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Background Varicella-zoster virus (VZV) infection is known to occur in 13-55% of patients within the first year after hematopoietic stem cell transplant (HSCT). The dynamics of recovery of VZV-specific T cell- mediated immunity (CMI) and its role for prevention and control of VZV reactivation are rarely reported in pediatric allogenic HSCT recipients. Methods From April 2019 to February 2020, subjects aged younger than 19 years who underwent allogenic HSCT with at least 1 year of follow up at Asan Medical Center Children`s Hospital were prospectively enrolled. All of them underwent VZV-specific enzyme-linked immune absorbent spot (ELISPOT) assays just before HSCT and then at 1, 3 months following HSCT. Extension study, which measures VZV-specific CMI before and after VZV vaccination at 24 months post-HSCT, is currently underway. Results A total of 32 HSCT recipients with a median age of 11years were enrolled. 37.5% underwent haploidentical HSCT and VZV R+ were in 78.1%. Antiviral prophylaxis was applied to all HSCT recipients, of which 65.6% were applied up to 365 days after HSCT. During this study period, only 1 patient (3.1%) experienced herpes zoster at 23 months following HSCT, whose VZV-specific ELISPOT assay showed 0, 1, and 0 spot-forming cells (SFC)/2.0x105 cells before HSCT, 1 and 3 months following HSCT, respectively. The presence of VZV-specific CMI ≥ 1 SFC/ 2.0 × 105 cells was observed in 62.5 % before HSCT, 65.6 % at 1 month, 59.4 % at 3 months, and 70% at 24 months after HSCT, respectively. However, only 18.8 % ,12.5 % and 21.9 % recovered VZV-specific CMI with ≥ 5 SFC/ 2.0 × 105 cells at 1, 3 and 24 months following HSCT. Meanwhile, all the 4 recipients who got the 1st VZV vaccination at 24 months following HSCT showed recovery of VZV-specific CMI with ≥ 5 SFC/ 2.0 × 105 cell. Recovery of VZV-specific CMI after HSCT was not associated with VZV serostatus, chickenpox history, type of HSCT, conditioning regimens, and GVHD. Conclusion Only a few pediatric allogenic HSCT recipients recovered VZV-specific CMI with ≥ 5 SFC/ 2.0 × 105 cell up to 2 years following HSCT. In addition, the association between VZV-specific CMI and VZV reactivation could not be analyzed because no one experienced VZV reactivation within 1 year after HSCT. More long-term large-scale multicenter study is mandatory to supplement these parts. Disclosures All Authors: No reported disclosures.

Background Methicillin-resistant Staphylococcus aureus (MRSA) colonization pressure (CP) is a useful indicator for measuring the extent of MRSA reservoir in healthcare settings. The purpose of this study is to determine the MRSA colonization rate and invasive MRSA infection rate in severely ill pediatric patients requiring pediatric intensive care unit (PICU) stay, and to evaluate the association between MRSA CP and MRSA acquisition/invasive infection. Methods From January 2016 to December 2020, pediatric patients admitted to 2 PICUs with a total of 25 beds were retrospectively analyzed. Routine nasal and/or endotracheal cultures were performed on MRSA at the time of PCIU admission and thereafter, every week. MRSA CP was defined as the ratio of the monthly MRSA positive number of patients to 100 patient days. Among MRSA colonizers, MRSA obtained after 2 days of PICU admission was defined as an acquired colonizer, and imported colonizer was defined when it was confirmed as an MRSA colonizer at the time or within 2 days of entry. When MRSA was cultured in a normally sterile body fluids, it was defined as an invasive MRSA infection. Results Of the total 6,907 patients admitted to the PICUs during this study period, 8.4% (487/6,907) were MRSA colonizers; 30% (139/487) were acquired colonizers, and invasive MRSA infections occurred in 3.3% (16/487). During the stay in the PICUs, the MRSA acquisition rate was 4.1%. A total of 22 invasive MRSA infections occurred during this study period, with an incidence rate of 3.1/1,000 patient days, of which 72.7% (n=16) occurred to the patients with MRSA colonization. Invasive MRSA infection occurred in 2.4% (8/348) of imported colonizers, and 5.2% (8/139) of acquired colonizers (p=0.108). The median duration from the time of colonization to invasive infection was 24 days(IQR; 2.25-49.75). Although MRSA CP was not correlated with the incidence of invasive MRSA infection (p=0.101), MRSA CP itself affected MRSA acquisition in PICU (p< 0.001). Conclusion MRSA CP influenced the new acquisition of MRSA during PICU stay, and newly acquired colonizers are more likely to experience invasive MRSA infection. Continuous multi-faceted efforts to minimize MRSA CP can provide opportunities for reducing MRSA colonization and infections rates in PICU settings. Disclosures All Authors: No reported disclosures.

