Search

The recent emerging significance of the Internet of Things (IoT) demands sensor devices to be integrated with many different functional structures and devices while conserving their original functionalities. To this end, optical transparency and mechanical flexibility of sensor devices are critical requirements for optimal integration as well as high sensitivity. In this work, a transparent, flexible, and sensitive gas sensor building platform is introduced by using multilevel self-assembly of block copolymers (BCPs) and polystyrene (PS) colloids. For the demonstration of an H

Air pollution is on the priority list of global safety issues, with the concern of fatal environmental and public health deterioration. 2D materials are potential adsorbent materials for environmental decontamination, owing to their high surface area, manageable interlayer binding, large surface-to-volume ratio, specific binding capability, and chemical, thermal, and mechanistic stability. Specifically, graphene oxide and reduced graphene oxide have been attracting attention, taking advantage of their low cost synthesis, excessive oxygen containing surface functionalities, and intrinsic aqueous dispersibility, making them desirable for the development of cost-effective, high performance air filters. Many different material designs have been proposed to expand their filtration capability, including the functionalization and integration with other metals and metal oxides, which act not only as binding agents to the target pollutants but also as antimicrobial agents. This review highlights the advantages and drawbacks of 2D materials for air filtration and summarizes the interrelationships among various strategies and the resultant filtration performance in terms of structural engineering, morphology control, and material compositions. Finally, potential future directions are suggested toward the idealized designs of 2D material based air filters.

Hardware-based cryptography that exploits physical unclonable functions is required for the secure identification and authentication of devices in the Internet of Things. However, physical unclonable functions are typically based on anticounterfeit identifiers created from randomized microscale patterns or non-predictable fluctuations of electrical response in semiconductor devices, and the validation of an encrypted signature relies on a single-purpose method such as microscopy or electrical measurement. Here we report nanoscale physical unclonable function labels that exploit non-deterministic molecular self-assembly. The labels are created from the multilayer superpositions of metallic nanopatterns replicated from self-assembled block copolymer nanotemplates. Due to the nanoscale dimensions and diverse material options of the system, physical unclonable functions are intrinsically difficult to replicate, robust for authentication and resistant to external disturbance. Multiple, independently operating keys—which use electrical resistance, optical dichroism or Raman signals—can be generated from a single physical unclonable function, offering millisecond-level validation speeds. We also show that our physical unclonable function labels can be used on a range of different surfaces including dollar bills, human hair and microscopic bacteria.

Block copolymer (BCP) nanopatterning has emerged as a versatile nanoscale fabrication tool for semiconductor devices and other applications, because of its ability to organize well-defined, periodic nanostructures with a critical dimension of 5-100 nm. While the most promising application field of BCP nanopatterning has been semiconductor devices, the versatility of BCPs has also led to enormous interest from a broad spectrum of other application areas. In particular, the intrinsically low cost and straightforward processing of BCP nanopatterning have been widely recognized for their large-area parallel formation of dense nanoscale features, which clearly contrasts that of sophisticated processing steps of the typical photolithographic process, including EUV lithography. In this Review, we highlight the recent progress in the field of BCP nanopatterning for various nonsemiconductor applications. Notable examples relying on BCP nanopatterning, including nanocatalysts, sensors, optics, energy devices, membranes, surface modifications and other emerging applications, are summarized. We further discuss the current limitations of BCP nanopatterning and suggest future research directions to open up new potential application fields.

Nanoscale shape engineering is an essential requirement for the practical use of 2D materials, aiming at precisely customizing optimal structures and properties. In this work, sub-10-nm-scale block copolymer (BCP) self-assembled nanopatterns finely aligned along the atomic edge of 2D flakes, including graphene, MoS

