Recently, metasurfaces composed of artificially fabricated subwavelength structures have shown remarkable potential for the manipulation of light with unprecedented functionality. Here, we first demonstrate a metasurface application to realize a compact near-eye display system for augmented reality with a wide field of view. A key component is a see-through metalens with an anisotropic response, a high numerical aperture with a large aperture, and broadband characteristics. By virtue of these high-performance features, the metalens can overcome the existing bottleneck imposed by the narrow field of view and bulkiness of current systems, which hinders their usability and further development. Experimental demonstrations with a nanoimprinted large-area see-through metalens are reported, showing full-color imaging with a wide field of view and feasibility of mass production. This work on novel metasurface applications shows great potential for the development of optical display systems for future consumer electronics and computer vision applications.
In nutrient-starved bacteria, RelA and SpoT proteins have key roles in reducing cell growth and overcoming stresses. Here we identify functional SpoT orthologs in metazoa (named Mesh1, encoded by HDDC3 in human and Q9VAM9 in Drosophila melanogaster) and reveal their structures and functions. Like the bacterial enzyme, Mesh1 proteins contain an active site for ppGpp hydrolysis and a conserved His-Asp-box motif for Mn(2+) binding. Consistent with these structural data, Mesh1 efficiently catalyzes hydrolysis of guanosine 3',5'-diphosphate (ppGpp) both in vitro and in vivo. Mesh1 also suppresses SpoT-deficient lethality and RelA-induced delayed cell growth in bacteria. Notably, deletion of Mesh1 (Q9VAM9) in Drosophila induces retarded body growth and impaired starvation resistance. Microarray analyses reveal that the amino acid-starved Mesh1 null mutant has highly downregulated DNA and protein synthesis-related genes and upregulated stress-responsible genes. These data suggest that metazoan SpoT orthologs have an evolutionarily conserved function in starvation responses.
We demonstrate tuning of hole injection barriers in bottom contact triisopropylsilylethynyl pentacene ͑TIPS-pentacene͒ organic thin film transistors ͑OTFTs͒ by forming the self-assembled monolayers ͑SAMs͒ of thiophenol, 4-fluorothiophenol, or pentafluorothiophenol on the pristine Ag electrode. The work functions of SAM-treated Ag electrodes are measured by Kelvin probe method. The TIPS-pentacene OTFT devices were fabricated by a drop-cast method with a micropipette like an inkjet printing. The OTFTs with pentafluorothiophenol-Ag electrodes as source and drain exhibit carrier mobility of 0.17 cm 2 / V s and on/off current ratio of 10 5 because of almost no hole injection barrier to TIPS pentacenes. The SAM-treated Ag electrodes are robust over repeated electrical scans of 100 cycles.
Delivering the goods: Multifunctional, self‐assembled, polymeric nanoparticles for the simultaneous delivery of small‐molecule drugs and siRNA have been synthesized. The nanoparticles are composed of biodegradable hyaluronic acid, for tumor targeting and cellular delivery, and a high siRNA binding affinity is provided by a ZnII‐dipicolylamine analogue as an artificial phosphate‐binding receptor (see scheme).
A coumarin-based fluorescent chemodosimeter with a salicylaldehyde functionality as a binding site has been developed for selective detection of cyanide anions over other anions in water at biological pH.
In paleoparasitology, which is the study of ancient parasite species, parasite egg remnants in archaeological samples are examined by microscopic or molecular analysis. The parasitological information thus obtained can inform speculation about the parasite-infection patterns that prevailed in ancient societies. The current analysis of ancient feces removed from Joseon period mummies adds six new paleoparasitological outcomes to the existing pool of mummy parasitism data already maintained in South Korea. The current microscopic examination revealed the ancient parasite eggs of Trichuris, Clonorchis, Paragonimus, Ascaris, and Taenia in the Joseon mummy feces. When the updated Joseon data were compared with the 20th-century National Survey statistics of South Korea, clear differences could be observed between ancient and modern parasite infection rates. These results will yield invaluable insights-unobtainable by conventional historical investigation-that contribute to the knowledge base on the parasitism of pre-industrial East Asian societies.
