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Background Nasopharyngeal (NP) colonization with Streptococcus pneumoniae and non-typeable Haemophilus influenzae (NTHi) is common in children, and may evolve as the source of invasive infections. In Korea, the pneumococcal conjugate vaccines (PCVs) were introduced >10 years ago, enabling the authors to study the effect of the vaccine in preventing carriage. Methods NP swabs were taken and a household survey was conducted at daycare centres located in different regions of Korea in 2014 and 2019. Pneumococcal serotypes were identified using the Quellung method and sequencing. NTHi were identified based on pilA and bexA genes. Results In total, 1460 NP swabs were obtained with pneumococcal carriage rates of 36.4–42.1% and NTHi carriage rates of 36.5–26.7%. Among children carrying pneumococci, a significant increase was seen in serotype 23A between 2014 and 2019 (from 12.6% to 22.0%; P=0.005). Children who had received PCV were at lower risk of vaccine-type carriage (2.9% vs 0.8%; P=0.005). Conclusions Between 2014 and 2019, the proportion of children carrying serotype 23A increased significantly, while the carriage rate of NTHi decreased. Continuous surveillance is needed to assess the long-term effects of the PCVs on carriage dynamics of pneumococcus and NTHi.

This article reports five invasive Group B streptococcal (GBS) infections that occurred in a neonatal intensive care unit for about 3 months. This outbreak might have been associated with a prolonged GBS colonized infant and adjacent environmental contaminations. Infection control interventions prevented the additional spread of GBS infections. Keywords: Neonatal intensive care unit, Outbreak, Streptococcus agalactiae

Compared with wet processes, dry functionalization using plasma is fast, scalable, solvent-free, and thus presents a promising approach for grafting functional groups to powdery nanomaterials. Previous approaches, however, had difficulties in maintaining an intimate sample-plasma contact and achieving uniform functionalization. Here, we demonstrate a plasma reactor equipped with a porous filter electrode that increases both homogeneity and degree of functionalization by capturing and circulating powdery carbon nanotubes (CNTs) via vacuum and gas blowing. Spectroscopic measurements verify that treatment with O2/air plasma generates oxygen-containing groups on the surface of CNTs, with the degree of functionalization readily controlled by varying the circulation number. Gas sensors fabricated using the plasma-treated CNTs confirm alteration of molecular adsorption on the surface of CNTs. A sequential treatment with NH3 plasma following the oxidation pre-treatment results in the functionalization with nitrogen species of up to 3.2 wt%. Our approach requiring no organic solvents not only is cost-effective and environmentally friendly, but also serves as a versatile tool that applies to other powdery micro or nanoscale materials for controlled modification of their surfaces.

In this study, ten fluorescent dyes were prepared based on three different kinds of central moiety, such as triphenylamine, diphenylsulfone or triphenyltriazine, which was coupled to either carbazole or naphthalimidinyl group via an acetylene linkage group. N-n-Butyl-carbazole, N-phenyl-carbazole or N-n-butyl-naphthalimide was coupled to the individual central moiety of triphenylamine, diphenyl sulfone, 2,4,6-triphenyl-1,3,5-trazine or diphenylamine using a Sonogashira coupling reaction in the final step. All dyes were confirmed their chemical structure by 1H NMR, GC-Mass and elemental analyses. The absorption properties and thermal stabilities of the fluorescent dyes were examined. Density Functional Theory (DFT) and Time-Dependent DFT calculations were carried out, in addition to geometry simulation, by using the Gaussian 09 program. In terms of fluorescence properties in this series, two dyes based on diphenyl sulfonyl and three dyes based on triphenylamine substituted by 1–3 of N-n-butyl-carbazole exhibited a blue emission, whereas three dyes based on triphenylamine substituted by 1–3 of N-n-butyl-naphthalimide were observed by a red emitter which can be attributable to both effects the bathochromic shifts in absorption maxima and larger Stokes shifts. In case of corresponding 2,4,6-triphenyl-1,3,5-trazine central moiety coupled to a carbazole ring, a green fluorescence was emitted. Results revealed that the fluorescence of the dyes is affected by the electron-donating strength of the acetylene linkages involved in the π-conjugation systems of the dyes.

