Development of Ocular Muscle Stimulation Systems and Optimization of Electrical Stimulus Parameters for Paralytic Strabismus Treatment.

Paralysis of the extraocular muscles can lead to complications such as strabismus, diplopia, and loss of stereopsis. Current surgical treatments aim to mitigate these issues by resecting the paralyzed muscle or transposing the other recti muscles to the paralyzed muscle, but they do not fully improve the patient's quality of life. Electrical stimulation shows promise, while requiring further in vivo experiments and research on various stimulation parameters. In this study, we conducted experiments on rabbits to stimulate the superior rectus (SR) muscles using different parameters and stimulation waveforms. To provide various types of electrical stimulation, we developed the ocular muscle stimulation systems capable of both current controlled stimulation (CCS) and high-frequency stimulation (HFS), along with the chip that enables energy-efficient and safe switched-capacitor stimulation (SCS). We also developed electrodes for easy implantation and employed safe and efficient stimulation methods including CCS, SCS, and HFS. The in vivo animal experiments on normal and paralyzed SR muscles of rabbits showed that eyeball abduction angles were proportional to the current and pulse width of the stimulation. With the decaying exponential stimuli of the SCS system, eyeball abductions were 2.58× and 5.65× larger for normal and paralyzed muscles, respectively, compared to the rectangular stimulus of CCS. HFS achieved 0.92× and 0.26× abduction for normal and paralyzed muscles, respectively, with half energy compared to CCS. In addition, the continuous changes in eyeball abduction angle in response to varying stimulation intensity over time were observed.

Disrupted cognitive network revealed by task-induced brain entropy in schizophrenia.

Brain entropy (BEN), which measures the amount of information in brain activity, provides a novel perspective for evaluating brain function. Recent studies using resting-state functional magnetic resonance imaging (fMRI) have shown that BEN during rest can help characterize brain function alterations in schizophrenia (SCZ). However, there is a lack of research on BEN using task-evoked fMRI to explore task-dependent cognitive deficits in SCZ. In this study, we evaluate whether the reduced working memory (WM) capacity in SCZ is possibly associated with dynamic changes in task BEN during tasks with high cognitive demands. We analyzed data from 15 patients with SCZ and 15 healthy controls (HC), calculating task BEN from their N-back task fMRI scans. We then examined correlations between task BEN values, clinical symptoms, 2-back task performance, and neuropsychological test scores. Patients with SCZ exhibited significantly reduced task BEN in the cerebellum, hippocampus, parahippocampal gyrus, thalamus, and the middle and superior frontal gyrus (MFG and SFG) compared to HC. In HC, significant positive correlations were observed between task BEN and 2-back accuracy in several brain regions, including the MFG and SFG; such correlations were absent in patients with SCZ. Additionally, task BEN was negatively associated with scores for both positive and negative symptoms in areas including the parahippocampal gyrus among patients with SCZ. In conclusion, our findings indicate that a reduction in BEN within prefrontal and hippocampal regions during cognitively demanding tasks may serve as a neuroimaging marker for SCZ.

Multi-functional GdEuxTb1-xO3 (x = 0 to 1) nanoparticles: colour tuning optical properties, water proton spin relaxivities, and X-ray attenuation properties.

Multi-functional nanoparticles are useful for various applications, such as biomedical imaging, detection, and display technologies. Colour-tunable GdEuxTb1-xO3 nanoparticles were synthesized with emission colour ranging from green (545 nm) to red (616 nm) by varying x (x = 0, 0.1, 0.3, 0.5, 0.7, 0.9, and 1). These nanoparticles were surface-grafted with polyacrylic acid and a small quantity of 2,6-pyridinedicarboxylic acid. This modification aimed to ensure long-term colloidal stability (>1 year without precipitation) and high quantum yields (>30%) in aqueous media. Additionally, they exhibited long emission lifetimes (∼1 ms), high longitudinal water proton spin relaxivities (>30 s-1mM-1), and high X-ray attenuation efficiencies (∼10 HU mM-1). These multiple exceptional properties within a single nanoparticle make them highly valuable for applications in biomedical imaging, noise-free signal detection, and colour display.