Background Haemophilus influenzae is known to develop resistance to β-lactam antibiotics by either producing β-lactamase or modifying structure of penicillin-binding protein 3 (PBP3) by ftsI gene mutation. Since 2017, H. influenzae with ceftriaxone resistance has been continuously appearing in our hospital, and the genotypic characteristics of these strains was analyzed. Methods Among a total of 69 H. influenzae isolated from the patients who admitted to Asan Medical Center Children’s Hospital from March 2014 to April 2019, 23 isolates resistant to ceftriaxone by EUCAST disk diffusion method were included. The ceftriaxone MIC was checked again with the E-test and ceftriaxone MIC ≤ 0.125 mg/L were categorized as susceptible. As test for β-lactamase production, the cefinase test and PCR amplification for blaTEM-1 and blaROB-1 were performed. The sequencing of the ftsI encoding PBP3 amplified by PCR was performed, and amino acid sequences were compared with H. influenzae Rd KW20. Results Among total 23 ceftriaxone-resistant isolates by disk diffusion method, 21 isolates restored for further molecular characterization were included, and 19% (4/21) were reported as susceptible by E-test. Among the 21 ceftriaxone-resistant isolates, 76.2% (16/21) were non-susceptible to amoxicillin/clavulanate, and one of them were resistant to meropenem. The prevalence of b-lactamase-producers was 57.1% (12/21), all of which were positive for blaTEM-1. For ftsI gene sequencing, either R517H or N526K amino acid substitution was observed, and none had both. The number of isolates having S385T was 17, of which 15 isolates accompanied with both M377I and L389F. The median ceftriaxone MIC of 3 isolates with only N526K was 0.012 ug/ml (range 0.008-0.125 ug/ml), and 12 isolates with N526K, M377I, S385T, and L389F was 0.19 ug/ml (0.19-0.25 ug/ml). Lastly, the three isolates with R517H, M377I, S385T, and L389F showed the highest median ceftriaxone MIC with 0.25 ug/ml (0.19-0.75 ug/ml). Conclusion Ceftriaxone-resistant H. influenzae isolates in Korea seems to be related to the combination of R517H, M377I, S385T, and L389F by ftsI gene mutation. Although clinical concerns about treatment failure may be low, continuous monitoring of the emergence of highly resistant strains is necessary. Disclosures All Authors: No reported disclosures.

Background Recombinant tissue plasminogen activator (rtPA) has a short half-life, and additional hemorrhagic transformation (HT) can occur when treatment is delayed. Here, we report the design and thrombolytic performance of 3 $$\upmu$$ μ m discoidal polymeric particles loaded with rtPA and superparamagnetic iron oxide nanoparticles (SPIONs), referred to as rmDPPs, to address the HT issues of rtPA. Methods The rmDPPs consisted of a biodegradable polymeric matrix, rtPA, and SPIONs and were synthesized via a top-down fabrication. Results The rmDPPs could be concentrated at the target site with magnetic attraction, and then the rtPA could be released under acoustic stimulus. Therefore, we named that the particles had magnetoacoustic properties. For the in vitro blood clot lysis, the rmDPPs with magnetoacoustic stimuli could not enhance the lytic potential compared to the rmDPPs without stimulation. Furthermore, although the reduction of the infarcts in vivo was observed along with the magnetoacoustic stimuli in the rmDPPs, more enhancement was not achieved in comparison with the rtPA. A notable advantage of rmDPPs was shown in delayed administration of rmDPPs at poststroke. The late treatment of rmDPPs with magnetoacoustic stimuli could reduce the infarcts and lead to no additional HT issues, while rtPA alone could not show any favorable prognosis. Conclusion The rmDPPs may be advantageous in delayed treatment of thrombotic patients.

Separation anxiety is a common behavior disorder, but our understanding of its etiology and underlying neurochemical mechanisms remains limited. The purpose of this study was to compare serum brain-derived neurotrophic factor (BDNF) levels in dogs with and without separation anxiety. BDNF, one of several neurotrophins, is prevalent in the limbic region and prefrontal cortex, which are key areas related to the regulation of mood, emotion, and cognition. Although an enriched environment increases BDNF levels, stress and glucocorticoid exposure decrease the expression of BDNF in the hippocampus and prefrontal cortex. As separation anxiety is associated with chronic stress, we hypothesized that BDNF levels in dogs affected by separation anxiety would be lower than BDNF levels in nonaffected dogs. A total of forty-eight dogs were classified by a board-certified behaviorist as affected (n = 15) or nonaffected (n = 33) by separation anxiety based on review of video clips of the dogs when left alone and owner reports of the dogs’ behavior. Groups did not differ in regard to age, body weight, body condition score, or sex, and most dogs were mixed breed. Fasted serum samples were analyzed with a canine BDNF ELISA. Nine (60%) dogs in the affected group and 12 (36%) dogs in the nonaffected group had a BDNF level

