A Zinc Finger Motif in the P1 N Terminus, Highly Conserved in a Subset of Potyviruses, Is Associated with the Host Range and Fitness of Telosma Mosaic Virus

P1 is the first protein translated from the genomes of most viruses in the family Potyviridae, and it contains a C-terminal serine-protease domain that cis-cleaves the junction between P1 and HCPro in most cases. Intriguingly, P1 is the most divergent among all mature viral factors, and its roles during viral infection are still far from understood. In this study, we found that telosma mosaic virus (TelMV, genus Potyvirus) in passion fruit, unlike TelMV isolates present in other hosts, has two stretches at the P1 N terminus, named N1 and N2, with N1 harboring a Zn finger motif. Further analysis revealed that at least 14 different potyviruses, mostly belonging to the bean common mosaic virus subgroup, encode a domain equivalent to N1. Using the newly developed TelMV infectious cDNA clones from passion fruit, we demonstrated that N1, but not N2, is crucial for viral infection in both Nicotiana benthamiana and passion fruit. The regulatory effects of N1 domain on P1 cis cleavage, as well as the accumulation and RNA silencing suppression (RSS) activity of its cognate HCPro, were comprehensively investigated. We found that N1 deletion decreases HCPro abundance at the posttranslational level, likely by impairing P1 cis cleavage, thus reducing HCPro-mediated RSS activity. Remarkably, disruption of the Zn finger motif in N1 did not impair P1 cis cleavage and HCPro accumulation but severely debilitated TelMV fitness. Therefore, our results suggest that the Zn finger motif in P1s plays a critical role in viral infection that is independent of P1 protease activity and self-release, as well as HCPro accumulation and silencing suppression.This work is supported by grants from the Hainan Provincial National Science Foundation (grant nos. 2019RC010 and 322CXTD505), Sanya Yazhou Bay Sci-Tech City (SYND-2022-32 and SYND-2022-02), the National Natural Science Foundation of China (32060603), and the Central Public Interest Scientific Institution Basal Research Fund for Chinese Academy of Tropical Agricultural Sciences (19CXTD-33). We thank Fangfang Li (Chinese Academy of Agricultural Sciences) for providing pCHF3-35S-GFP and P19-expressing plasmidPeer reviewe

Solenoid-free current drive via ECRH in EXL-50 spherical torus plasmas

As a new spherical tokamak (ST) designed to simplify engineering requirements of a possible future fusion power source, the EXL-50 experiment features a low aspect ratio (A) vacuum vessel (VV), encircling a central post assembly containing the toroidal field coil conductors without a central solenoid. Multiple electron cyclotron resonance heating (ECRH) resonances are located within the VV to improve current drive effectiveness. Copious energetic electrons are produced and measured with hard X-ray detectors, carry the bulk of the plasma current ranging from 50kA to 150kA, which is maintained for more than 1s duration. It is observed that over one Ampere current can be maintained per Watt of ECRH power issued from the 28-GHz gyrotrons. The plasma current reaches Ip>80kA for high density (>5e18me-2) discharge with 150kW ECHR heating. An analysis was carried out combining reconstructed multi-fluid equilibrium, guiding-center orbits of energetic electrons, and resonant heating mechanisms. It is verified that in EXL-50 a broadly distributed current of energetic electrons creates smaller closed magnetic-flux surfaces of low aspect ratio that in turn confine the thermal plasma electrons and ions and participate in maintaining the equilibrium force-balance

Generating Aptamers by Cell-SELEX for Applications in Molecular Medicine

Aptamers are single-stranded oligonucleotides of DNA or RNA that bind to target molecules with high affinity and specificity. Typically, aptamers are generated by an iterative selection process, called systematic evolution of ligands by exponential enrichment (SELEX). Recent advancements in SELEX technology have extended aptamer selection from comparatively simple mixtures of purified proteins to whole living cells, and now cell-based SELEX (or cell-SELEX) can isolate aptamers that bind to specific target cells. Combined with nanotechnology, microchips, microfluidic devices, RNAi and other advanced technologies, cell-SELEX represents an integrated platform providing ultrasensitive and highly specific tools for clinical medicine. In this review, we describe the recent progress made in the application of cell-SELEX for diagnosis, therapy and biomarker discovery

Engineering Properties and Microscopic Mechanisms of Composite-Cemented Soil as Backfill of Ultra-Deep and Ultra-Narrow Foundation Trenches