Age-related alterations in human cortical microstructure across the lifespan: Insights from high-gradient diffusion MRI.

The human brain undergoes age-related microstructural alterations across the lifespan. Soma and Neurite Density Imaging (SANDI), a novel biophysical model of diffusion MRI, provides estimates of cell body (soma) radius and density, and neurite density in gray matter. The goal of this cross-sectional study was to assess the sensitivity of high-gradient diffusion MRI toward age-related alterations in cortical microstructure across the adult lifespan using SANDI. Seventy-two cognitively unimpaired healthy subjects (ages 19-85 years; 40 females) were scanned on the 3T Connectome MRI scanner with a maximum gradient strength of 300mT/m using a multi-shell diffusion MRI protocol incorporating 8 b-values and diffusion time of 19 ms. Intra-soma signal fraction obtained from SANDI model-fitting to the data was strongly correlated with age in all major cortical lobes (r = -0.69 to -0.60, FDR-p < 0.001). Intra-soma signal fraction (r = 0.48-0.63, FDR-p < 0.001) and soma radius (r = 0.28-0.40, FDR-p < 0.04) were significantly correlated with cortical volume in the prefrontal cortex, frontal, parietal, and temporal lobes. The strength of the relationship between SANDI metrics and age was greater than or comparable to the relationship between cortical volume and age across the cortical regions, particularly in the occipital lobe and anterior cingulate gyrus. In contrast to the SANDI metrics, all associations between diffusion tensor imaging (DTI) and diffusion kurtosis imaging metrics and age were low to moderate. These results suggest that high-gradient diffusion MRI may be more sensitive to underlying substrates of neurodegeneration in the aging brain than DTI and traditional macroscopic measures of neurodegeneration such as cortical volume and thickness.

Interplay between MRI-based axon diameter and myelination estimates in macaque and human brain.

Axon diameter and myelin thickness are closely related microstructural tissue properties that affect the conduction velocity of action potentials in the nervous system. Imaging them non-invasively with MRI-based methods is thus valuable for studying brain microstructure and function. However, the relationship between MRI-based axon diameter and myelination measures has not been investigated across the brain, mainly due to methodological limitations in estimating axon diameters. In recent years, studies using ultra-high gradient strength diffusion MRI (dMRI) have demonstrated improved estimation of axon diameter across white-matter (WM) tracts in the human brain, making such investigations feasible. In this study, we aim to investigate relationships between tissue microstructure properties with MRI-based methods and compare the imaging findings to histological evidence from the literature. We collected dMRI with ultra-high gradient strength and multi-echo spin-echo MRI on ex vivo macaque and human brain samples on a preclinical scanner. From these data, we estimated axon diameter, intra-axonal signal fraction, myelin water fraction (MWF) and aggregate g-ratio and investigated their correlations. We found that the microstructural imaging parameters exhibited consistent patterns across WM tracts and species. Overall, the findings suggest that MRI-based axon geometry and myelination measures can provide complementary information about fiber morphology, and the relationships between these measures agree with prior histological evidence.

Response surface methodology mediated optimization of phytosulfokine and plant growth regulators for enhanced protoplast division, callus induction, and somatic embryogenesis in Angelica Gigas Nakai.