Introduction: Pre-(PRE) and post-ejection (POE) velocities by mitral annular tissue Doppler (TD) are biphasic and may be related to myocardial deformations. We investigated the predominance and concordance of TD-PRE and POE velocities and their effect on myocardial functions in controls and in HF patients. Methods: Retrospectively, 84 HF patients [57.6±8 years, 28(33%) females, NYHA: 2.3±0.6, EF: 55±15%, 52(62%) preserved EF, and 32(38%) reduced EF], 42 normal young controls [27±4 years, 5(12%) females], and 26 asymptomatic age matched controls without cardiac abnormalities [53±12 years, 28(65%) females] were included. Results: While controls had almost always predominantly positive PRE and negative POE, HF had more negative PRE (Controls: 2%, HFpEF: 10%, HFrEF: 35%, p Conclusions: In physiological state, TD signals are predominantly positive during PRE and negative during POE. Opposite PRE and POE velocities corelate, representing the PRE-generation and POE-reversal of shortening-stretch relationships, the attenuation of which in HF may be related to elevated LV filling pressures. In HF, partially or completely reversed concordance of PRE and POE is associated with progressive worsening of clinical and hemodynamic profiles.

The textile industry in South Korea is characterized by excessive water consumption, high concentrations of wastewater, hazardous chemicals, and high energy consumption. This study aimed to analyze Best Available Techniques Reference Documents (BREFs) based on best available techniques (BATs) and BAT-associated emission levels (BAT-AELs) and identify potential solutions for tackling environmental pressure from the South Korean textile industry. Therefore, the existing practices of the textile dyeing and finishing industry in South Korea were compared with those from the BREFs of the European Union. Many existing BATs in South Korea are related to reducing water consumption. There is also a strong focus on BATs for reducing wastewater discharge and achieving energy-saving during treatment rather than after treatment, which differs from other industries. Moreover, BAT-AELs were derived for chemical oxygen demand, suspended solids, and total nitrogen for treating non-biodegradable, highly polluted wastewater. Furthermore, BREFs related to atmospheric pollution included dust generated from the heated fabrics in the finishing process that contained cadmium and phenolic hydrogen chloride from dyes and raw materials in the fabrics. Notably, the European Union has not specified BAT-AELs for the textile industry, whereas South Korea has tailored BAT-AELs for toxic and hazardous chemicals. Thus, numerous green techniques to reduce emissions and energy consumption are being implemented in South Korea.

Since the first synthesis curves were reported, a number of social surveys have been conducted to assess community response to noise, and determine a suitable exposure-response relationship for each socio-cultural area within different environments. Generalized exposure-response relationships have been reported using meta-analysis, which are used for predicting noise annoyance and as the basis for noise policy. However, these studies were primarily conducted in European and English-speaking communities, and studying community response in different cultural contexts is important to the development of more comprehensive exposure-response relationships. Furthermore, in some cases, case-specific exposure-relationships may better predict community response than generalized exposure-response relationships. This study presents the exposure-response relationships for the subjective annoyance of people exposed to commercial aircraft, railway, and road traffic noise for an extended period of time. Using our new analysis standard, we re-analyzed data from large-scale investigations conducted as part of a 4-year comprehensive survey comprising 52 datasets, and established modified exposure-response relationships for three types of transport noise in Korea. We found significant differences in annoyance response compared to previous studies, including the study which was used in the development process of WHO/Europe’s environmental noise guidelines. We propose that the exposure-response relationships established in our study are the most optimal curves currently available for predicting community annoyance to transportation noise in Korea. Furthermore, we suggest that future research focus on differences in annoyance responses due to the effects of non-acoustic factors.