The backfilling of lime soil in ultra-deep and ultra-narrow foundation trenches is a difficult construction link, and ordinary-cemented soil has drawbacks, including poor strength, impermeability, and frost resistance. To solve these problems, fly ash (FA)–water glass (WG)-composite-cemented soil is developed based on a background project. The three-factor orthogonal tests are conducted on the unconfined compressive strength (UCS) of the composite-cemented soil, and the optimal engineering mix proportion is proposed for the FA-WG-composite-cemented soil. Its UCS is compared with that of cemented soil only doped with FA or WG (FA- and WG-cemented soil). In addition, the cyclic wetting–drying tests, cyclic freeze–thaw tests, and impermeability tests are carried out to study the endurance of the composite-cemented soil in cold regions rich in water. The hydration products of the composite-cemented soil are investigated through scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis, and the curing mechanism of the composite-cemented soil is discussed from the microscopic perspective. The research results indicate that the mixing ratio of cement is crucial to the strength development of the cemented soil; the mixing ratio of FA greatly influences the strength development of the cemented soil in the middle and late stages; the mixing ratio of WG only slightly affects the strength. The ratio of cement, FA, and WG of 9%:12%:3% is the optimal engineering mix proportion of the composite-cemented soil. Compared with ordinary-cemented oil and FA- and WG-cemented soil, the composite-cemented soil shows significantly improved compressive load-bearing capacity. The permeability coefficient of the composite-cemented soil is always obviously lower than that of the ordinary-cemented soil after any curing period. Despite the mass loss, the composite-cemented soil is superior to the ordinary one in overall endurance after wetting–drying and freeze–thaw cycles. Through SEM and XRD analysis, the content of hydration products of the composite-cemented soil is found to be obviously higher than that of ordinary-cemented soil after any curing period, and the hydrates exert stronger cementing action on soil particles in the composite-cemented soil. The contents of C-S-H gel and Aft crystals in the composite-cemented soil are apparently larger than those in the ordinary-cemented soil. Under the alkali activation of WG, the FA produces free SiO32− and AlO2−, which undergo the polymerization reaction with Ca2+ to generate C-S-H gel and C-A-H gel, further promoting the hydration of cement

Engineering Properties and Microscopic Mechanisms of Composite-Cemented Soil as Backfill of Ultra-Deep and Ultra-Narrow Foundation Trenches

The backfilling of lime soil in ultra-deep and ultra-narrow foundation trenches is a difficult construction link, and ordinary-cemented soil has drawbacks, including poor strength, impermeability, and frost resistance. To solve these problems, fly ash (FA)–water glass (WG)-composite-cemented soil is developed based on a background project. The three-factor orthogonal tests are conducted on the unconfined compressive strength (UCS) of the composite-cemented soil, and the optimal engineering mix proportion is proposed for the FA-WG-composite-cemented soil. Its UCS is compared with that of cemented soil only doped with FA or WG (FA- and WG-cemented soil). In addition, the cyclic wetting–drying tests, cyclic freeze–thaw tests, and impermeability tests are carried out to study the endurance of the composite-cemented soil in cold regions rich in water. The hydration products of the composite-cemented soil are investigated through scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis, and the curing mechanism of the composite-cemented soil is discussed from the microscopic perspective. The research results indicate that the mixing ratio of cement is crucial to the strength development of the cemented soil; the mixing ratio of FA greatly influences the strength development of the cemented soil in the middle and late stages; the mixing ratio of WG only slightly affects the strength. The ratio of cement, FA, and WG of 9%:12%:3% is the optimal engineering mix proportion of the composite-cemented soil. Compared with ordinary-cemented oil and FA- and WG-cemented soil, the composite-cemented soil shows significantly improved compressive load-bearing capacity. The permeability coefficient of the composite-cemented soil is always obviously lower than that of the ordinary-cemented soil after any curing period. Despite the mass loss, the composite-cemented soil is superior to the ordinary one in overall endurance after wetting–drying and freeze–thaw cycles. Through SEM and XRD analysis, the content of hydration products of the composite-cemented soil is found to be obviously higher than that of ordinary-cemented soil after any curing period, and the hydrates exert stronger cementing action on soil particles in the composite-cemented soil. The contents of C-S-H gel and Aft crystals in the composite-cemented soil are apparently larger than those in the ordinary-cemented soil. Under the alkali activation of WG, the FA produces free SiO32− and AlO2−, which undergo the polymerization reaction with Ca2+ to generate C-S-H gel and C-A-H gel, further promoting the hydration of cement

High luminous fluorescence generation using Ce:YAG transparent ceramic excited by blue laser diode