BACKGROUND: Angelica Gigas (Purple parsnip) is an important medicinal plant that is cultivated and utilized in Korea, Japan, and China. It contains bioactive substances especially coumarins with anti-inflammatory, anti-platelet aggregation, anti-cancer, anti-diabetic, antimicrobial, anti-obesity, anti-oxidant, immunomodulatory, and neuroprotective properties. This medicinal crop can be genetically improved, and the metabolites can be obtained by embryonic stem cells. In this context, we established the protoplast-to-plant regeneration methodology in Angelica gigas. RESULTS: In the present investigation, we isolated the protoplast from the embryogenic callus by applying methods that we have developed earlier and established protoplast cultures using Murashige and Skoog (MS) liquid medium and by embedding the protoplast in thin alginate layer (TAL) methods. We supplemented the culture medium with growth regulators namely 2,4-dichlorophenoxyaceticacid (2,4-D, 0, 0.75, 1.5 mg L- 1), kinetin (KN, 0, 0.5, and 1.0 mg L- 1) and phytosulfokine (PSK, 0, 50, 100 nM) to induce protoplast division, microcolony formation, and embryogenic callus regeneration. We applied central composite design (CCD) and response surface methodology (RSM) for the optimization of 2,4-D, KN, and PSK levels during protoplast division, micro-callus formation, and induction of embryogenic callus stages. The results revealed that 0.04 mg L- 1 2,4-D + 0.5 mg L- 1 KN + 2 nM PSK, 0.5 mg L- 1 2,4-D + 0.9 mg L- 1 KN and 90 nM PSK, and 1.5 mg L- 1 2,4-D and 1 mg L- 1 KN were optimum for protoplast division, micro-callus formation and induction embryogenic callus. MS basal semi-solid medium without growth regulators was good for the development of embryos and plant regeneration. CONCLUSIONS: This study demonstrated successful protoplast culture, protoplast division, micro-callus formation, induction embryogenic callus, somatic embryogenesis, and plant regeneration in A. gigas. The methodologies developed here are quite useful for the genetic improvement of this important medicinal plant.

Intrinsic and extrinsic contributors to subregional thalamic volume loss in multiple sclerosis.

OBJECTIVE: To evaluate the intrinsic and extrinsic microstructural factors contributing to atrophy within individual thalamic subregions in multiple sclerosis using in vivo high-gradient diffusion MRI. METHODS: In this cross-sectional study, 41 people with multiple sclerosis and 34 age and sex-matched healthy controls underwent 3T MRI with up to 300 mT/m gradients using a multi-shell diffusion protocol consisting of eight b-values and diffusion time of 19 ms. Each thalamus was parcellated into 25 subregions for volume determination and diffusion metric estimation. The soma and neurite density imaging model was applied to obtain estimates of intra-neurite, intra-soma, and extra-cellular signal fractions for each subregion and within structurally connected white matter trajectories and cortex. RESULTS: Multiple sclerosis-related volume loss was more pronounced in posterior/medial subregions than anterior/ventral subregions. Intra-soma signal fraction was lower in multiple sclerosis, reflecting reduced cell body density, while the extra-cellular signal fraction was higher, reflecting greater extra-cellular space, both of which were observed more in posterior/medial subregions than anterior/ventral subregions. Lower intra-neurite signal fraction in connected normal-appearing white matter and lower intra-soma signal fraction of structurally connected cortex were associated with reduced subregional thalamic volumes. Intrinsic and extrinsic microstructural measures independently related to subregional volume with heterogeneity across atrophy-prone thalamic nuclei. Extrinsic microstructural alterations predicted left anteroventral, intrinsic microstructural alterations predicted bilateral medial pulvinar, and both intrinsic and extrinsic factors predicted lateral geniculate and medial mediodorsal volumes. INTERPRETATION: Our results might be reflective of the involvement of anterograde and retrograde degeneration from white matter demyelination and cerebrospinal fluid-mediated damage in subregional thalamic volume loss.

MLL1 histone methyltransferase and UTX histone demethylase functionally cooperate to regulate the expression of NRF2 in response to ROS-induced oxidative stress.