Graphene oxide (GO)-a chemical derivative of graphene with numerous oxygen functional groups on its surface-has attracted considerable interest because of its intriguing properties in relation to those of pristine graphene. In addition to the inherent wide lateral size distribution of GO sheets arising from the typical oxidative exfoliation of graphite, control of the lateral size of GO is critical for desired GO-based applications. Herein, flow/hyperlayer field-flow fractionation (flow/hyperlayer FFF) is optimized to separate GO sheets by lateral dimensions. Optimized fractionation is achieved by investigating the influences of carrier solvent, channel thickness, and flow rate conditions on the steric/hyperlayer separation of GO sheets by flow FFF. Due to the strong hydrodynamic lift forces of extremely thin GO sheets, a thick flow FFF channel (w = 350 μm) and a very low field strength are required to retain the GO sheets within the channel. GO sheets with narrow size fractions are successfully collected from two different graphite sources during flow/hyperlayer FFF runs and are examined to verify the size evolution. Considering the average lateral diameter of the GO fraction calculated on the basis of the assumption of a circular disk shape, the retention of the GO sheets is 2.2-5.0 times faster than that of spherical particles of the same diameter. This study demonstrates that through flow/hyperlayer FFF, the size distribution of GO sheets can be determined and narrow size fractions can be collected (which is desirable for GO-based applications), which are commonly influenced by the GO lateral dimension.

Sustainable methods that increase farmed fish yield while controlling infections are required to prevent economic losses in aquaculture farms. In this study, we evaluated the effects of betaine-supplemented (0%, 0.1%, 0.5%, and 1.0%) feed on the growth and immunity of the olive flounder Paralichthys olivaceus. Feed conversion ratios, post-infection cumulative mortality rates and innate immune responses were monitored. Weight gain was significantly higher with 0.5% and 1.0% than with 0% and 0.1% betaine-supplemented feed. Lysozyme activity was highest with 1.0% betaine. Respiratory burst activity was highest with 0.5% and 1.0% betaine. Serum bactericidal activity against Edwardsiella tarda was highest with 1.0% betaine (40% increase in survival rates compared with those in the control). Furthermore, serum virucidal activity against the viral haemorrhagic septicaemia virus (VHSV) was higher with 1.0% betaine than with other concentrations. With 0.5% and 1.0% betaine, the survival rates against VHSV were higher than those in the control until day 11, after which they declined. Our study suggests that betaine is a promising agent for promoting the growth of and enhancing immunity against E. tarda in olive flounders. Our findings may further contribute to developing necessary alternatives to conventional antibiotics in fish farming.

AIMS Enalapril is a prodrug and needs to be activated by carboxylesterase 1 (CES1). A previous in vitro study demonstrated the CES1 genetic variant, G143E (rs71647871), significantly impaired enalapril activation. Two previous clinical studies examined the impact of G143E on single-dose enalapril PK (10 mg); however, the results were inconclusive. A prospective, multi-dose, pharmacokinetics and pharmacodynamics (PK/PD) study was conducted to determine the impact of the CES1 G143E variant on enalapril steady-state PK and PD in healthy volunteers. METHODS Study participants were stratified to G143E non-carriers (n = 15) and G143E carriers (n = 6). All the carriers were G143E heterozygotes. Study subjects received enalapril 10 mg daily for seven consecutive days prior to a 72 hour PK/PD study. Plasma concentrations of enalapril and its active metabolite enalaprilat were quantified by an established liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. RESULTS The CES1 G143E carriers had 30.9% lower enalaprilat Cmax (P = 0.03) compared to the non-carriers (38.01 vs. 55.01 ng/mL). The carrier group had 27.5% lower AUC0-∞ (P = 0.02) of plasma enalaprilat compared to the non-carriers (374.29 vs. 515.91 ng*h/mL). The carriers also had a 32.3% lower enalaprilat-to-enalapril AUC0-∞ ratio (P = 0.003) relative to the non-carriers. The average maximum reduction of systolic blood pressure in the non-carrier group was approximately 12.4% at the end of the study compared to the baseline (P = 0.001). No statistically significant blood pressure reduction was observed in the G143E carriers. CONCLUSIONS The CES1 loss-of-function G143E variant significantly impaired enalapril activation and its systolic blood pressure-lowering effect in healthy volunteers.

