Enantioselective sensing by collective circular dichroism.

Quantitative determination and in situ monitoring of molecular chirality at extremely low concentrations is still challenging with simple optics because of the molecular-scale mismatch with the incident light wavelength. Advances in spectroscopy1-4 and nanophotonics have successfully lowered the detection limit in enantioselective sensing, as it can bring the microscopic chiral characteristics of molecules into the macroscopic scale5-7 or squeeze the chiral light into the subwavelength scale8-17. Conventional nanophotonic approaches depend mainly on the optical helicity density8,9 by localized resonances within an individual structure, such as localized surface plasmon resonances (LSPRs)10-16 or dielectric Mie resonances17. These approaches use the local chiral hotspots in the immediate vicinity of the structure, whereas the handedness of these hotspots varies spatially. As such, these localized resonance modes tend to be error-prone to the stochasticity of the target molecular orientations, vibrations and local concentrations18,19. Here we identified enantioselective characteristics of collective resonances (CRs)20 arising from assembled 2D crystals of isotropic, 432-symmetric chiral gold nanoparticles (helicoids)21,22. The CRs exhibit a strong and uniform chiral near field over a large volume above the 2D crystal plane, resulting from the collectively spinning, optically induced dipoles at each helicoid. Thus, energy redistribution by molecular back action on the chiral near field shifts the CRs in opposite directions, depending on the handedness of the analyte, maximizing the modulation of the collective circular dichroism (CD).

Investigating chiral morphogenesis of gold using generative cellular automata.

Homochirality is an important feature in biological systems and occurs even in inorganic nanoparticles. However, the mechanism of chirality formation and the key steps during growth are not fully understood. Here we identify two distinguishable pathways from achiral to chiral morphologies in gold nanoparticles by training an artificial neural network of cellular automata according to experimental results. We find that the chirality is initially determined by the nature of the asymmetric growth along the boundaries of enantiomeric high-index planes. The deep learning-based interpretation of chiral morphogenesis provides a theoretical understanding but also allows us to predict an unprecedented crossover pathway and the resulting morphology.

Circular polarization sensitive opto-neuromorphic operation at plasmonic hot electron transistor using chiral gold nanoparticles.

Opto-neuromorphic operation is critical for biological system to recognize the visual objects and mimicking such operation is important for artificial prosthesis as well as machine vision system for industrial applications. To sophisticatedly mimic biological system, regulation of learning and memorizing efficiency is needed, however engineered synthetic platform has been lack of controllability, which makes huge gap between biological system and synthetic platform. Here we demonstrated controllable learning and memorizing opto-neuromorphic operation at plasmonic hot electron transistor. Especially, circularly polarized light (CPL) sensitive synaptic characteristics and learning experience capability are enabled by incorporating chiral plasmonic nanoparticle. Furthermore, gate voltage gives rise to controllable neuromorphic operation due to hot electron injection and trapping effect, resulting in high remaining synaptic weight of ∼70% at negative gate voltage under CPL excitation. We believe that this discovery makes significant leap toward on-demand in-sensor computing as well as toward bio-realistic device.

Chiral plasmonic sensing: From the perspective of light-matter interaction.

Molecular chirality is represented as broken mirror symmetry in the structural orientation of constituent atoms and plays a pivotal role at every scale of nature. Since the discovery of the chiroptic property of chiral molecules, the characterization of molecular chirality is important in the fields of biology, physics, and chemistry. Over the centuries, the field of optical chiral sensing was based on chiral light-matter interactions between chiral molecules and polarized light. Starting from simple optics-based sensing, the utilization of plasmonic materials that could control local chiral light-matter interactions by squeezing light into molecules successfully facilitated chiral sensing into noninvasive, ultrasensitive, and accurate detection. In this Review, the importance of plasmonic materials and their engineering in chiral sensing are discussed based on the principle of chiral light-matter interactions and the theory of optical chirality and chiral perturbation; thus, this Review can serve as a milestone for the proper design and utilization of plasmonic nanostructures for improved chiral sensing.

Magnetic Control of the Plasmonic Chirality in Gold Helicoids.