재난약자 및 재난 특성에 따라 여성가족부, 보건복지부, 행정안전부 등 소관 부처에 따라 개별적 정책 수립 및 지원이 이루어지고 있다. 또한 재난발생시 대응 및 복구 과정에서의 재난약자에 대한 지원 대책도 갖추고 있지 않다. 이에 이 연구는 재난약자에 대한 지원체계 개선 방안 제시를 목적으로 하고 있다. 또한 연구 목적 달성을 위해, 미국, 일본 등 재난관리 선진국의 재난약자 보호 및 지원을 위한 제도 및 체계를 비교분석하여 그 시사점을 찾고자 한다. 연구의 목적을 달성하기 위해, 이 연구는 우리나라의 재난약자 지원 현황을 분석하였으며, 외국의 재난약자 지원체계 사례를 분석하여 시사점 을 도출하였다. 이 연구는 해외사례에서 도출된 시사점을 바탕으로 우리나라의 재난약자 지원체계 개선을 위한 3가지 방안을 제시하였다. 첫째 법령체계 개선과 관련하여 재난약자 관련 대상 및 업무의 명확화와 지방자치단체의 재난약자 지원 관련 조례의 개선을 제시하였다. 둘째, 재난약자 피해경감을 위하여, 재난약자 신속 대피지원 강화, 재난약자 지원을 위한 공공 및 민간 조직간 협력 강화 등이 요구된다. 셋째, 노인, 장애인, 영유아 등에 따라 주관하는 부처 및 부서가 다르기 때문에 통합적 지원체계 구축에는 어려움이 있다. 이에 재난약자 지원체계는 재난약자 지원관련 계획 수립 및 교육은 각 개별기관에서 진행하며, 지원에 필요한 인력⋅예산⋅장비 등은 총괄기관에서 담당하는 방향으로 구축하는 것이 효율적일 것으로 판단된다.

New approaches and techniques are required for environmental management in workplaces that emit pollutants. The best available techniques (BATs) that are suggested by the integrated environmental permit system (IEPS) play a pivotal role in providing state-of-the-art approaches and techniques to workplaces. For the workplaces that install facilities with the BATs, it is necessary to perform real-time monitoring to determine whether pollutant emission facilities and treatment facilities are operating normally and whether such facilities can maintain the optimal condition during the emission of pollutants. The environmental management measures used before the IEPS had limitations for workplaces that are subjected to integrated environmental management because they consider the entire workplace as a single pollution source by combining all media. In addition, only the emission concentrations and amounts of pollutants were monitored because only the points at which most pollutants are discharged, i.e., stacks for air pollutant emission facilities and final effluent outlets for water pollutant emission facilities, are monitored. These monitoring approaches in a variety of facilities involve considerable costs, and most of them (95% for stacks in workplaces under IEPS, Korea) cannot perform real-time observation even though some of them are capable of it (5% for stacks managed by Tele Monitoring System, TMS). In this study, the applicability of a wireless sensor monitoring network was examined as a new approach for environmental management in workplaces. Based on the sensor monitoring network, surrogate parameters that can indirectly monitor the critical operating factors of pollutant emission and prevention facilities were developed and then measured in real time to examine the status of these facilities. Surrogate parameters can be used instead of directly measuring pollutants as the former has high efficiency, such as cost reduction, and can provide reliable data on the emission characteristics of pollutants. The wireless network is based on an Internet of Things (IoT) platform under real-time conditions in the emission and production facilities in a workplace. This study suggested that a wireless network using the IoT platform improves the BAT assessment methodology to understand the efficiency of environmental pollution reduction and the economic contribution to the workplace.

Phosphatidylinositol 3-kinases (PI3Ks) mediate intracellular signal transduction. Aberrant PI3K signaling is associated with oncogenesis and disease progression in solid tumors and hematologic malignancies. Idelalisib (1), a first-in-class PI3Kδ inhibitor for the treatment of hematologic malignancies, was developed, but its sales were limited by black box warnings due to unexpected adverse effects. Therefore, to overcome these adverse events, various quinazolinone derivatives were synthesized and evaluated in vitro based on their inhibitory activity against the PI3K enzyme and the viability of cell lines such as MOLT and SUDHL. Among them, 6f (IC50 = 0.39 nM) and 6m (IC50 = 0.09 nM) showed excellent enzyme activity, and 6m displayed an approximately four-fold higher selectivity for PI3Kγ/δ compared with Idelalisib (1). Furthermore, in vivo PK experiments with 6f and 6m revealed that 6f (AUClast = 81.04 h*ng/mL, Cmax = 18.34 ng/mL, Tmax = 0.5 h, t1/2 = 10.2 h in 1 mpk dose) had improved PK compared with 1. Finally, further experiments will be conducted with 6f selected as a candidate, and the potential for it to be developed as a treatment with good efficacy for hematologic malignancies will be determined.