Many interesting properties of 2D materials and their assembled structures are strongly dependent on the lateral size and size distribution of 2D materials. Accordingly, effective size separation of polydisperse 2D sheets is critical for desirable applications. Here, we introduce flow field-flow fractionation (FlFFF) for a wide-range size fractionation of graphene oxide (GO) up to 100 μm. Two different separation mechanisms are identified for FlFFF, including normal mode and steric/hyperlayer mode, to size fractionate wide size-distributed GOs while employing a crossflow field for either diffusion or size-controlled migration of GO. Obviously, the 2D GO sheet reveals size separation behavior distinctive from typical spherical particles arising from its innate planar geometry. We also investigate 2D sheet size-dependent mechanical and electrical properties of three different graphene fibers produced from size-fractionated GOs. This FlFFF-based size selection methodology can be used as a generic approach for effective wide-range size separation for 2D materials, including rGO, TMDs, and MXene.

Background Live fish import may lead to the unintended introduction of pathogens. We examined the monthly distribution of microbial pathogens in ornamental finfish imported into South Korea over a 6-month period. Results Vibrio alginolyticus was detected in one lemon damsel in June and July; V. vulnificus was detected in one lemon damsel, one caerulean damsel, and one pearl-spot chromis and one ocellaris clownfish in July, April, and May, respectively; Photobacterium damselae was detected in one ocellaris clownfish and one caerulean damsel in June and July, respectively; V. anguillarum was detected in one pearl-spot chromis in February; V. harveyi was detected in one ocellaris clownfish and two mandarin fish in February and April, respectively; Yersinia ruckeri was detected in a pearlscale goldfish group in June and July and in two colored carp groups in July; and Lactococcus garvieae was detected in a lemon damsel group and a sutchi catfish group in July and May, respectively. European catfish virus, the only viral pathogen detected, was found in two sutchi catfish groups in May. Conclusion This study is the first to identify pathogenic species and the presence or absence of pathogens (non-quarantine diseases) in imported ornamental finfish. These results demonstrate that various pathogens with the potential to harm indigenous fish populations can accompany ornamental finfish imported into South Korea.

Nanoscale engineering of carbon materials is immensely demanded in various scientific areas. We present highly ordered nitrogen-doped carbon nanowire arrays via block copolymer (BCP) self-assembly under an electric field. Large dielectric constant difference between distinct polymer blocks offers rapid alignment of PMMA-b-PAN self-assembled nanodomains under an electric field. Lithographic patterning of the graphene electrode as well as straightforward thermal carbonization of the PAN block creates well-aligned carbon nanowire device structures. Diverse carbon nanopatterns including radial and curved arrays can be readily assembled by the modification of electrode shapes. Our carbon nanopatterns bear a nitrogen content over 26%, highly desirable for NO2 sensing, as the nitrogen element acts as adsorption sites for NO2 molecules. Aligned carbon nanowire arrays exhibits a 6-fold enhancement of NO2 sensitivity from a randomly aligned counterpart. Taking advantage of well-established benefits from device-oriented BCP nanopatterning, our approach proposes a viable route to highly ordered carbon nanostructures compatible to next-generation device architectures.

The annual rate of ornamental aquatic crustacean importation is increasing globally. The continuous high demand for live ornamental aquatic crustaceans in many countries has also increased the frequency of imported exotic pathogens, which has caused many problems. In the present study, we examined the monthly distribution of viral and bacterial pathogen genes in ornamental aquatic crustaceans imported into South Korea during a 6-month period from February to July 2016. Among the bacterial pathogens identified, Vibrio alginolyticus was detected in cleaner shrimp in June, and Photobacterium damselae was detected in cleaner shrimp in July. Vibrio penaeicida was detected in peppermint shrimp, banded coral shrimp, hinge-beak shrimp, and orange swamp crayfish between February and June. Among the viral pathogens identified, spawner mortality virus was detected in cherry shrimp in May. Finally, hepatopancreatic parvovirus was detected in both cherry shrimp and orange swamp crayfish between February and March. Notably, the genes of two viral pathogens were also detected in cherry shrimp. Although the viruses were not isolated, they are very likely to have been introduced into South Korea and have an influence on Korean aquaculture. In South Korea, HPV is already prevalent and has been reported several times in aquaculture and in the wild; however, SMV infection has not been reported to date. These results demonstrate that many bacterial and viral pathogens are regularly introduced into South Korea via the ornamental aquatic-crustacean trade.