Chiral plasmonic nanostructures have facilitated a promising method for manipulating the polarization state of light. While a precise structural modification at the nanometer-scale-level could offer chiroptic responses at various wavelength ranges, a system that allows fast response control of a given structure has been required. In this study, we constructed uniformly arranged chiral gold helicoids with cobalt thin-film deposition that exhibited a strong chiroptic response with magnetic controllability. Tunable circular dichroism (CD) values from 0.9° to 1.5° at 550 nm wavelength were achieved by reversing the magnetic field direction. In addition, a magnetic circular dichroism (MCD) study revealed that the gap structure and size-related surface plasmon resonance induced MCD peaks. We demonstrated the transmitted color modulation, where the color dynamically changed from green-to-red, by controlling the field strength and polarizer axis. We believe current work broadens our understanding of magnetoplasmonic nanostructure and expands its potential applicability in optoelectronics or optical-communications.

Production and Provision of Context-Based Patient-Specific Educational Resources.

BACKGROUND: Patient education is generally accompanied by instructive materials. The Korean government has recommended the provision of patient-specific educational materials (PEMs) via an electronic medical record (EMR) certification system. However, there are currently no clear standards or guidelines for including PEMs in current domestic educational materials. We investigated the benefits of integrating PEMs with the EMR certification system and the methods by which this integration can be achieved. METHODS: We developed and administered three structured Delphi surveys to 26 healthcare providers in clinical settings based on data collected from separate semi-structured advisory interviews with five experts. The surveys included the following topics: 1) expected effects of patient-specific education and health-related notifications/alarms, 2) desirable methods for providing PEMs, and 3) appropriate fee-setting and government support. We distributed the Delphi surveys via e-mail and calculated the average and standard deviation of the survey responses. RESULTS: PEMs are expected to have significant educational effects, such as the provision of surgery/intervention-related information, and will improve the understanding of various treatment processes/procedures. The preferred method for providing PEMs was via automatic request after receiving confirmation from healthcare providers. The provision of these materials was based on set fees and government support. The average fee per session was set at approximately USD 23 (as of October 2021, USD 1 = KRW 1,196). CONCLUSION: In this study, we investigated the prerequisites, contents, methods, and fees related to the provision of effective and efficient PEMs. The study findings can facilitate the production and provision of PEMs.

Perceived Risk of Re-Identification in OMOP-CDM Database: A Cross-Sectional Survey.

BACKGROUND: The advancement of information technology has immensely increased the quality and volume of health data. This has led to an increase in observational study, as well as to the threat of privacy invasion. Recently, a distributed research network based on the common data model (CDM) has emerged, enabling collaborative international medical research without sharing patient-level data. Although the CDM database for each institution is built inside a firewall, the risk of re-identification requires management. Hence, this study aims to elucidate the perceptions CDM users have towards CDM and risk management for re-identification. METHODS: The survey, targeted to answer specific in-depth questions on CDM, was conducted from October to November 2020. We targeted well-experienced researchers who actively use CDM. Basic statistics (total number and percent) were computed for all covariates. RESULTS: There were 33 valid respondents. Of these, 43.8% suggested additional anonymization was unnecessary beyond, "minimum cell count" policy, which obscures a cell with a value lower than certain number (usually 5) in shared results to minimize the liability of re-identification due to rare conditions. During extract-transform-load processes, 81.8% of respondents assumed structured data is under control from the risk of re-identification. However, respondents noted that date of birth and death were highly re-identifiable information. The majority of respondents (n = 22, 66.7%) conceded the possibility of identifier-contained unstructured data in the NOTE table. CONCLUSION: Overall, CDM users generally attributed high reliability for privacy protection to the intrinsic nature of CDM. There was little demand for additional de-identification methods. However, unstructured data in the CDM were suspected to have risks. The necessity for a coordinating consortium to define and manage the re-identification risk of CDM was urged.

Spin angular momentum-encoded single-photon emitters in a chiral nanoparticle-coupled WSe2 monolayer.

Spin angular momentum (SAM)-encoded single-photon emitters, also known as circularly polarized single photons, are basic building blocks for the advancement of chiral quantum optics and cryptography. Despite substantial efforts such as coupling quantum emitters to grating-like optical metasurfaces and applying intense magnetic fields, it remains challenging to generate circularly polarized single photons from a subwavelength-scale nanostructure in the absence of a magnetic field. Here, we demonstrate single-photon emitters encoded with SAM in a strained WSe2 monolayer coupled with chiral plasmonic gold nanoparticles. Single-photon emissions were observed at the nanoparticle position, exhibiting photon antibunching behavior with a g(2)(0) value of ~0.3 and circular polarization properties with a slight preference for left-circular polarization. Specifically, the measured Stokes parameters confirmed strong circular polarization characteristics, in contrast to emitters coupled with achiral gold nanocubes. Therefore, this work provides potential insights to make SAM-encoded single-photon emitters and understand the interaction of plasmonic dipoles and single photons, facilitating the development of chiral quantum optics.