Bench-scale selective bioflotation tests were carried out in a 1 L Denver cell using Rhodococcus opacus ( R. opacus ) cells as a collector in malachite–silica binary mixture and copper (Cu) oxide ore systems. Through the first set of tests carried out on the binary mixture, cell concentration and malachite fraction in the feed were optimized, and further the role of shear force by varying impeller speed (800, 1000, and 1200 rpm) and adhesive force by varying pH (7 and 11) and ionic strength (1, 100, and 300 mM) were examined. Overall, high malachite selectivity was observed under optimized conditions (both recovery and grade > 90%). In addition, the recovery and grade of malachite were very sensitive to pH changes, with greater values being obtained at pH 7, whereas the impeller speed and the ionic strength did not seem to play a big role over the range tested. The trend was in qualitative agreement with classical Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction energy profiles, which show the relative magnitudes of the adhesive forces between the mineral and the attached cell under equal hydrodynamic conditions. The second set of tests was conducted using Cu oxide ores with two different particle sizes (74–150 μm and − 74 μm) under the optimized conditions determined from the first set of tests. The recovery and grade of malachite were found to be much greater for finer ores (recovery = 29.15% and grade = 5.17%) than those for coarser ones (recovery = 1.34% and grade = 3.06%), which is likely due to differences in malachite liberation. Further comparison of the finer ore result with that obtained from the conventional process (i.e., sulfidization followed by xanthate adsorption) indicated that the malachite selectivity of bioflotation is much higher than that of the conventional process (grade = 1.43%).

In this study, the effects of the type (ammonium sulfide (NH4)2S and sodium sulfide (Na2S)) and amount (8 × 10−5 mol/L and 2 × 10−3 mol/L) of sulfidizing reagents used in malachite flotation with xanthate as a collector on flotation recovery were investigated in a well-controlled Hallimond tube. The results showed that the average flotation recovery of malachite was similar regardless of the type of sulfidizing agent; however, a significant difference was observed when the amount of sulfidizing agents varied. Specifically, malachite had a higher flotation recovery when sulfidized at a low concentration than at a high concentration. This result was not explained by either the differences in the extent of sulfidization or by the electrostatic interaction between xanthate and malachite, which was supported by XPS and XRD analyses, adsorption tests of sulfidizing agents, and zeta potential measurements. Notably, malachite without excess sulfide ions exhibited significantly greater flotation recovery than that with excess sulfide ions regardless of the type of sulfidizing agent. These results were well supported by the results from the potentiometric titration tests, which showed greater xanthate adsorption onto the surface of malachite without excess sulfide ions than that with excess sulfide ions. Therefore, the excessive use of sulfidizing agents was confirmed to inhibit xanthate adsorption onto the malachite surface, and consequently, to decrease the flotation recovery of malachite.

We study the effects of the growth phase of Rhodococcus opacus on the floatability of malachite. We find that bacteria in stationary phase show more than two-fold higher floatability than bacteria in mid-exponential phase. To understand the mechanism of this higher floatability for the stationary phase, we examine bacteria surface properties such as zeta potential and contact angle. Surprisingly, all bacteria surface properties are nearly the same; moreover, the amounts of bacteria adsorbed onto malachite are also identical. Despite bacteria's similar surface properties, we discover that the amount of bacteria detached from malachite during the mixing process in flotation is larger for the mid-exponential phase than for the stationary phase. We attribute this to hydrodynamic shear stress due to the fluid flow established in mineral mixing. Furthermore, we observe that bacteria–bacteria interactions are far more significant for the mid-exponential phase, leading to end-to-end aggregation and thus allowing unique loosely-packed structures on the malachite surface to form. Such loose structures of bacteria on the mineral are highly susceptible to fluid flow and can be easily detached from the mineral surface. Our findings suggest that due to the relatively large size of the bacteria, it is crucial to consider the detachment of adhered bacteria on the mineral surface due to fluid flow during mixing, which is easily ignored in typical flotation processes.

Toughness and high elastic elongation are important requirements for polyimide films used as substrates in flexible displays. However, these properties can be altered by imidization during the thermal treatment. In the present study, we investigated a probable mechanism to enhance the toughness by shrinking fluorinated polyimide films containing benzidine moieties. A higher degree of fluorination leads to weaker intermolecular charge transfer and optically clearer films, but it also degrades the mechanical properties. Moreover, β -transition originating from the molecular rotation around benzidines makes the film dependent on the elongation conditions during solvent drying. According to frequency-sweeping measurements and simulations based on density functional theory and molecular dynamics, the β -transition temperature increases and the phase lag in elastic energy loss decreases with increasing shrinkage. Both experimental and theoretical findings suggest that the change in frequency dependence can be attributed to the variation in elasticity retardation, which possibly originates from the chain-entanglement density.

A novel multiplexing method, which relies on universal amplification of separated ligation-dependent probes (ASLP), has been developed to genotype single-nucleotide polymorphisms (SNPs). The ASLP technique employs two allele-specific oligonucleotides (ASO), modified with universal forward primer sequences at the 5′-end and a common locus-specific oligonucleotide (LSO) extended with a universal separation (US) sequence at the 3′-end. In the process, allele-specific ligation first takes place when target genomic DNA is hybridized by perfectly matching the ASO together with the LSO. A separation probe, which consists of a universal reverse primer sequence labeled with biotin at the 5′-end and complementary sequence of US at the 3′-end, is then applied to the resulting ligation product. During the extension reaction of the separation probe, the ligated probes dissociate from target genomic DNA in the form of a double-stranded DNA and are separated from the reaction mixture, which includes genomic DNA and unligated probes, by simply using streptavidin-coated magnetic beads. PCR amplification of the separated ligation products is then carried out by using universal primers and the PCR products are hybridized on a DNA microarray using the RecA protein. The advantageous features of the new method were demonstrated by using it to genotype 15 SNP markers for cultivar identification of pepper in a convenient and correct manner.