The transcription factor NRF2 plays a pivotal role in maintaining redox and metabolic homeostasis by orchestrating oxidative stress-dependent transcription programs. Despite growing evidence implicating various cellular components in the regulation of NRF2 activity at the posttranslational stage, relatively less is known about the factors dictating the transcriptional activation of NRF2 in response to oxidative stress. In this study, we report the crucial roles of MLL1, an H3K4-specific methyltransferase, and UTX, an H3K27-specific histone demethylase, in the NRF2-dependent transcription program under oxidative stress. We find that the depletion of MLL1 or UTX results in increased susceptibility to oxidative stress, accompanied by higher intracellular ROS and the failed activation of antioxidant genes, including NRF2. In addition, MLL1 and UTX selectively target the NRF2 promoter, and exogenous FLAG-NRF2 expression increases the viability of MLL1-or UTX-depleted cells upon exposure to hydrogen peroxide. RNA-seq analysis demonstrates that depletion of MLL1 or UTX affects the changes in NRF2-dependent transcriptome in response to oxidative stress. Furthermore, ChIP and ChIP-seq analyses find that MLL1 and UTX functionally cooperate to establish a chromatin environment that favors active transcription at the H3K4me3/H3K27me3 bivalent NRF2 promoter in response to ROS-induced oxidative stress. Collectively, these findings provide a molecular mechanism underlying the cellular response to oxidative stress and highlight the importance of the chromatin structure and function in maintaining redox homeostasis.

Enhanced selective discrimination of point-mutated viral RNA through false amplification regulatory direct insertion in rolling circle amplification.

Coronaviruses are single-stranded RNA viruses with high mutation rates. Although a diagnostic method for coronaviruses has been developed, variants appear rapidly. Low test accuracy owing to single-point mutations is one of the main factors in the failure to prevent the early spread of coronavirus infection. Although reverse transcription-quantitative polymerase chain reaction can detect coronavirus infection, it cannot exclude the possibility of false positives, and an additional multiplexing kit is needed to discriminate single nucleotide polymorphism (SNP) variants. Therefore, in this study, we introduced a new nucleic acid amplification method to determine whether an infected person has a SNP mutation using a lateral flow assay (LFA) as a point-of-care test. Unlike traditional DNA amplification methods, direct insertion into rolling circle amplification amplifies the target genes without false amplification. After SNP-selective nucleic acid amplification, nuclease enzymes are used to make double-stranded DNA fragments that the LFA can detect, where specific mismatched DNA is found and cleaved to show different signals when a SNP-type is present. Therefore, wild- and SNP-type variants can be selectively detected. In this study, the limit of detection was 400 aM for viral RNA, and we successfully identified a dominant SNP variant selectively. Clinical tests were also conducted.

Cryo-EM structures of human DICER dicing a pre-miRNA substrate.

Dicer, a multi-domain ribonuclease III (RNase III) protein, is crucial for gene regulation via RNA interference. It processes hairpin-like precursors into microRNAs (miRNAs) and long double-stranded RNAs (dsRNAs) into small interfering RNAs (siRNAs). During the "dicing" process, the miRNA or siRNA substrate is stably anchored and cleaved by Dicer's RNase III domain. Although numerous studies have investigated long dsRNA cleavage by Dicer, the specific mechanism by which human Dicer (hDICER) processes pre-miRNA remains unelucidated. This review introduces the recently revealed hDICER structure bound to pre-miRNA uncovered through cryo-electron microscopy and compares it with previous reports describing Dicer. The domain-wise movements of the helicase and dsRNA-binding domain (dsRBD) and specific residues involved in substrate sequence recognition have been identified. During RNA substrate binding, the hDICER apical domains and dsRBD recognize the pre-miRNA termini and cleavage site, respectively. Residue rearrangements in positively charged pockets within the apical domain influence substrate recognition and cleavage site determination. The specific interactions between dsRBD positively charged residues and nucleotide bases near the cleavage site emphasize the significance of cis-acting elements in the hDICER processing mechanism. These findings provide valuable insights for understanding hDICER-related diseases.

Automatic detection and classification of nasopalatine duct cyst and periapical cyst on panoramic radiographs using deep convolutional neural networks.