We analyzed 155 clinical group A Streptococcus (GAS) isolates from children at the Seoul National University Children's Hospital between 1991 and 2012 and the Seoul National University Bundang Hospital between 2006 and 2012. The erythromycin resistance rate was 10.3% (16/155), and all isolates during the recent 3 years were susceptible to erythromycin. Among isolates, emm1 (19.4%), emm12 (18.7%), and emm4 (18.1%) were the most prevalent emm types. According to clinical disease, emm1 was most common in invasive GAS infections (47.4%), and emm4, in scarlet fever (48.8%). From 2010 to 2012, an increase in invasive GAS infections and scarlet fever that correlated with an increase in emm1 and emm4 types was observed. The speC detection rate was higher in patients with scarlet fever than in those with other GAS infections (P=0.017). Recently, invasive GAS infections and scarlet fever were associated with an increase in emm1 and emm4, respectively.

The contrast ratio is an important color property of liquid crystal displays. Color properties are classified as colors' purity, contrast ratio, and brightness; these mainly depend on pigment properties. The contrast ratio in particular can be improved by minimizing the light scattering of pigment particles, which is directly related to their degree of dispersion. Therefore, synergists are usually employed to increase the contrast ratio by augmenting the dispersion efficiency. In this study, tricyanopyrrolidone derivatives as blue color synergists were synthesized and examined for their performance to improve the contrast ratio of liquid crystal displays. The results of this study prove that tricyanopyrrolidone derivatives as synergists for blue pigment effectively improve the contrast ratio.

The effect of neutralization with Et 3 Al on morphologies in a sulfonated pentablock copolymer solution and cast membrane was investigated using small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). The sulfonated pentablock copolymer in a non-polar solvent mixture (cyclohexane/heptane) persists as spherical micelles after neutralization where the micelle core of sulfonated polystyrene (SS) incorporates Al (3+) ions and the corona is solvated hydrogenated isoprene (HI) and t -butylstyrene ( t BS). Membranes cast from this micellar solution exhibit a bicontinuous microphase separated morphology with interconnected SS microdomains. The aluminum-neutralized membrane with a continuous transport channel shows excellent water vapor transport rate (WVTR) (22 kg/(m 2 day)), which is comparable to the WVTR of membranes in the sulfonic acid form. The strong interaction between Al(3+) ions and the sulfonic acid group in the aluminum-neutralized membrane results in significantly lower water uptake (∼30 wt%) that provides much-improved mechanical stability in the wet state.

ZnO was used to decrease the sintering temperature of 1.5 mol% MnO2-added (Na0.5K0.5)NbO3(MNKN) ceramics. When a small amount of ZnO (≥2.0 mol%) was added, a dense microstructure was observed for specimens sintered at 960 °C, with high relative density of 96.0% of the theoretical density. The liquid phase, which was considered to be an Nb2O5–MnO–ZnO related phase, was formed in the ZnO-added MNKN ceramics and abnormal grain growth occurred in its presence. Therefore, although a very small amount of ZnO might enter the matrix of the MNKN, most of the ZnO was used to form the liquid phase and assisted the densification of the specimens, indicating that the hardening effect of Zn2+ was insignificant. The 2.0 mol% ZnO-added MNKN (ZMNKN) ceramics sintered at 960 °C exhibited the high piezoelectric properties of kp = 37%, e 3 T / e 0 = 297 , d33 = 120 pC/N, and Qm = 200. In addition, the reaction between the Ag electrode and the ZMNKN ceramic sintered at 960 °C was negligible.

Nitroxide-mediated polymerization enabled the synthesis of cationic, imidazolium-containing triblock copolymers as a membrane for an electromechanical transducer. Nitroxide-mediated polymerization afforded poly(styrene- b -[1-ethyl-3-(4-vinylbenzyl)imidazolium bis(trifluoromethane sulfonyl)imide)]- b -styrene) in a controlled fashion as confirmed using aqueous size exclusion chromatography and 1 H NMR spectroscopy. Dynamic mechanical analysis revealed a modulus of approximately 100 MPa for the triblock copolymer at 23 °C, which was suitable for fabrication of an electromechanical actuator. Evaluation of electromechanical actuators revealed device curvatures over twice the curvatures for Nafion ® in both the presence and absence of a conductive network composite. Addition of the ionic liquid (IL) 1-ethyl-3-methylimidazolium trifluoromethane sulfonate selectively reduced the glass transition temperature ( T g ) of the central block and increased overall ionic conductivity. Normalizing temperature with the central block T g caused the ionic conductivity for the IL-incorporated polymers to collapse onto a single curve, which was an order of magnitude higher than the block copolymer in the absence of added IL.

