Transformation media that turn a narrow slit into a large window

Based on the transformation media theory, the authors propose a way to replace a wide window with a narrow slit filled with designed metamaterial to achieve the same transmittance as the one of the window. Numerical simulations for a two dimensional case are given to illustrate the ideas and the performance of the design.Comment: 10 pages, 3 figure

Establishment of an Inducible HBV Stable Cell Line that Expresses cccDNA-dependent Epitope-tagged HBeAg for Screening of cccDNA Modulators

Hepatitis B virus (HBV) covalently closed circular (ccc) DNA is essential to the virus life cycle, its elimination during chronic infection is considered critical to a durable therapy but has not been achieved by current antivirals. Despite being essential, cccDNA has not been the major target of high throughput screening (HTS), largely because of the limitations of current HBV tissue culture systems, including the impracticality of detecting cccDNA itself. In response to this need, we have previously developed a proof-of-concept HepDE19 cell line in which the production of wildtype e antigen (HBeAg) is dependent upon cccDNA. However, the existing assay system is not ideal for HTS because the HBeAg ELISA cross reacts with a viral HBeAg homologue, which is the core antigen (HBcAg) expressed largely in a cccDNA-independent fashion in HepDE19 cells. To further improve the assay specificity, we report herein a “second-generation” cccDNA reporter cell line, termed HepBHAe82. In the similar principle of HepDE19 line, an in-frame HA epitope tag was introduced into the precore domain of HBeAg open reading frame in the transgene of HepBHAe82 cells without disrupting any cis-element critical for HBV replication and HBeAg secretion. A chemiluminescence ELISA assay (CLIA) for the detection of HA-tagged HBeAg with HA antibody serving as capture antibody and HBeAb serving as detection antibody has been developed to eliminate the confounding signal from HBcAg. The miniaturized HepBHAe82 cell based assay system exhibits high level of cccDNA-dependent HA-HBeAg production and high specific readout signals with low background. We have also established a HepHA-HBe4 cell line expressing transgene-dependent HA-HBeAg as a counter screen to identify HBeAg inhibitors. The HepBHAe82 system is amenable to antiviral HTS development, and can be used to identify host factors that regulate cccDNA metabolism and transcription

Cooperativity among Short Amyloid Stretches in Long Amyloidogenic Sequences

Amyloid fibrillar aggregates of polypeptides are associated with many neurodegenerative diseases. Short peptide segments in protein sequences may trigger aggregation. Identifying these stretches and examining their behavior in longer protein segments is critical for understanding these diseases and obtaining potential therapies. In this study, we combined machine learning and structure-based energy evaluation to examine and predict amyloidogenic segments. Our feature selection method discovered that windows consisting of long amino acid segments of ∼30 residues, instead of the commonly used short hexapeptides, provided the highest accuracy. Weighted contributions of an amino acid at each position in a 27 residue window revealed three cooperative regions of short stretch, resemble the β-strand-turn-β-strand motif in A-βpeptide amyloid and β-solenoid structure of HET-s(218–289) prion (C). Using an in-house energy evaluation algorithm, the interaction energy between two short stretches in long segment is computed and incorporated as an additional feature. The algorithm successfully predicted and classified amyloid segments with an overall accuracy of 75%. Our study revealed that genome-wide amyloid segments are not only dependent on short high propensity stretches, but also on nearby residues