OBJECTIVE: The aim of this study was to evaluate a deep convolutional neural network (DCNN) method for the detection and classification of nasopalatine duct cysts (NPDC) and periapical cysts (PAC) on panoramic radiographs. STUDY DESIGN: A total of 1,209 panoramic radiographs with 606 NPDC and 603 PAC were labeled with a bounding box and divided into training, validation, and test sets with an 8:1:1 ratio. The networks used were EfficientDet-D3, Faster R-CNN, YOLO v5, RetinaNet, and SSD. Mean average precision (mAP) was used to assess performance. Sixty images with no lesion in the anterior maxilla were added to the previous test set and were tested on 2 dentists with no training in radiology (GP) and on EfficientDet-D3. The performances were comparatively examined. RESULTS: The mAP for each DCNN was EfficientDet-D3 93.8%, Faster R-CNN 90.8%, YOLO v5 89.5%, RetinaNet 79.4%, and SSD 60.9%. The classification performance of EfficientDet-D3 was higher than that of the GPs' with accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of 94.4%, 94.4%, 97.2%, 94.6%, and 97.2%, respectively. CONCLUSIONS: The proposed method achieved high performance for the detection and classification of NPDC and PAC compared with the GPs and presented promising prospects for clinical application.

Aberrant vascular architecture in the hippocampus correlates with tau burden in mild cognitive impairment and Alzheimer's disease.

Cerebrovascular dysfunction is a significant contributor to Alzheimer's disease (AD) progression. AD mouse models show altered capillary morphology, density, and diminished blood flow in areas of tau and beta-amyloid accumulation. The purpose of this study was to examine alterations in vascular structure and their contributions to perfusion deficits in the hippocampus in AD and mild cognitive impairment (MCI). Seven individuals with AD and MCI (1 AD/6 MCI), nine cognitively intact older healthy adults, and seven younger healthy adults underwent pseudo-continuous arterial spin labeling (PCASL) and gradient-echo/spin-echo (GESE) dynamic susceptibility contrast (DSC) MRI. Cerebral blood flow (CBF), cerebral blood volume, relative vessel size index (rVSI), and mean vessel density were calculated from model fitting. Lower CBF from PCASL and SE DSC MRI was observed in the hippocampus of AD/MCI group. rVSI in the hippocampus of the AD/MCI group was larger than that of the two healthy groups (FDR-P = 0.02). No difference in vessel density was detected between the groups. We also explored relationship of tau burden from 18F-flortaucipir positron emission tomography and vascular measures from MRI. Tau burden was associated with larger vessel size and lower CBF in the hippocampus. We postulate that larger vessel size may be associated with vascular alterations in AD/MCI.

Comparative analysis of infertility healthcare utilization before and after insurance coverage of assisted reproductive technology: A cross-sectional study using National Patient Sample data.

This study aims to analyze the types and cost of infertility care provided in a clinical setting to examine the changes of healthcare utilization for infertility after the 2017 launch of assisted reproductive technology (ART) health insurance coverage in South Korea. Health Insurance Review Assessment-National Patient Sample data from 2016 and 2018 were analyzed comparatively. Data related to receiving medical service under the International Classification of Diseases 10th revision code N97 (female infertility) or N46 (male infertility) at least once were analyzed, including patients' characteristics and healthcare utilization (type of healthcare facility and treatment approach). Between 2016 and 2018, the percentage of patients aged 30-34 receiving infertility care dropped; the percentages of patients in older age groups increased. The number of female patients remained comparable, whereas the number of male patients increased by 23%. Average visits per patient increased by about 1 day from 2016 to 2018. Total annual infertility care claim cost increased from $665,391.05 to $3,214,219.48; the per-patient annual cost increased from $114.76 to $522.38. The number of claims and cost of treatment and surgery increased markedly, as did the number of claims and cost of gonadotropins. With its focus on health insurance coverage of ART and results demonstrating increases in medical services, medications, cost, and patient utilization, this study reveals the significant effects of national health policies on the treatment, cost, and management of infertility.

Suspension culture of somatic embryos for the production of high-value secondary metabolites.