Multilayered ceramics (MLCs) laminated with 20 layers of CuO-added (Na0.5K0.5)NbO3 (CNKN) tape were well sintered at 960 °C with an average grain size of 5.0 μm. They exhibited good piezoelectric properties of e 33 T / e 0 = 709 , d33 = 114 pC/N, kp = 0.34 and Qm = 793. The 80Ag/20Pd electrodes were well formed on the CNKN MLCs when they were co-fired at 960 °C for 2 h. A piezoelectric speaker fabricated using 6-layer CNKN MLCs exhibited an average sound pressure level (SPL) of 75 dB in the range between 300 and 20,000 Hz with a maximum SPL of 90 dB. This value is comparable with that of a loud stereo radio, indicating that the CNKN MLC is a good candidate material for piezoelectric speakers.

The morphology of a series of poly( t -butylstyrene- b -hydrogenated isoprene- b -sulfonated styrene- b -hydrogenated isoprene- b - t -butylstyrene) (tBS-HI-SS-HI-tBS) pentablock copolymer membranes with a range of ion exchange capacity (IEC) was investigated with small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). Comparing the sizes of the micelle cores (2 R ), obtained from SAXS of the micellar solutions in cyclohexane/heptane, to the interparticle distances ( d ), obtained from SAXS and TEM imaging of the membranes, reveals that membranes with a low SS volume fraction (0.4, 0.7 and 1.0 mequiv./g IECs) show discrete SS microdomains within a HI-tBS matrix, while high SS volume fraction membranes (1.5 and 2.0 mequiv./g IECs) exhibit a bicontinuous microphase separated morphology without long-range order. As ion exchange capacity increases from 1.0 to 1.5 mequiv./g, the morphological transition from discrete SS microdomains to interconnected SS microdomains results in a significant increase in water vapor transport rate. When exposed to liquid water, the extent of water uptake and the increase in primary spacing of the membranes are greater at higher sulfonation levels suggesting that absorbed water plasticizes the hydrophilic SS microdomains.

BaTiO 3 (BT) nanopowders were synthesized using the alkoxide–hydroxide route. Formation of BT nanopowders commenced at 60 °C and their amount increased with increasing temperature. However, a TiO 2 second phase was always developed at temperatures higher than 100 °C due to the insufficient amount of H 2 O caused by its evaporation. Therefore, a two-step process is presented herein for the synthesis of homogeneous, highly tetragonal BT nanopowders. The cubic BT nanopowders were synthesized at 100 °C and subsequently heated to high temperatures (>200 °C) to increase their tetragonality. Homogeneous BT nanopowders with an average size of 94.8 nm and a high c / a ratio of 1.0081 were obtained for the specimens synthesized at 260 °C for 60 h after the formation of the cubic BT nanopowders at 100 °C for 20 h.

Eight red perylene dyes were synthesized to improve the optical performance of LCD color filters. Among them, dyes with bulky functional substituents at the bay and terminal positions were highly soluble in cyclohexanone, the industrial solvent currently used in the pigment dispersion method. The spectral properties and thermal stability of the dye-based color filters with these dyes were examined by comparing them with pigment-based ones. The prepared color filters exhibited superior spectral properties due to the smaller particle size of the dyes, which led to less light scattering. However, their thermal stability varied with the dye structures, and only the dyes mono-substituted at the bay position had sufficient thermal stability.

[(Na 0.5 K 0.5 ) 1− x Li x ](Nb 0.96 Sb 0.04 )O 3 [NKLNS100 x ] ceramics with 0.0 ≤ x ≤ 0.1 were sintered at 1040 °C for 2 h and the specimens with x ≥ 0.05 had a dense microstructure due to liquid phase sintering. The specimen with x = 0.05 had both orthorhombic and tetragonal phases, and showed good piezoelectric properties of k p = 0.43, d 33 = 243 pC/N and ɛ 33 T / ɛ 0 = 990. The [(Na 0.5 K 0.5 ) 0.95 Li 0.05 ](Nb 0.96 Sb 0.04 )O 3 [NKLNS5] ceramics sintered at 960 °C also showed a high density by the addition of CuO, due to the production of the CuO and Na 2 O-related liquid phase. The Cu 2+ ions were considered to replace Nb 5+ ions and act as a hardener, which increased the Q m value of the NKLNS5 ceramics. High piezoelectric properties of k p = 0.37, Q m = 560, ɛ 33 T / ɛ 0 = 600 and d 33 = 170 pC/N were obtained from the specimen containing 1.5 mol% of CuO sintered at 960 °C for 2 h.