Examining Final-Administered Medication as a Measure of Data Quality: A Comparative Analysis of Death Data with the Central Cancer Registry in Republic of Korea.

Death is a crucial outcome in retrospective cohort studies, serving as a criterion for analyzing mortality in a database. This study aimed to assess the quality of extracted death data and investigate the potential of the final-administered medication as a variable to quantify accuracy for the validation dataset. Electronic health records from both an in-hospital and the Korean Central Cancer Registry were used for this study. The gold standard was established by examining the differences between the dates of in-hospital deaths and cancer-registered deaths. Cosine similarity was employed to quantify the final-administered medication similarities between the gold standard and other cohorts. The gold standard was determined as patients who died in the hospital after 2006 and whose final hospital visit/discharge date and death date differed by 0 or 1 day. For all three criteria-(a) cancer stage, (b) cancer type, and (c) type of final visit-there was a positive correlation between mortality rates and the similarities of the final-administered medication. This study introduces a measure that can provide additional accurate information regarding death and differentiates the reliability of the dataset.

Neural-Network-Enabled Design of a Chiral Plasmonic Nanodimer for Target-Specific Chirality Sensing.

Quantitative analysis of chiral molecules in various solvents is essential. However, there are still many challenges to enhancing the sensitivity in precisely determining both concentration and chirality. Here, we built an algorithmic methodology to predict and optimally design the chiroptical response of chiral plasmonic sensors for a specific target chiral analyte with the aid of deep learning. Based upon the analytic and intuitive understanding of the Born-Kuhn type plasmonic nanodimer, we designed and trained the neural networks that can successfully predict the chiroptical properties and further inversely design the plasmonic structure to achieve the intended circular dichroism. The developed algorithm could identify the optimum structure exhibiting the maximum sensitivity for the given specific analytes. Surprisingly, we discovered that sensitivity strongly depends on the various conditions of analytes and can be finely tuned with the structural parameters of plasmonic nanodimers. We envision that this study can provide a general platform to develop ultrasensitive chiral plasmonic sensors whose structure and sensitivity have been evolved algorithmically for adoption in specific applications.

Strain and crystallographic identification of the helically concaved gap surfaces of chiral nanoparticles.

Identifying the three-dimensional (3D) crystal plane and strain-field distributions of nanocrystals is essential for optical, catalytic, and electronic applications. However, it remains a challenge to image concave surfaces of nanoparticles. Here, we develop a methodology for visualizing the 3D information of chiral gold nanoparticles ≈ 200 nm in size with concave gap structures by Bragg coherent X-ray diffraction imaging. The distribution of the high-Miller-index planes constituting the concave chiral gap is precisely determined. The highly strained region adjacent to the chiral gaps is resolved, which was correlated to the 432-symmetric morphology of the nanoparticles and its corresponding plasmonic properties are numerically predicted from the atomically defined structures. This approach can serve as a comprehensive characterization platform for visualizing the 3D crystallographic and strain distributions of nanoparticles with a few hundred nanometers, especially for applications where structural complexity and local heterogeneity are major determinants, as exemplified in plasmonics.

Adenine oligomer directed synthesis of chiral gold nanoparticles.

Precise control of morphology and optical response of 3-dimensional chiral nanoparticles remain as a significant challenge. This work demonstrates chiral gold nanoparticle synthesis using single-stranded oligonucleotide as a chiral shape modifier. The homo-oligonucleotide composed of Adenine nucleobase specifically show a distinct chirality development with a dissymmetric factor up to g ~ 0.04 at visible wavelength, whereas other nucleobases show no development of chirality. The synthesized nanoparticle shows a counter-clockwise rotation of generated chiral arms with approximately 200 nm edge length. The molecular dynamics and density functional theory simulations reveal that Adenine shows the highest enantioselective interaction with Au(321)R/S facet in terms of binding orientation and affinity. This is attributed to the formation of sequence-specific intra-strand hydrogen bonding between nucleobases. We also found that different sequence programming of Adenine-and Cytosine-based oligomers result in chiral gold nanoparticles' morphological and optical change. These results extend our understanding of the biomolecule-directed synthesis of chiral gold nanoparticles to sequence programmable deoxyribonucleic acid and provides a foundation for programmable synthesis of chiral gold nanoparticles.