The causes of homelessness are complex and poorly understood. This paper describes the homeless population in Santa Clara County, California in terms of Adverse Childhood Events, Traumatic Brain Injuries (TBIs), and family breakdown. Respondents reported severely traumatic childhoods; 78.7% grew up in a household with a person with drug or alcohol dependence and 64.6% endured psychological abuse as a child. Seventy-six percent of subjects recalled at least one TBI, 58.4% with loss of consciousness. Nineteen percent were in foster care as children and 40.2% reported having someone other than a parent as a primary caregiver. Fifty-three percent felt they had moved too much as children, and 37.5% had experienced homelessness as children. Santa Clara County has both the highest median income and the highest rate of unsheltered homelessness in the nation. Leaders and community members should work together to improve the lives of the home-less and to prevent another generation of homeless people.

Anaerobes are an important but uncommon cause of bloodstream infections (BSIs). For pediatric patients, routine inclusion of an anaerobic blood culture alongside the aerobic remains controversial. We implemented automatic anaerobic blood culture alongside aerobic blood cultures in a pediatric emergency department (ED) and sought to determine changes in recovery of obligate and facultative anaerobes. This was a cohort study in a pediatric ED (August 2015 to July 2018) that began in February 2017. Blood culture positivity results for true pathogens and contaminants were assessed, along with a secondary outcome of time to positivity (TTP) of blood culture. A total of 14,180 blood cultures (5,202 preimplementation and 8,978 postimplementation) were collected, with 8.8% (456) and 7.1% (635) positive cultures in the pre- and postimplementation phases, respectively. Of 635 positive cultures in the postimplementation phase, aerobic blood cultures recovered 7.6% (349/4,615), whereas anaerobic blood cultures recovered 6.6% (286/4,363). In 211/421 (50.0%) paired blood cultures, an organism was recovered in both cultures. The number of cases where organisms were only recovered from an aerobic or an anaerobic bottle in the paired cultures were 126 (30.0%) and 84 (20.0%), respectively. The TTP was comparable regardless of bottle type. Recovery of true pathogens from blood cultures was approximately 7 h faster than recovery of contaminants. Although inclusion of anaerobic blood cultures only recovered 2 (0.69%) obligate anaerobes, it did allow for recovery of clinically significant pathogens that were negative in aerobic blood cultures and supports the routine collection of both bottles in pediatric patients with a concern of bloodstream infections.

Block copolymer (BCP) lithography is an effective nanopatterning methodology exploiting nanoscale self-assembled periodic patterns in BCP thin films. This approach has a critical limitation for nonplanar substrate geometry arising from the reflow and modification of BCP films upon the thermal or solvent annealing process, which is inevitable to induce the mobility of BCP chains for the self-assembly process. Herein, reflow-free, 3D BCP nanopatterning is demonstrated by introducing a conformally grown adlayer by the initiated chemical vapor deposition (iCVD) process. A highly cross-linked poly(divinylbenzene) layer was deposited directly onto the BCP thin film surface by iCVD, which effectively prevented the reflow of BCP thin film during an annealing process. BCP nanopatterns could be stabilized on various substrate geometry, including a nonplanar deformed polymer substrate, a pyramid shape substrate, and a graphene fiber surface. A fiber-type hydrogen evolution reaction (HER) catalyst is suggested by stabilizing lamellar Pt nanopatterns on severely rough graphene fiber surfaces.