A series of structurally isomeric water-soluble azo naphthalene dyes were synthesized, and their thermal properties were examined by thermogravimetric analysis and differential scanning calorimetry. Dye-based color filters were also fabricated using the synthesized dyes. Transmittance (98.9%) at 650 nm and a wide color gamut (62.8%) were achieved using one of the color filters. All the prepared dyes had a degradation temperature above 280 °C, which varied with the dye structure. The degradation temperatures of the dyes were presumed to be related to the intra- and inter-molecular interactions of the structural isomers. From quantum mechanics calculations, their intra-molecular interactions were similar. However, the degradation temperatures generally increased in proportion to their density. According to the molecular mechanics calculations, the different structures induced changes in electrostatic attraction, steric hindrance and linearity of the dyes, which in turn caused changes in their molecular packing geometry, density and degradation temperature.

The sintering temperature of 0.75Pb(Zr 0.47 Ti 0.53 )O 3 –0.25Pb(Zn 1/3 Nb 2/3 )O 3 ceramics containing 1.5 mol% MnO 2 was decreased from 930 to 850 °C with the addition of CuO. The CuO reacted with the PbO and formed a liquid phase during the sintering, which assisted the densification of the specimens. Most of the Cu 2+ ions existed in the CuO second phase, thereby preventing any possible hardening effect from the Cu 2+ ions. Variations of the k p , Q m , ɛ 3 T / ɛ 0 and d 33 values with CuO were similar to that of the relative density. The specimen containing 0.5 mol% CuO sintered at 850 °C showed the good piezoelectric properties of k p = 0.5, Q m = 1000, ɛ 3 T / ɛ 0 = 1750 and d 33 = 300 pC/N.

Three thermally-stable red dyes of azo, quinacridone and perylene derivatives were synthesized and dye-based color filters were manufactured for use in liquid crystal displays. The aggregation behavior of the dyes and their spectral properties in film state were investigated using field emission scanning electron microscopy and concentration-dependent spectroscopy. Aggregate size was related to the geometry of the three dye types rather than their size, with average aggregate sizes ranging from 35 nm (azo), 80 nm (quinacridone) to 25 nm (perylene). Aggregation behavior affected the spectral property of the red color filter, resulting in weaker and broader transmittance spectrum with higher aggregation.

The effect of morphology on ion transport in ionic liquid-based solid-state films was investigated. In this study, mixtures of a block copolymer, poly(styrene-b-methyl methacrylate) (SbMMA), and an ionic liquid (IL), 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl)imide (EMIm-TFSI), were prepared as clear solid-state films at various IL compositions (0–50 wt%) by solution casting from a volatile co-solvent. The IL was preferentially miscible with the MMA block as evidenced by visual inspection and differential scanning calorimetry. Both equilibrium and non-equilibrium morphologies were identified with X-ray scattering and transmission electron microscopy and the morphology varied with MMA/IL volume fraction. The morphology and microdomain orientation had a significant impact on ionic conductivity. Higher through-plane conductivities were observed in morphologies with a three-dimensionally continuous conducting path (e.g., non-conducting S cylinders) compared to morphologies with a non-continuous conducting path (e.g., lamellae). When the lamellae were oriented in the plane, the through-plane conductivity was significantly lower than the in-plane conductivity, while the conductivity was direction-independent when the morphologies have a continuous conductive path. Also, a significant increase in conductivity was observed with increasing IL content at the glass transition of the conductive (MMA/IL) microdomain. Finally, significantly higher ionic conductivities can be achieved in a block copolymer/IL solid-state film compared to a homopolymer/IL film at the same IL content (wt%), because the non-conductive microdomain excludes IL, which produces a higher local IL concentration in the conductive phase.