The hypersensitive response and pathogenicity (hrp) type III secretion system (T3SS) is a key pathogenicity factor in Erwinia amylovora. Previous studies have demonstrated that the T3SS in E. amylovora is transcriptionally regulated by a sigma factor cascade. In this study, the role of the bacterial alarmone ppGpp in activating the T3SS and virulence of E. amylovora was investigated using ppGpp mutants generated by Red recombinase cloning. The virulence of a ppGpp-deficient mutant (ppGpp 0 ) as well as a dksA mutant of E. amylovora was completely impaired, and bacterial growth was significantly reduced, suggesting that ppGpp is required for full virulence of E. amylovora. Expression of T3SS genes was greatly downregulated in the ppGpp 0 and dksA mutants. Western blotting showed that accumulations of the HrpA protein in the ppGpp 0 and dksA mutants were about 10 and 4%, respectively, of that in the wild-type strain. Furthermore, higher levels of ppGpp resulted in a reduced cell size of E. amylovora. Moreover, serine hydroxamate and ␣-methylglucoside, which induce amino acid and carbon starvation, respectively, activated hrpA and hrpL promoter activities in hrp-inducing minimal medium. These results demonstrated that ppGpp and DksA play central roles in E. amylovora virulence and indicated that E. amylovora utilizes ppGpp as an internal messenger to sense environmental/nutritional stimuli for regulation of the T3SS and virulence. IMPORTANCEThe type III secretion system (T3SS) is a key pathogenicity factor in Gram-negative bacteria. Fully elucidating how the T3SS is activated is crucial for comprehensively understanding the function of the T3SS, bacterial pathogenesis, and survival under stress conditions. In this study, we present the first evidence that the bacterial alarmone ppGpp-mediated stringent response activates the T3SS through a sigma factor cascade, indicating that ppGpp acts as an internal messenger to sense environmental/nutritional stimuli for the regulation of the T3SS and virulence in plant-pathogenic bacteria. Furthermore, the recovery of an spoT null mutant, which displayed very unique phenotypes, suggested that small proteins containing a single ppGpp hydrolase domain are functional.E rwinia amylovora causes a devastating fire blight disease of apples and pears, which results in severe economic losses to growers around the world (1, 2). E. amylovora is closely related to members of the Enterobacteriaceae family, including many important human pathogens, such as Escherichia coli, Yersinia pestis, and Salmonella enterica (3). Studies have revealed that the hypersensitive response and pathogenicity (hrp) type III secretion system (T3SS) is a major pathogenicity factor in E. amylovora (4-7). The hrp T3SS genes are carried on a pathogenicity island (8), and the alternative sigma factor HrpL, a member of the ECF subfamily of sigma factors, serves as the master regulator to control the expression of the structural and effector genes by binding to a consensus sequence known as the hrp box (9-13)...
Joseon mummies have proved to be excellent subjects for scientific research on the health and disease statuses of pre-modern Korean peoples. Despite its academic significance, the origins of the Hoegwakmyo tomb in which the Joseon mummy was discovered have not yet been entirely revealed. Meanwhile, over the past several decades, there have been some reports on mummies and cultural artifacts preserved very well in the tombs of several Chinese dynasties (especially Song, Yuan, Ming and Qing). Although the Chinese tombs were very diverse in structure, we note that some graves among them were structurally very similar to Joseon Hoegwakmyo tombs. Before the Hoegwakmyo tomb in Korea, there were already similar tombs in China, inside which dead persons were mummified like the Joseon mummies. Considering that the Hoegwakmyo tomb of the Joseon Dynasty was established by the influence of the Confucian ideology, the Korean and Chinese mummies might share common cultural origins in history.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.