상에 유의한 차이를 보였다. 진단평가 및 형성평가에서 CRS 활용의 효과를 높이기 위해서는 다양한 수준의 문제들을 사전에 개발하고, 학생들의 응답 이유를 정확히 파악하여 더욱 많은 학생들에게 개인별 맞춤형 피드백을 할 수 있는 교수 전략의 개발이 필요함을 제안한다.

Quorum sensing and the stringent response are well-known regulation systems for the expression of virulence genes in enterohemorrhagic Escherichia coli (EHEC). However, how these two systems interact is not well known. E. coli strains with mutations in two regulation systems, ΔluxS (ECM101) and ΔluxSΔrelAΔspoT (ECM201), and the ΔluxS complement strain to ECM201 (ECM202) were created from EHEC O157:H7 EDL933 to investigate how the regulatory systems interact. The phenotypic changes of the mutant strains were characterized and compared with the wild type. The mutant strains exhibited no obvious growth defects, although acid resistance and cellular cytotoxicity were decreased significantly in all the mutant strains. Phenotypic characterization revealed that mutations in the stringent response system (ECM201 and ECM202) influenced the metabolic (defective utilization of arabinose and L-sorbose) and enzymatic activities (decreased trypsin activity, and increased α-glucosidase activity). In contrast, the quorum sensing system mutant (ECM101) did not display these phenotypes. The motility of the quorum sensing system mutant (ECM101) was unchanged, but mutation in the stringent response system influenced the motility. Our results suggest that quorum sensing interacts with the stringent response regulation system.

We compared 47 enterohemorrhagic Escherichia coli (EHEC) O157 isolates with 184 EHEC non-O157 isolates from Korean patients with diarrhea. In the O157 group, the strains harboring both Shiga toxin genes (stx1 and stx2) were detected with highest frequency, whereas the strains harboring only stx1 gene were most frequently detected in the non-O157 group. Eight virulence genes (eaeA, hlyA, ehx, iha, efa1, tir, toxB, and espA) were found to show a higher frequency of occurrence in the O157 group than in the non-O157 group. In addition, the symptom of bloody diarrhea was exhibited at a higher rate in the O157 group (51.1%) than in the non-O157 group (16.8%). Our findings demonstrate that EHEC O157 strains are more frequently implicated in cases of bloody diarrhea in the Korean population than EHEC non-O157 strains.