In this study, we investigated the adsorption isotherms of cationic surfactants (i.e., distearyl dimethyl ammonium chloride (DDAC), behenyl trimethyl ammonium chloride (BTAC), and stearyl trimethyl ammonium chloride (STAC)) onto silica surface and the corresponding silica floatability according to chain type and length of cationic surfactants. The results for the adsorption isotherms of cationic surfactants showed that the adsorptive amounts increased with increasing surfactant concentration, but differences in the position of the adsorption isotherms existed between DDAC, BTAC, and STAC. Specifically, in the high range of initial surfactant concentrations (i.e., 10 ¹5 ­10 ¹3 M), the adsorptive amounts increased with increasing hydrocarbon chain length. In addition, in the presence of DDAC, the adsorptive amounts were much greater than those in the presence of BTAC and STAC. The results were attributed to the fact that the increase in the hydrocarbon chain group of surfactants decreased the Gibbs free energy of the system, resulting in a shift of hemimicelle concentration toward lower concentration. Meanwhile, in the low range of initial surfactant concentrations (i.e., 5 © 10¹7­5 © 10¹6M), the adsorptive amounts were comparable regardless of surfactant type, which was due to the fact that the interaction between the cationic surfactants and the silica surface was mainly governed by electrostatic attractive force. The results from silica flotation and hydrophobicity tests showed that silica floatability increased with increasing hydrocarbon chain group of surfactants (i.e., floatability was in the order of DDAC > BTAC > STAC) under the conditions where the adsorptive amounts of the surfactants were comparable and that floatability results were consistent with those for the hydrophobicity of silica surface. Overall, the findings from the present study suggested that the hydrocarbon chain length and type of cationic surfactants play a significant role in both the adsorption behavior of surfactants and the silica floatability. [doi:10.2320/matertrans.M2014088]

We investigate the role of depletion interactions in the particle&ndash, bubble interactions that determine the attachment capability of particles on the bubble surface in flotation. In this article, we propose a theoretical model that explains how this attractive interaction could enhance flotation efficiency. Two optimum conditions are determined for the concentration and molecular weight of the depletion agent. The optimum concentration can be determined through the extent of surface activity of the depletion agents. The magnitude of the depletion attraction increases as the concentration increases, however, an increase in the concentration simultaneously enhances its surface concentration. The bubble surface adsorption of the depletion agent results in polymer brushes on the bubble surface that produce a large repulsive interaction. In contrast, the optimal molecular weight of the depletion agents is given by the interaction between the depletion agent sizes, which is determined by its molecular weight and Debye length which is determined by the solution ionic strength. We demonstrate that exploiting this depletion interaction could significantly enhance the flotation efficiency and in principal could be used for any particle system.

New brush polymers with various numbers of bristle ends incorporating phosphorylcholine (PC) moieties are synthesized. The polymers are thermally stable up to 175 °C and form good-quality films with conventional spin-, roll-, and dip-coating, and subsequent drying processes. Interestingly, all these brush polymers, as a PC-containing polymer, demonstrate a stable molecular multi-bilayer structure in thin films that arise due to the efficient self-assembly of the bristles for temperatures

In this study, we report the first production of two-dimensionally well-ordered molecular multilayers (i.e., with a well-defined molecular lamellar structure) based on the antiparallel beta-sheet chain conformation in thin films of a brush polypeptide, poly(S-n-hexadecyl-dl-homocysteine) (PHHC), through the use of a simple spin-coating process and the quantitative structural and property analysis of the thin films using a grazing incidence X-ray scattering technique combined with Fourier transform infrared spectroscopy and differential scanning calorimetry. These analyses provide detailed information about the structure and molecular conformation of the self-assembled lamellae in the PHHC thin film, which is not easily obtained using conventional techniques. Moreover, we used the in situ measurements carried out at various temperatures and the data analyses to establish mechanisms for the evolution of the self-assembled lamellar structures in the film and for their melting. In addition, we propose molecular structure models of the PHHC polymer molecules in the thin film at various temperatures.