A systematic review of parental burnout and related factors among parents

Abstract Background Parenting is both a complex and stressful endeavor, so parents sometimes experience parenting burnout. The main objective of this study was to provide an overview of factors related to general parental burnout (PB) among parents with at least one child based on the Ecological Systems Theory (EST). Methods PubMed, Web of Science, EBSCO, CNKI and WanFang were systematically searched for studies published from 2010 to July 2023 for peer-reviewed articles using keywords extracted from Medical Subject Headings such as “parenting”, “parental”, “burnout”, “psychological burnout”, “burn-out syndrome”. Studies were included if they described associations between factors and PB among parents of children aged 0-18 years old in the general population, and published in an English or Chinese language peer-reviewed journal. The Quality Assessment Tool for Studies with Diverse Designs (QATSDD) was employed to assess the risk of bias of included studies. Results Of 2037 articles, 26 articles met the inclusion criteria. Based on the Ecological Systems Theory (EST), we found that microsystem-individual factors such as gender, educational level, income, parental personality, internalization of maternal parental motivation, unmitigated communion, self-compassion and concern for others, alexithymia, anxiety and depressive symptoms, parental perfectionism, resilience, low self-esteem and high need for control, mother's attachment style were identified as being associated with parenting burnout. Mesosystem-interpersonal factors involve parent-child relationship and marital satisfaction. The exosystem-organizational or community factors include the number of children in the household, neighborhood and the number of hours spent with children, child's illness, child's behavior problems and social support. The macrosystem-society/policy or culture factors are mainly personal values and cultural values. Conclusions This systematic review found several factors that have been investigated in relation to PB. However, the majority of the factors were reported by one or two studies often implementing a cross-sectional design. Nevertheless, we still recommend that health policymakers and administrators relieve parenting burnout among parents with children by adjusting these modifiable factors

Experimental Study on Engineering Characteristics of High-Speed Railway Subgrade Filler in Island Permafrost Regions

The high-speed railway (HSR) subgrade has a strict settlement-control standard at the mm level, but its deformation stability is significantly threatened on permafrost with poor thermal stability and in susceptible-to-thawing settlements. Therefore, the filler suitable for permafrost regions needs to be explored and determined. In this study, the frost heaves, permeabilities and static strength characteristics of three coarse fillers were experimentally investigated, and the optimal subgrade filler was determined for the certain HSR, the first HSR in permafrost regions around the world. The test fillers include pure fillers, 5% cement improved fillers and 5% cement + 3% modifier improved fillers, and the effects of curing time, modifier content and freeze–thaw cycles were analyzed. The test results show that: (1) the frost heave rate and permeability coefficient decrease with the increase of curing time and modifier content, while increasing with the freeze-thaw cycles; (2) After six freeze–thaw cycles, the cement + modifier improved filler’s frost heave rate and permeability coefficient are 0.51 and 0.00331 cm/s, a larger decrease in the frost heave rate (more than 50%) and the permeability coefficient (about one order of magnitude) than that of pure filler; (3) The cement + modifier improved filler shares the highest compressive strength under different curing times and freeze-thaw cycles. In summary, the modifier has a more significant influence on the engineering characteristics than the curing time or freeze-thaw cycles, and the cement + modifier improved filler has the best comprehensive performance. This study will provide a technical reference for the foundation-treatment and disease-prevention of HSRs in island permafrost regions

Estimating foliar anthocyanin content of purple corn via hyperspectral model

To date, the foliar anthocyanin content was either determined via the pH differential or HPLC methods, both of which are slow and destructive. Here, a hyperspectral model was established to estimate the foliar anthocyanin content of purple corn (Zea mays L. var. Jingzi No. 1). The reflectivity (P) of the foliar hyperspectral was inverted to 1/P, lg P, 1/lg P, urn:x-wiley:20487177:media:fsn3588:fsn3588-math-0001, urn:x-wiley:20487177:media:fsn3588:fsn3588-math-0002, urn:x-wiley:20487177:media:fsn3588:fsn3588-math-0003, and urn:x-wiley:20487177:media:fsn3588:fsn3588-math-0004. The correlation coefficient between these inversions and the foliar anthocyanin content was plotted against the hyperspectral wavelength. The wavelength of inversions around 650 nm was sensitive to the foliar anthocyanin content. The hyperspectral model was fitted via linear, polynomial, power, exponential, and logarithmic functions with the sensitive band as independent variable and the anthocyanin content as function. The hyperspectral model (y = 3,000,000,000 × W6854.5896) fitted via inversion of urn:x-wiley:20487177:media:fsn3588:fsn3588-math-0005 showed the highest determination coefficients (0.768) among all models. The hyperspectral model was well validated with a determination coefficient of 0.932 and an RMSE of 0.0065. Moreover, the accuracy and stability of the hyperspectral model were further enhanced with a determination coefficient of 0.954 and RMSE of 0.0047 when the anthocyanin content of the sample was below 20 mg/g. Hence, the hyperspectral model estimated the foliar anthocyanin content of purple corn quickly and nondestructively