This paper describes the use of physical unclonable functions (PUFs) in low-cost authentication and key generation applications. First, it motivates the use of PUFs versus conventional secure ...nonvolatile memories and defines the two primary PUF types: "strong PUFs" and "weak PUFs." It describes strong PUF implementations and their use for low-cost authentication. After this description, the paper covers both attacks and protocols to address errors. Next, the paper covers weak PUF implementations and their use in key generation applications. It covers error-correction schemes such as pattern matching and index-based coding. Finally, this paper reviews several emerging concepts in PUF technologies such as public model PUFs and new PUF implementation technologies.
The cereal endosperm is a major factor determining seed size and shape. However, the molecular mechanisms of endosperm development are not fully understood. Long noncoding RNAs (lncRNAs) function in ...various biological processes. Here we show a lncRNA, MISSEN, that plays an essential role in early endosperm development in rice (Oryza sativa). MISSEN is a parent-of-origin lncRNA expressed in endosperm, and negatively regulates endosperm development, leading to a prominent dent and bulge in the seed. Mechanistically, MISSEN functions through hijacking a helicase family protein (HeFP) to regulate tubulin function during endosperm nucleus division and endosperm cellularization, resulting in abnormal cytoskeletal polymerization. Finally, we revealed that the expression of MISSEN is inhibited by histone H3 lysine 27 trimethylation (H3K27me3) modification after pollination. Therefore, MISSEN is the first lncRNA identified as a regulator in endosperm development, highlighting the potential applications in rice breeding.
The high fracture toughness of mollusk nacre is predominantly attributed to the structure‐associated extrinsic mechanisms such as platelet sliding and crack deflection. While the nacre‐mimetic ...structures are widely adopted in artificial ceramics, the extrinsic mechanisms are often weakened by the relatively low tensile strength of the platelets with a large aspect ratio, which makes the fracture toughness of these materials much lower than expected. Here, it is demonstrated that the fracture toughness of artificial nacre materials with high inorganic contents can be improved by residual stress‐induced platelet strengthening, which can catalyze more effective extrinsic toughening mechanisms that are specific to the nacre‐mimetic structures. Thereby, while the absolute fracture toughness of the materials is not comparable with advanced ceramic‐based composites, the toughness amplification factor of the material reaches 16.1 ± 1.1, outperforming the state‐of‐the‐art biomimetic ceramics. The results reveal that, with the merit of nacre‐mimetic structural designs, the overall fracture toughness of the artificial nacre can be improved by the platelet strengthening through extrinsic toughening mechanisms, although the intrinsic fracture toughness may decrease at platelet level due to the strengthening. It is anticipated that advanced structural ceramics with exceeding performance can be fabricated through these unconventional strategies.
This work illustrates an anti‐intuitive strategy that, with the merit of biomimetic designs, residual stress that is conventionally harmful to ceramics can inversely help improve the fracture toughness of biomimetic ceramics through nanoscale residual stress‐induced platelet strengthening. This provides new insights into the design principles of nacre‐like materials at the bottom level.
Growing evidence indicates that circulating lactoferrin (Lf) is implicated in peripheral cholesterol metabolism disorders. It has emerged that the distribution of Lf changes in astrocytes of aging ...brains and those exhibiting neurodegeneration; however, its physiological and/or pathological role remains unknown. Here, we demonstrate that astrocyte‐specific knockout of Lf (designated cKO) led to decreased body weight and cognitive abnormalities during early life in mice. Accordingly, there was a reduction in neuronal outgrowth and synaptic structure in cKO mice. Importantly, Lf deficiency in the primary astrocytes led to decreased sterol regulatory element binding protein 2 (Srebp2) activation and cholesterol production, and cholesterol content in cKO mice and/or in astrocytes was restored by exogenous Lf or a Srebp2 agonist. Moreover, neuronal dendritic complexity and total dendritic length were decreased after culture with the culture medium of the primary astrocytes derived from cKO mice and that this decrease was reversed after cholesterol supplementation. Alternatively, these alterations were associated with an activation of AMP‐activated protein kinase (AMPK) and inhibition of SREBP2 nuclear translocation. These data suggest that astrocytic Lf might directly or indirectly control in situ cholesterol synthesis, which may be implicated in neurodevelopment and several neurological diseases.
Main Points
Astrocytic lactoferrin (Lf) loss causes growth retardation and intellectual disabilities in mice.
Astrocytic Lf loss leads to a reduction in neuronal outgrowth and synaptic structure.
• Astrocytic lactoferrin controls in situ cholesterol synthesis in mice.
Inorganic perovskite ferroelectrics are widely used in nonvolatile memory elements, capacitors, and sensors because of their excellent ferroelectric and other properties. Organic ferroelectrics are ...desirable for their mechanical flexibility, low weight, environmentally friendly processing, and low processing temperatures. Although almost a century has passed since the first ferroelectric, Rochelle salt, was discovered, examples of highly desirable organic perovskite ferroelectrics are lacking. We found a family of metal-free organic perovskite ferroelectrics with the characteristic three-dimensional structure, among which MDABCO (
-methyl-
-diazabicyclo2.2.2octonium)-ammonium triiodide has a spontaneous polarization of 22 microcoulombs per square centimeter close to that of barium titanate (BTO), a high phase transition temperature of 448 kelvins (above that of BTO), and eight possible polarization directions. These attributes make it attractive for use in flexible devices, soft robotics, biomedical devices, and other applications.