Secondary metabolites from plants are ubiquitous and have applications in medicines, food additives, scents, colorants, and natural pesticides. Biotechnological production of secondary metabolites that have economic benefits is an attractive alternative to conventional methods. Cell, adventitious, and hairy root suspension cultures are typically used to produce secondary metabolites. According to recent studies, somatic embryos in suspension culture are useful tools for the generation of secondary metabolites. Somatic embryogenesis is a mode of regeneration in several plant species. This review provides an update on the use of somatic embryogenesis in the production of valuable secondary metabolites. The factors influencing the generation of secondary metabolites using somatic embryos in suspension cultures, elicitation methods, and prospective applications are also discussed in this review.

GuaRD: Guaranteed robustness of image retrieval system under data distortion turbulence.

Image search systems could be endangered by adversarial attacks and data perturbations. The image retrieval system can be compromised either by distorting the query or hacking the ranking system. However, existing literature primarily discusses attack methods, whereas the research on countermeasures to defend against such adversarial attacks is rare. As a defense mechanism against the intrusions, quality assessment can complement existing image retrieval systems. "GuaRD" is proposed as an end-to-end framework that uses the quality metric as a weighted-regularization term. Proper utilization and balance of the two features could lead to reliable and robust ranking; the original image is assigned a higher rank while the distorted image is assigned a relatively lower rank. Meanwhile, the primary goal of the image retrieval system is to prioritize searching the relevant images. Therefore, the use of leveraged features should not compromise the accuracy of the system. To evaluate the generality of the framework, we conducted three experiments on two image quality assessment(IQA) benchmarks (Waterloo and PieAPP). For the first two tests, GuaRD achieved enhanced performance than the existing model: the mean reciprocal rank(mRR) value of the original image predictions increased by 61%, and the predictions for the distorted input query decreased by 18%. The third experiment was conducted to analyze the mean average precision (mAP) score of the system to verify the accuracy of the retrieval system. The results indicated little deviation in performance between the tested methods, and the score was not effected or slightly decreased by 0.9% after the GuaRD was applied. Therefore, GuaRD is a novel and robust framework that can act as a defense mechanism for data distortions.

Quantifying the Viscosity of Individual Submicrometer Semisolid Particles Using Atomic Force Microscopy.

Atmospheric aerosols' viscosities can vary significantly depending on their composition, mixing states, relative humidity (RH) and temperature. The diffusion time scale of atmospheric gases into an aerosol is largely governed by its viscosity, which in turn influences heterogeneous chemistry and climate-relevant aerosol effects. Quantifying the viscosity of aerosols in the semisolid phase state is particularly important as they are prevalent in the atmosphere and have a wide range of viscosities. Currently, direct viscosity measurements of submicrometer individual atmospheric aerosols are limited, largely due to the inherent size limitations of existing experimental techniques. Herein, we present a method that utilizes atomic force microscopy (AFM) to directly quantify the viscosity of substrate-deposited individual submicrometer semisolid aerosol particles as a function of RH. The method is based on AFM force spectroscopy measurements coupled with the Kelvin-Voigt viscoelastic model. Using glucose, sucrose, and raffinose as model systems, we demonstrate the accuracy of the AFM method within the viscosity range of ∼104-107 Pa s. The method is applicable to individual particles with sizes ranging from tens of nanometers to several micrometers. Furthermore, the method does not require prior knowledge on the composition of studied particles. We anticipate future measurements utilizing the AFM method on atmospheric aerosols at various RH to aid in our understanding of the range of aerosols' viscosities, the extent of particle-to-particle viscosity variability, and how these contribute to the particle diversity observable in the atmosphere.

NFIB-MLL1 complex is required for the stemness and Dlx5-dependent osteogenic differentiation of C3H10T1/2 mesenchymal stem cells.