Bi 6 Ti 5 TeO 22 (BTT) thin films were grown on a Pt/Ti/SiO 2 /Si(1 0 0) substrate under various conditions and the valence state of the Te ion was investigated. For the BTT films grown at 300 °C, most of the Te ions existed as Te 4+ ions. However, for the 10 mol% Mn-added BTT films grown at 300 °C, Te 6+ ions were found even in the film grown under low oxygen partial pressure (OPP) and their number increased with increasing OPP. This increase was attributed to the presence of Mn 2+ ions, which assisted the transition of Te 4+ ions to Te 6+ ions in order to maintain the charge balance of the Ti 4+ sites. Furthermore, in the films grown at 300 °C under a high OPP of 80.0 Pa and subsequently annealed at 600 °C under a high oxygen pressure of 101 kPa, most of the Te ions existed as Te 6+ ions. However, for the film grown at 300 °C under low OPP, even though the film was annealed under a high oxygen pressure of 101 kPa, only a few of Te 6+ ions were formed, whereas most of Te ions remained as the Te 4+ ions.

B2O3 (25.0 mol%) was added to Zn2−xSiO4−x ceramics (0.0 ≤ x ≤ 0.5) to decrease the sintering temperature. Specimens with 0.0 ≤ x ≤ 0.3 sintered at 900 °C were well sintered with a high density due to the formation of a B2O3 or B2O3–SiO2 liquid phase. The Q × f value of the Zn2SiO4 ceramic was relatively low, 32,000 GHz, most likely due to the presence of a ZnO second phase. A maximum Q × f value of 70,000 GHz was obtained for the specimens with x = 0.2–0.3, and their ɛr and τf values were approximately 6.0 and −21.9 ppm/°C, respectively. Ag metal did not interact with the 25.0 mol% B2O3-added Zn1.8SiO3.8 ceramic, indicating that Zn2−xSiO4−x ceramics containing B2O3 are a good candidate materials for low temperature co-fired ceramic devices.

A series of temporarily solubilised azo disperse dyes containing β-sulphatoethylsulphonyl group in their structures were synthesised for dispersant-free dyeing of polyester. Diazo components having nitro or bromo group were prepared and coupled with corresponding coupling components to give 4-diethylamino-4′-(2-sulphatoethylsulphonyl)azobenzene dyes. The absorption maxima of the dyes were dependent upon the substituents in the diazo and coupling components and varied from 464 to 528 in DMF. Polyester fabric was successfully dyed with the synthesised dyes without using any dispersing agent. The dyes showed good build-up, leveling and fastness properties on polyester.

A series of thienylazo and thiazolylazo disperse dyes has been prepared from their corresponding coupling components, 2-aminothiophenes and 2-aminothiazole. Depending on the various substituents present in the diazo component, absorption maxima varied from 437 to 534 nm in toluene. The spectroscopic properties of the azo dyes were examined with respect to the effects of 3- and 4-substituents present in the coupling component. Thus, the appropriate Hammett substituent constants could be related to the observed bathochromic shifts in the order CONH2<

A series of yellow to greenish-blue aziridinyl azo dyes and their azo precursors containing a thienyl coupling moiety has been prepared from 2-aminothiophenes. The 2-aminothiophenes were readily obtained by using the Gewald reaction. It was found that cyclisation of the precursor dyes to the corresponding aziridinoazo dyes brought about bathochromic shifts in absorption maxima. Further spectral comparisons with N-phenylazo dyes derived from other terminal cyclic groups, such as four-, five-, six-, seven- and eight-membered rings, showed that the N-thienylaziridinoazo dyes are relatively bathochromic. From the viewpoint of solvatochromism, a clear contrast existed between λmax values in different solvents; thus, a positive solvatochromism was observed in aprotic solvents, whereas a hypsochromic shift was brought about in polar protic solvents. PPP–MO calculations provided reliable predictions of absorption maxima for the various aziridinyl azo dyes and their precursor dyes.

A series of yellow to greenish-blue aziridinyl azo dyes and their azo precursors containing a thienyl coupling moiety has been applied to conventional polyester fibre as well as microdenier polyester by high temperature exhaust dyeing. Heat transferability of these dyes onto polyester fibre has also been examined, using conventional heat-transfer printing techniques. The relevant dyeing characteristics, heat transferability, build-up, dyeability on microfibre polyester, washfastness and lightfastness are given. These aziridinyl dyes are reactive to polyester fibres under HT dyeing conditions. Fabrics dyed with aziridinyl dyes are more resistant to solvent extraction than those dyed with conventional dyes. Residual liquors showed only a pale colour when fabric dyed with aziridinyl dyes was dissolved and then precipitated, whereas a coloured polyester precipitate was obtained.