In this study, a grazing-incidence X-ray scattering (GIXS) formula was derived for lamellar structures formed in thin films supported on substrates, and a comprehensive numerical analysis was performed using the scattering formula. A quantitative analysis was conducted of lamellar structures formed in nanometre-scaled thin films of a brush polymer, poly[oxy(n-decylthiomethylenyl)ethylene], supported on silicon substrates, by GIXS measurements during cooling and subsequent heating, and data analysis was performed using the scattering formula. This analysis provided details (long period, sub-layers and their thicknesses, volume fraction, bristle paracrystal distortion factor, and orientation) of the lamellar structure with varying temperature that are not easily obtained using conventional techniques. Moreover, a molecular structure model and electron density profiles were established.

The crystallization behavior of microbially synthesized poly(3-hydroxybutyrate) was studied in detail using time-resolved small-angle X-ray scattering. This polyester was found to undergo primary crystallization as well as secondary crystallization. In the primary crystallization, the thicknesses of the lamellar crystals were sensitive to the crystallization temperature, but no thickening was observed throughout the entire crystallization at a given temperature. The thickness of the lamellar crystals in the polyester was always larger than that of the amorphous layers. Secondary crystallization favorably occurred during the later stage of isothermal crystallization in competition with the continuous primary crystallization, forming secondary crystals in amorphous regions, in particular in the amorphous layers between the primarily formed lamellar crystal stacks. Compared to the primarily formed lamellar crystals, the secondary crystals had short-range-ordered structures of smaller size, a broader size distribution, and a lower electron density.

Prokaryotes were extracted from skates and fermented skates purchased from fish markets and a local manufacturer in South Korea. The prokaryotic community composition of skates and fermented skates was investigated using 16S rRNA pyrosequencing. The ranges for pH and salinity of the grinded tissue extract from fermented skates were 8.4–8.9 and 1.6–6.6%, respectively. Urea and ammonia concentrations were markedly low and high, respectively, in fermented skates compared to skates. Species richness was increased in fermented skates compared to skates. Dominant and predominant bacterial groups present in the fermented skates belonged to the phylum Firmicutes, whereas those in skates belonged to Gammaproteobacteria. The major taxa found in Firmicutes were Atopostipes (Carnobacteriaceae, Lactobacillales) and/or Tissierella (Tissierellaceae, Tissierellales). A combination of RT-PCR and pyrosequencing for active bacterial composition showed that the dominant taxa i.e., Atopostipes and Tissierella, were active in fermented skate. Those dominant taxa are possibly marine lactic acid bacteria. Marine bacteria of the taxa Lactobacillales and/or Clostridia seem to be important in alkaline fermentation of skates.

In the present study, structural analyses using synchrotron grazing incidence X-ray scattering, specular reflectivity and ellipsometry were performed on thin films of two novel polynorbornene derivatives, chiral poly(norbornene acid methyl ester) and racemic poly(norbornene acid n-butyl ester), which are potential low dielectric constant materials for advanced microelectronic and display applications. These analyses provided important information on the structure, electron density gradient across the film thickness, chain orientation, refractive index and thermal expansion characteristics of the polymers in substrate-supported thin films. The structural characteristics and properties of the thin films depended on the tacticity of the polymer chain and were further influenced by the film thickness and thermal annealing history.

Two series of brush polyimides (PIs) with various lengths of the bristles were studied as thin films using atomic force microscopy, optical retardation and linearly polarized infrared spectroscopy before and after rubbing, and their nematic liquid crystal (LC) aligning abilities were investigated: poly(p-phenylene 3,6-bis(4-(n-alkyloxy)phenyloxy)pyromellitimide)s (Cn-PMDA-PDA PIs: n = 4, 6, 7 and 8) and poly(4,4′-methylenyldiphenylene 3,6-bis(4-(n-alkyloxy)phenyloxy)pyromellitimide)s (Cm-PMDA-MDA PIs: m = 1, 4, 8 and 12). For all the PI films, the rubbing process was found to create microgrooves in the films along the rubbing direction, and to orient the polymer main chains and the n-alkyl bristle end groups along the rubbing direction, but to orient the phenyloxy bristle units perpendicular to the rubbing direction. The LC molecules on the rubbed film surfaces of Cn-PMDA-PDA PIs with n = 4, 6 and 7 were found to be aligned perpendicular to the rubbing direction. In contrast, rubbed films of Cn-PMDA-PDA PIs (n = 8) and Cm-PMDA-MDA PIs (m = 1, 4, 8 and 12) induced LC alignment parallel to the rubbing direction. These results collectively lead a conclusion that LC alignment on the rubbed PI film is determined by a play-off between the directionally anisotropic interactions the LC molecules with all possible factors associated at the film surface.