Despite significant progress in our understanding of the molecular mechanism of mesenchymal stem cell (MSC) differentiation, less is known about the factors maintaining the stemness and plasticity of MSCs. Here, we show that the NFIB-MLL1 complex plays key roles in osteogenic differentiation and stemness of C3H10T1/2 MSCs. We find that depletion of either NFIB or MLL1 results in a severely hampered osteogenic potential and failed activation of key osteogenic transcription factors, such as Dlx5, Runx2, and Osx, following osteogenic stimuli. In addition, the NFIB-MLL1 complex binds directly to the promoter of Dlx5, and exogenous expression of Myc-Dlx5, but not the activation of either the BMP- or the Wnt-signaling pathway, is sufficient to restore the osteogenic potential of cells depleted of NFIB or MLL1. Moreover, chromatin immunoprecipitation (ChIP) and ChIP-sequencing analysis showed that the NFIB-MLL1 complex mediates the deposition of trimethylated histone H3K4 at both Dlx5 and Cebpa, key regulator genes that function at the early stages of osteogenic and adipogenic differentiation, respectively, in uncommitted C3H10T1/2 MSCs. Surprisingly, the depletion of either NFIB or MLL1 leads to decreased trimethylated histone H3K4 and results in elevated trimethylated histone H3K9 at those developmental genes. Furthermore, gene expression profiling and ChIP-sequencing analysis revealed lineage-specific changes in chromatin landscape and gene expression in response to osteogenic stimuli. Taken together, these data provide evidence for the hitherto unknown role of the NFIB-MLL1 complex in the maintenance and lineage-specific differentiation of C3H10T1/2 MSCs and support the epigenetic regulatory mechanism underlying the stemness and plasticity of MSCs.

Diagnostic performance of respirators for collection and detection of SARS-CoV-2.

Respirators, called as face mask, have been used to protect the wearer from the outside harmful air environment and prevent any virus from being released to neighbors from potentially infected exhaled breath. The antiviral effectiveness of respirators has not only been researched scientifically, but has also become a global issue due to society's obligation to wear respirators. In this paper, we report the results of a study on the collection and detection of viruses contained in exhaled breath using respirators. The inner electrostatic filter was carefully selected for virus collection because it does not come in direct contact with either human skin or the external environment. In the study of a healthy control group, it was confirmed that a large amount of DNA and biomolecules such as exosomes were collected from the respirator exposed to exhalation, and the amount of collection increased in proportion to the wearing time. We conducted experiments using a total of 72 paired samples with nasopharyngeal swabs and respirator samples. Out of these samples, fifty tested positive for SARS-CoV-2 and twenty-two tested negative. The PCR results of the NPS and respirator samples showed a high level of agreement, with a positive percent agreement of ≥ 90% and a negative percent agreement of ≥ 99%. Furthermore, there was a notable level of concordance between RCA-flow tests and PCR when examining the respirator samples. These results suggest that this is a non-invasive, quick and easy method of collecting samples from subjects using a respirator, which can significantly reduce the hassle of waiting at airports or public places and concerns about cross-contamination. Furthermore, we expect miniaturized technologies to integrate PCR detection into respirators in the near future.

Copper Oxide Spike Grids for Enhanced Solution Transfer in Cryogenic Electron Microscopy.

The formation of uniform vitreous ice is a crucial step in the preparation of samples for cryogenic electron microscopy (cryo-EM). Despite the rapid technological progress in EM, controlling the thickness of vitreous ice on sample grids with reproducibility remains a major obstacle to obtaining high-quality data in cryo-EM imaging. The commonly employed classical blotting process faces the problem of excess water that cannot be absorbed by the filter paper, resulting in the formation of thick and heterogeneous ice. In this study, we propose a novel approach that combines the recently developed nanowire self-wicking technique with the classical blotting method to effectively control the thickness and homogeneity of vitrified ice. With simple procedures, we generated a copper oxide spike (COS) grid by inducing COSs on commercially available copper grids, which can effectively remove excess water during the blotting procedure without damaging the holey carbon membrane. The ice thickness could be controlled with good reproducibility compared to non-oxidized grids. Incorporated into other EM techniques, our new modification method is an effective option for obtaining high-quality data during cryo-EM imaging.