Comparison of the novel human papillomavirus 4 auto-capillary electrophoresis test with the hybrid capture 2 assay and with the PCR HPV typing set test in the detection of high-risk HPV including HPV 16 and 18 genotypes in cervical specimens.

The aim of this study was to compare the novel human papillomavirus (HPV) detection method, the HPV 4 Auto-capillary Electrophoresis (ACE) test with the hybrid capture (HC) 2 assay for the detection of high-risk HPVs. In addition, we compared the HPV 4 ACE test with the polymerase chain reaction HPV Typing Set test for the detection of HPV 16 and HPV 18 genotypes. One hundred ninety-nine cervical swab samples obtained from women with previous abnormal Pap smears were subjected to testing with the three HPV tests. The HPV 4 ACE test and the HC 2 assay showed substantial agreement for detection of high-risk HPVs (85.4%, kappa=0.71). The HPV 4 ACE test also showed substantial agreement with the PCR HPV Typing Set test in the detection of HPV 16 and HP V 18 genotypes (89.9%, kappa=0.65). In correlation with cytologic results, the sensitivities and specificities of the HPV 4 ACE test and HC 2 assay were 92.9% vs. 92.9% and 48.1% vs. 50.8%, respectively, when high-grade squamous intraepithelial lesions were regarded as abnormal cytologies. The novel HPV 4 ACE test is a valuable tool for the detection of high-risk HPVs and for genotyping of HPV 16 and HPV 18.

Purification, characterization and molecular cloning of Vibrio fluvialis hemolysin.

Hemolysin of Vibrio fluvialis (VFH) was purified from culture supernatants by ammonium sulfate precipitation and successive column chromatographies on DEAE-cellulose and Mono-Q. N-terminal amino acid sequences of the purified VFH were determined. The purified protein exhibited hemolytic activity on many mammalian erythrocytes with rabbit erythrocytes being the most sensitive to VFH. Activity of the native VFH was inhibited by the addition of Zn2+, Ni2+, Cd2+ and Cu2+ ions at low concentrations. Pores formed on rabbit erythrocytes were approximately 2.8-3.7 nm in diameter, as demonstrated by osmotic protection assay. Nucleotide sequence analysis of the vfh gene revealed an open reading frame (ORF) consisting of 2200 bp which encodes a protein of 740 amino acids with a molecular weight of 82 kDa. Molecular weight of the purified VFH was estimated to be 79 kDa by SDS-PAGE and N-terminal amino acid sequence revealed that the 82 kDa prehemolysin is synthesized in the cytoplasm and is then secreted into the extracellular environment as the 79 kDa mature hemolysin after cleavage of 25 N-terminal amino acids. Deletion of 70 amino acids from the C-terminus exhibited a smaller hemolytic activity, while deletion of 148 C-terminal amino acids prevented hemolytic activity.

Dual priming oligonucleotide-based multiplex PCR analysis for detection of BRAFV600E mutation in FNAB samples of thyroid nodules in BRAFV600E mutation-prevalent area.

BACKGROUND: To evaluate the diagnostic value of dual priming oligonucleotide (DPO)-based multiplex polymerase chain reaction (PCR) for the detection of BRAF(V600E) mutations in ultrasound-guided fine-needle aspiration biopsy (US-FNAB) of thyroid nodules. METHODS: Our institutional review board approved this retrospective study, and informed consent was not required from patients. The 130 patients underwent US-FNAB to evaluate BRAF status in thyroid nodules. In FNAB washouts, DPO-based multiplex PCR, direct DNA sequencing, and PCR-restriction fragment length polymorphism (RFLP) were used to detect BRAF(V600E). The diagnostic performance of these methods was calculated. We compared cytologic results by BRAF status. RESULTS: Diagnostic accuracy and sensitivity were highest when screening with DPO-based multiplex PCR. BRAF(V600E) positivity was a useful marker at thyroid nodules with "suspicious for papillary thyroid carcinoma" or "inadequate" cytological result. CONCLUSIONS: DPO-based multiplex PCR may be an alternative to direct DNA sequencing because of its high sensitivity, high accuracy, and simplicity. BRAF(V600E) may be a useful additional diagnostic marker in BRAF(V600E)-prevalent areas.