The olive flounder (Paralichthys olivaceus) is an economically important marine fish species in several East Asian countries. Previously, some cell lines have been derived from the olive flounder, which have shown sensitivity to some viral infections that occur in the fish. In this study, we generated a new immortal cell line, named Korea fin Tissue from Sea flounder (KTS), from the fin tissues of olive flounder and successfully subcultured the cells approximately 250 times over 4 years. KTS cells displayed stable growth at temperatures ranging from 25 °C to 31 °C, with optimum growth at 27 °C. Thus, this cell line has a relatively higher and wider range of growth temperatures compared with other reported cell lines. Chromosome analysis showed that the cell line contains 46 chromosomes, which is fewer than those in other cell lines derived from olive flounder. Furthermore, we evaluated the susceptibility of the cell line to infectious viruses such as viral hemorrhagic septicemia virus (VHSV), infectious hematopoietic necrosis virus (IHNV), hirame rhabdovirus (HRRV), and marine birnavirus (MABV). KTS cells showed 100% cytopathic effect (CPE) at 2 weeks. Notably, KTS cells stimulated with CpG-ODN1668 or poly (I:C) showed higher expression of immune genes in the cytoplasm that were recognized by Toll-like receptor 3 (TLR3) or TLR9. These results suggested that the KTS cell line is promising for immune gene expression analysis and other genetic studies. In conclusion, we successfully generated an immortal cell line from the fin tissue of olive flounder. KTS cells have a higher growth temperature range than other reported cell lines, which could prove useful for future cytopathological, genetic, and infectious viral mechanistic studies in this species.

We aimed to explore the perceived timeliness of referral to hospice palliative care unit (HPCU) among bereaved family members in Korea and factors associated therewith.Cross-sectional questionnaire survey was performed for bereaved family members of patients who utilized 40 designated HPCUs across Korea. The questionnaire assessed whether admission to the HPCU was "too late" or "appropriate" and the Good Death Inventory (GDI).A total of 383 questionnaires were analyzed. Of participants, 25.8 % replied that admission to HPCU was too late. Patients with hepatobiliary cancer, poor performance status, abnormal consciousness level, and unawareness of terminal status were significantly related with the too late perception. Family members with younger age and being a child of the patient were more frequently noted in the too late group. Ten out of 18 GDI scores were significantly lower in the too late group. Multiple logistic regression analysis revealed patients' unawareness of terminal status, shorter stay in the HPCU, younger age of bereaved family, and lower scores for two GDI items (staying in a favored place, living without concerning death or disease) were significantly associated with the too late group.To promote timely HPCU utilization and better quality of end of life care, patients need to be informed of the terminal status and their preference should be respected.

Blogs are a new type of media that have recently become popular on the World Wide Web and have influence throughout society. The purpose of this study is to examine social motivations influencing intention of blog usage. Based on Technology Acceptance Model and Motivation Theory, this study considered perceived usefulness, perceived ease of use, reputation, reciprocity, enjoyment of helping, social identity as the determinants of influencing the intention to use of blog. The suggested model was empirically evaluated using online survey data collection from 342 users of popular blog site in Korea (NAVER Blog, Cyworld minihompy, Daum Blog, and Yahoo Blog). The results revealed that perceived usefulness, perceived ease of use, reciprocity, and social identity affect directly the intention of blog usage. Furthermore, social identity has moderate effect via reciprocity and enjoyment of helping on blog usage. This study contributes to a theoretical understanding of the factors as social motivation that affects the usage of blogs. Also, the results of this study provide blog service providers useful strategic insights and service guidelines to enhance user`s intention of blogs practically.

The potential for short-term training to improve cognitive and sensory functions in older adults has captured the public's interest. Initial results have been promising. For example, eight weeks of auditory-based cognitive training decreases peak latencies and peak variability in neural responses to speech presented in a background of noise and instills gains in speed of processing, speech-in-noise recognition, and short-term memory in older adults. But while previous studies have demonstrated short-term plasticity in older adults, we must consider the long-term maintenance of training gains. To evaluate training maintenance, we invited participants from an earlier training study to return for follow-up testing six months after the completion of training. We found that improvements in response peak timing to speech in noise and speed of processing were maintained, but the participants did not maintain speech-in-noise recognition or memory gains. Future studies should consider factors that are important for training maintenance, including the nature of the training, compliance with the training schedule, and the need for booster sessions after the completion of primary training.