A heterogeneous zinc glutarate (ZnGA) catalyst and its derivatives were prepared from various zinc and glutarate sources. The hydrothermal reaction between zinc perchlorate hexahydrate and glutaronitrile afforded ZnGA single crystals (sc-ZnGA), with a monoclinic lattice unit cell and a P2/c space group, as determined by X-ray single-crystal structural analysis. The structural details of the ZnGA catalyst are crucial in helping to elucidate its activity in the copolymerization reactions between carbon dioxide (CO2) and alkylene oxides. X-ray absorption studies provided direct evidence that CO2 and propylene oxide (PO) are reversibly adsorbed onto the Zn ion centers on the ZnGA surface. Compared to CO2, PO was found to insert more easily into the Zn–O bond of the ZnGA catalyst, suggesting that the ZnGA-catalyzed copolymerization is initiated by PO rather than CO2. The activity of the ZnGA catalyst in the copolymerization of CO2 and PO was found to depend on the zinc source used, and its ability to produce a catalyst of large surface area and high crystallinity (≥77%). Modification of the glutarate ligand with electron-donating or withdrawing substituents failed to enhance the ZnGA catalyst activity further, indicating that glutarate is the best ligand for the Zn metal ion to achieve a high catalytic activity in the CO2 copolymerization with PO. The ZnGA-catalyzed copolymerization was further optimized to maximize the yield of alternating poly(propylene carbonate), and also extended to the terpolymerization of CO2 and PO with δ-valerolactone (VL). Terpolymers with high molecular weights and yields could be obtained by adjusting the PO/VL feed ratios. In addition, the terpolymers were found to exhibit excellent enzymatic and biological degradability.

BackgroundThe Korea Organ Donation Agency (KODA) provides various bereavement support programs to donor family. This study attempts to evaluate the effectiveness of the psychotherapy program by comparing the average scores according to the application of the psychotherapy program and to suggest the

Objective: RNA interference (RNAi)-based approaches hold great potential for cancer therapy. Here, we developed siRNA-incorporated chitosan nanoparticles coated with hyaluronic acid (HA-CH-NP/siRNA) to target CD44 receptor on the surface of tumor endothelial cells Methods: Size and zeta potential of HA-CH-NP were measured by light scattering with a particle size analyzer and Zeta Plus. Morphology of HA-CH-NP was observed by atomic force microscopy (AFM). HA-based selective binding of HA-CH-NP on the CD44 positive cells was assessed by flow cytometry and immunohistochemistry (IHC) analysis. Therapeutic efficacy was examined in orthotopic mouse models of ovarian carcinoma. PLXDC1 mRNA was quantified using real-time reverse transcription-polymerase chain reaction (RT-PCR). Additionally, biological effect on angiogenesis (MCD), cell proliferation (Ki67), and apoptosis (TUNEL) in the tumor tissue were examined by IHC analysis. Results: HA-CH-NP/siRNA was 185 ± 10 nm in size and zeta potential was 26.4 mV, respectively. The loading efficiency of siRNA into HA-CH-NP/siRNA was up to 60%. We confirmed selective binding efficiency of HA-CH-NP/siRNA with CD44+ tumor endothelial cells was increased 2.1-fold compared to CH-NP/siRNA. PLXDC1 silencing using HA-CH-NP/siRNA significantly inhibited tumor growth in A2780 tumor growth in A2780 tumor-bearing mice compared to control (p < 0.0001), and mRNA expression of PLXDC1 was significantly decreased in HA-CH-NP/siRNA treated group. In addition, treatment with HA-CH-NP/siRNA resulted in significant inhibition of cell proliferation (p < 0.05), microvessel density ( p < 0.05), and increased cell apoptosis (p < 0.05). Conclusion: This study demonstrated that HA-CH-NP/siRNA was a novel and highly selective delivery system for siRNA with potential for broad applications for tumor angiogenesis therapy. Citation Format: Gahee Kim, Heedong Han. Targeted delivery of hyaluronic acid-labeled chitosan nanoparticles against CD44 overexpressed endothelial cell for tumor angiogenesis therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2183. doi:10.1158/1538-7445.AM2017-2183

We study electrostatic interactions of polystyrene particles at an oil/water interface controlled by a chemical reaction of carboxylate surface functional groups. By replacing the carboxyl functional groups with hydrocarbon chains using the well-known EDC (1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide) coupling reaction, the surface charge density decreases while the hydrophobicity of the colloid surface increases. Direct visualization of the particle-laden interface reveals that, depending on the extent of hydrocarbon coupling, the strength of the electrostatic repulsion can be regulated: the repulsive interaction increases with the reaction, removing aggregates, but rapidly decreases if the reaction proceeds too much, forming a large aggregation. This simple reaction, thus, dramatically changes the structures of the colloidal monolayers at the oil/water interface. We conclude that such structural change is the result of change of the repulsive interactions from the oil phase, although interactions in the water phase are also changed slightly.