We experimentally demonstrate the lasing action of electrically pumped octagonal quasi-crystal microcavities formed in a layer of conjugated polymer poly[2-methoxy- 5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) sandwiched between two electrodes. Lasing from a point-defect microcavity is observed at a wavelength of 606 nm with a narrow linewidth of 0.5 nm, limited by the spectrometer resolution. Due to the properties of the photonic bandgap and localization in photonic crystals, the threshold current for lasing is low at 0.8 mA. The ion injection in the luminescent polymer layer by focused ion beam (FIB) etching technology also contributes to enhancement of the carrier density as well as the mobility, resulting in an increase of MEH-PPV conductivity and a decrease of turn-on voltage.
Abstract Star‐like amphiphilic triblock copolymers were rationally designed and synthesized by combining two sequential atom‐transfer radical polymerization reactions with a click reaction. Subsequently, a family of uniform magnetic/plasmonic core/shell nanoparticles was crafted by capitalizing on these triblock copolymers as nanoreactors. The diameter of the magnetic core and the thickness of the plasmonic shell could be independently and accurately controlled by varying the molecular weights (i.e., the chain lengths) of the inner and intermediate blocks of the star‐like triblock copolymers, respectively. The surface plasmonic absorption of core/shell nanoparticles with different core diameters and shell thicknesses was systematically studied and theoretically modeled. This robust strategy provides easy access to a large variety of multifunctional nanoparticles with large lattice mismatches for use in optics, optoelectronics, catalysis, or bioimaging.
Virus propagation methods generally use transformed cell lines to grow viruses from clinical specimens, which may force viruses to rapidly adapt to cell culture conditions, a process facilitated by high viral mutation rates. Upon propagation in VeroE6 cells, SARS-CoV-2 may mutate or delete the multibasic cleavage site (MBCS) in the spike protein. Previously, we showed that the MBCS facilitates serine protease-mediated entry into human airway cells (Mykytyn et al., 2021). Here, we report that propagating SARS-CoV-2 on the human airway cell line Calu-3 – that expresses serine proteases – prevents cell culture adaptations in the MBCS and directly adjacent to the MBCS (S686G). Similar results were obtained using a human airway organoid-based culture system for SARS-CoV-2 propagation. Thus, in-depth knowledge on the biology of a virus can be used to establish methods to prevent cell culture adaptation.
BACKGROUND:This study evaluated the effects of Modified Yanghe Decoction on pain, disease activity, and functional capacity, and its safety in subjects with ankylosing spondylitis (AS). MATERIAL AND METHODS:A randomized, controlled study of subjects with AS was conducted over 8 weeks to compare the efficacy of the Modified Yanghe Decoction to celecoxib-sulfasalazine therapy. Subjects were evaluated at visit 1, and at weeks 4 and 8 of the trial. The Bath ankylosing spondylitis disease activity index (BASDAI), nocturnal back pain (NBP), total back pain (TBP), patient global disease activity (PGDA), the Bath ankylosing spondylitis functional index (BASFI), and the Bath ankylosing spondylitis metrology index (BASMI) were measured at each time point. Safety was monitored throughout the study through blood, urine, and stool samples, along with heart, liver, and kidney function tests. The ASAS 20 improvement criteria were used as efficacy criteria. RESULTS:A total of 80 subjects were included. Both treatment groups were effective: 32 subjects (80%) in the Modified Yanghe Decoction group and 34 (85%) in celecoxib-sulfasalazine group met ASAS 20 improvement criteria; no statistically significant difference between groups was observed (P>0.05). Two subjects in the Modified Yanghe Decoction group reported mild diarrhea during the trial. In the celecoxib-sulfasalazine group, 8 subjects experienced upper-abdominal pain; in 3 subjects this was combined with lowered white blood cell count and in 1 subject it was combined with mild proteinuria. This represents a statistically significant difference in safety (P<0.05) between the 2 treatments. CONCLUSIONS:This study demonstrates the efficacy and safety of the Modified Yanghe Decoction in AS treatment, especially for patients who have poor clinical responses, severe adverse reactions, or for patients unable to afford the standard clinical options.
We experimentally demonstrate and characterize an organic octagonal quasicrystal slab with a single-defect microcavity at low-index contrast. The gain medium is the conjugated-polymer, composed by two PPV derivatives, a BEHP-PPV and a MEH-PPV. By optical pumping, the lasing action is achieved at 607 nm with a FWHM of 1nm. The threshold of lasing is 9uJ/cm2. The intensity of the lasing peak depends linearly on the pump energy above the threshold.
An optically pumped two-dimensional organic quasi-crystal microcavity laser is demonstrated based on conjugated polymer poly(2-methoxy, 5-(2'-3ethylhexyloxy)-1,4-phenylene vinylene) (MEH-PPV). The optical resonator consists of the octagonal quasi-crystal for light localization in-plane by the bandgap effect and the distributed Bragg reflector introduced between the slab-substrate interface by inhibiting the scattering and absorption of light in the substrate to achieve vertical confinement of the light. A modified point-defect traps and localizes photons into the microcavity, forcing the wave oscillation along the vertical waveguide. The experimental results show that the single-mode lasing action by optical pumping is observed at 602.2 nm with an FWHM of 0.7 nm. The threshold of lasing is lowered to 6.9 μJ/pulse.
Influenza neuraminidase (NA) has received increasing attention as an effective vaccine target. However, its mutational tolerance is not well characterized. Here, the fitness effects of >6,000 mutations in human H3N2 NA are probed using deep mutational scanning. Our result shows that while its antigenic regions have high mutational tolerance, there are solvent-exposed regions with low mutational tolerance. We also find that protein stability is a major determinant of NA mutational fitness. The deep mutational scanning result correlates well with mutational fitness inferred from natural sequences using a protein language model, substantiating the relevance of our findings to the natural evolution of circulating strains. Additional analysis further suggests that human H3N2 NA is far from running out of mutations despite already evolving for >50 years. Overall, this study advances our understanding of the evolutionary potential of NA and the underlying biophysical constraints, which in turn provide insights into NA-based vaccine design.
Antibody discovery is crucial for developing therapeutics and vaccines as well as understanding adaptive immunity. However, the lack of approaches to synthesize antibodies with defined sequences in a high-throughput manner represents a major bottleneck in antibody discovery. Here, we presented oPool
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