Solid-state laser lighting is an emerging technology, whereby high-brightness white light can be generated using blue laser diodes combined with a yellow-emitting phosphor. In this study, Ce:YAG transparent ceramic wafers with different cerium concentrations and thicknesses are prepared and their optical characteristics are measured. A transmission mode is used, wherein the phosphor ceramic is fixed onto an oxygen-free copper sink, whose temperature is accurately controlled, and excited using the blue laser diode. The recorded spectrum shows that blue laser light is completely converted to yellow light with a wavelength of 565 nm and width of 200 nm. Moreover, with varied temperatures of 10-80 degrees C, the luminous flux, spectrum, and color coordinates exhibit relatively stable. More importantly, the luminous flux is highest (2690 lm) when irradiated by a 19.5-W blue laser (with a center wavelength of 454 nm) for a Ce3+ dopant concentration of 0.5 mol% and a Ce:YAG thickness of 1.6 mm. Based on these results, the Ce:YAG transparent ceramic can be used as a potential phosphor material in applications of high-power solid-state laser lighting and laser display. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Single-Crystalline Germanium Nanocrystals via a Two-Step Microwave-Assisted Colloidal Synthesis from GeI4.

Colloidal germanium (Ge) nanocrystals (NCs) are of great interest with possible applications for photovoltaics and near-IR detectors. In many examples of colloidal reactions, Ge(II) precursors are employed, and NCs of diameter ∼3-10 nm have been prepared. Herein, we employed a two-step microwave-assisted reduction of GeI4 in oleylamine (OAm) to prepare monodispersed Ge NCs with a size of 18.9 ± 1.84 nm. More importantly, the as-synthesized Ge NCs showed high crystallinity with single-crystal nature as indicated by powder X-ray diffraction, selected area electron diffraction, and high-resolution transmission electron microscopy. The Tauc plot derived from photothermal deflection spectroscopy measurement on Ge NCs thin films shows a decreased bandgap of the Ge NCs obtained from GeI4 compared with that of the Ge NCs from GeI2 with a similar particle size, indicating a higher crystallinity of the samples prepared with the two-step reaction from GeI4. The calculated Urbach energy indicates less disorder in the larger NCs. This disorder might correlate with the fraction of surface states associated with decreased particle size or with the increased molar ratio of ligands to germanium. Solutions involved in this two-step reaction were investigated with 1H NMR spectroscopy and high-resolution mass spectrometry (MS). One possible reaction pathway is proposed to unveil the details of the reaction involving GeI4 and OAm. Overall, this two-step synthesis produces high-quality Ge NCs and provides new insight on nanoparticle synthesis of covalently bonding semiconductors

High-Performance Holographic Photopolymers Based on Low Refractive Index Host Matrices Containing Fluoroelastomers

The refractive index modulation (Δn) of photopolymers is a key performance indicator in determining their application potentials in holographic optical elements (HOEs). In this study, four fluoroelastomers (HT-HS, HT-F185, HT-L80, and HT-F197) containing hydroxyl groups as active functional groups are selected to construct low refractive index host matrices with isocyanates. Through a combination of them with high refractive index monomers, a series of transparent photopolymers are obtained. Among them, one containing 16 wt % HT-F197 has the highest sensitivity, which can record a transmission volume holographic grating (VHG) with high resolution (3600 lines/mm) and diffraction efficiency (95.76%) under exposure of a 532 nm laser. Its Δn is up to 0.054. Furthermore, a reflection VHG with high performance (4900 lines/mm resolution and 92.32% diffraction efficiency) can also be achieved. After photobleaching, its transmittance within 400–800 nm reaches 96.21%, showing great potential in the fabrication of transparent HOEs

Hsa_Circ_0001275: A Potential Novel Diagnostic Biomarker for Postmenopausal Osteoporosis

Background/Aims: Circular RNAs (circRNAs) serve as potential diagnostic biomarkers. In this study, we aimed to identify a potential biomarker from peripheral blood mononuclear cells (PBMCs) of patients with postmenopausal osteoporosis (PMOP). Methods: CircRNA expression in PBMCs from three pairs of samples from PMOP patients and controls was initially detected by circRNA microarray. The changes in selected circRNAs in PBMCs from 28 PMOP patients and 21 age- and sex-matched controls were confirmed using quantitative reverse transcription polymerase chain reaction (qRT-PCR). Next, samples from 30 PMOP patients and 20 controls were used for further verification. Pearson correlation test was performed to assess the correlation between circRNAs and clinical variables. The area under the receiver operator characteristic (ROC) curve was calculated to evaluate the diagnostic value. Results: Six differentially expressed circRNAs were identified by chip microarray analysis, of which only hsa_circ_0001275 showed consistency and statistical significance in qRT-PCR. The correlation analysis between age, body weight, height, WBC, lymphocyte and monocyte count, bone density, T-score, β-CROSSL, OSTEOC, and TP1NP showed that hsa_circ_0001275 was negatively correlated with T-score. ROC curves showed that hsa_circ_0001275 has significant diagnostic value in PMOP (AUC=0.759, P< 0.001). Conclusion: This study suggests that hsa_circ_0001275 may serve as a potential diagnostic biomarker for PMOP