Detection of a novel CBFB/MYH11 variant fusion transcript (K-type) showing partial insertion of exon 6 of CBFB gene using two commercially available multiplex RT-PCR kits.

We report on a 20-year-old man with acute myeloid leukemia (AML) showing a distinct novel CBFB/MYH11 variant fusion transcript. Initial results of bone marrow, chromosome, and flow cytometric analyses were not in accordance with the diagnosis of acute myelomonocytic leukemia with eosinophilia (AML-M4Eo) or AML with a CBFB/MYH11 rearrangement. However, results from 2 commercially available multiplex reverse transcriptase-polymerase chain reaction (RT-PCR) tests repeatedly showed an unusual PCR product from his bone marrow specimen. Not only does this case show a partial insertion of exon 6 of the CBFB (ENSG00000067955) gene, but it also involves novel breakpoints within both exon 6 of the CBFB gene and exon 28 (previously exon 7) of the MYH11 (ENSG00000133392) gene, which is regarded as a previously non-reported, new type (K-type) of CBFB/MYH11 fusion transcript. In addition, our study result was in agreement with the recent report of Schnittger et al. that rare fusion transcripts of CBFB/MYH11 are correlated with an atypical cytomorphology and other aberrant characteristics. Therefore, multiplex RT-PCR and sequence analysis of these atypical products should be performed to diagnose atypical AML with CBFB/MYH11 rearrangement, to predict prognosis of these patients as well as to elucidate the molecular mechanism.

Acute promyelocytic leukemia in early pregnancy with translocation t(15;17) and variant PML/RARA fusion transcripts.

A 32-year-old pregnant woman in the 13th gestational week was brought to Severance Hospital with gum bleeding and easy bruising. Initial laboratory results revealed anemia and thrombocytopenia. In a peripheral blood smear, 81% of leukocytes were large, abnormal promyelocytes. Bone marrow aspiration showed a hypercellular marrow with packed leukemic promyelocytes, and chromosome study revealed a karyotype of 46,XX,t(15;17)(q22;q21)[10]/46,XX[10]. In addition, variant fusion transcripts of PML/RARA were detected in the marrow specimen. The patient was diagnosed with acute promyelocytic leukemia (APL) and was treated with all-trans retinoic acid (ATRA) and idarubicin. One month from the patient's initial diagnosis a follow-up bone marrow examination was performed, revealing complete remission (CR). We know of no previous reports of APL during pregnancy associated with variant PML/RARA fusion transcripts. Here, we describe a novel case of APL in a pregnant woman with a t(15;17) translocation and variant fusion transcripts.

Identification of an iron-regulated hemin-binding outer membrane protein, HupO, in Vibrio fluvialis: effects on hemolytic activity and the oxidative stress response.

In pathogenic bacteria, iron acquisition is important for colonization and proliferation in the host under iron-limited conditions. The ability of Vibrio spp. to acquire iron is often critical to their virulence, causing gastroenteritis or excessive watery diarrhea in humans. In the study described here, we cloned the 2,100-bp heme utilization protein gene hupO in Vibrio fluvialis. HupO had high homology to iron-regulated outer membrane receptor proteins in Vibrio sp. and contained motifs that are common to bacterial heme receptors, including a consensus TonB box, a FRAP domain, and an NPNL domain. To characterize the hemin-binding activity of HupO, we purified the recombinant HupO protein (rHupO) from Escherichia coli by using an overexpression system. HupO was found to bind to hemin but not to hemoglobin. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting demonstrated that the 77-kDa outer membrane protein HupO of V. fluvialis was induced under iron-restricted conditions. We constructed a hupO mutant, HP1, to investigate the biochemical function of HupO in V. fluvialis. The hemolytic activity of HP1 was reduced compared to that of wild-type cells and, when exposed to hydrogen peroxide, significantly lower numbers of HP1 survived than was the case in the wild type. These results suggest that HupO is associated with virulence expression in V. fluvialis through stimulation of hemolysin production and resistance to oxidative stress. In experimentally infected mice, the 50% lethal dose value of the wild-type was lower than that of the mutant, HP1.