Abstract
With the goal of charting plant transcriptional regulatory maps (i.e. transcription factors (TFs), cis-elements and interactions between them), we have upgraded the TF-centred database ...PlantTFDB (http://planttfdb.cbi.pku.edu.cn/) to a plant regulatory data and analysis platform PlantRegMap (http://plantregmap.cbi.pku.edu.cn/) over the past three years. In this version, we updated the annotations for the previously collected TFs and set up a new section, ‘extended TF repertoires’ (TFext), to allow users prompt access to the TF repertoires of newly sequenced species. In addition to our regular TF updates, we are dedicated to updating the data on cis-elements and functional interactions between TFs and cis-elements. We established genome-wide conservation landscapes for 63 representative plants and then developed an algorithm, FunTFBS, to screen for functional regulatory elements and interactions by coupling the base-varied binding affinities of TFs with the evolutionary footprints on their binding sites. Using the FunTFBS algorithm and the conservation landscapes, we further identified over 20 million functional TF binding sites (TFBSs) and two million functional interactions for 21 346 TFs, charting the functional regulatory maps of these 63 plants. These resources are publicly available at PlantRegMap (http://plantregmap.cbi.pku.edu.cn/) and a cloud-based mirror (http://plantregmap.gao-lab.org/), providing the plant research community with valuable resources for decoding plant transcriptional regulatory systems.
Hybrid perovskite materials are famous for their great application potential in photovoltaics and optoelectronics. Among them, lead‐iodide‐based perovskites receive great attention because of their ...good optical absorption ability and excellent electrical transport properties. Although many believe the ferroelectric photovoltaic effect (FEPV) plays a crucial role for the high conversion efficiency, the ferroelectricity in CH3NH3PbI3 is still under debate, and obtaining ferroelectric lead iodide perovskites is still challenging. In order to avoid the randomness and blindness in the conventional method of searching for perovskite ferroelectrics, a design strategy of fluorine modification is developed. As a demonstration, a nonpolar lead iodide perovskite is modified and a new 2D fluorinated layered hybrid perovskite material of (4,4‐difluorocyclohexylammonium)2PbI4, 1, is obtained, which possesses clear ferroelectricity with controllable spontaneous polarization. The direct bandgap of 2.38 eV with strong photoluminescence also guarantees the direct observation of polarization‐induced FEPV. More importantly, the 2D structure and fluorination are also expected to achieve both good stability and charge transport properties. 1 is not only a 2D fluorinated lead iodide perovskite with confirmed ferroelectricity, but also a great platform for studying the effect of ferroelectricity and FEPV in the context of lead halide perovskite solar cells and other optoelectronic applications.
Through a design strategy of fluorine modification, a nonpolar lead iodide perovskite is modified and a new 2D fluorinated layered hybrid perovskite material of (4,4‐difluorocyclohexylammonium)2PbI4 is obtained, which possesses clear ferroelectricity with controllable spontaneous polarization and ferroelectric photovoltaic effect. The discovery of such a material provides a great platform for the fundamental study of lead halide perovskite solar cells and other optoelectronic applications.
Ischemia-reperfusion injury is associated with serious clinical manifestations, including myocardial hibernation, acute heart failure, cerebral dysfunction, gastrointestinal dysfunction, systemic ...inflammatory response syndrome, and multiple organ dysfunction syndrome. Ischemia-reperfusion injury is a critical medical condition that poses an important therapeutic challenge for physicians. In this review article, we present recent advances focusing on the basic pathophysiology of ischemia-reperfusion injury, especially the involvement of reactive oxygen species and cell death pathways. The involvement of the NADPH oxidase system, nitric oxide synthase system, and xanthine oxidase system are also described. When the blood supply is re-established after prolonged ischemia, local inflammation and ROS production increase, leading to secondary injury. Cell damage induced by prolonged ischemia-reperfusion injury may lead to apoptosis, autophagy, necrosis, and necroptosis. We highlight the latest mechanistic insights into reperfusion-injury-induced cell death via these different processes. The interlinked signaling pathways of cell death could offer new targets for therapeutic approaches. Treatment approaches for ischemia-reperfusion injury are also reviewed. We believe that understanding the pathophysiology ischemia-reperfusion injury will enable the development of novel treatment interventions.
With the goal of providing a comprehensive, high-quality resource for both plant transcription factors (TFs) and their regulatory interactions with target genes, we upgraded plant TF database ...PlantTFDB to version 4.0 (http://planttfdb.cbi.pku.edu.cn/). In the new version, we identified 320 370 TFs from 165 species, presenting a more comprehensive genomic TF repertoires of green plants. Besides updating the pre-existing abundant functional and evolutionary annotation for identified TFs, we generated three new types of annotation which provide more directly clues to investigate functional mechanisms underlying: (i) a set of high-quality, non-redundant TF binding motifs derived from experiments; (ii) multiple types of regulatory elements identified from high-throughput sequencing data; (iii) regulatory interactions curated from literature and inferred by combining TF binding motifs and regulatory elements. In addition, we upgraded previous TF prediction server, and set up four novel tools for regulation prediction and functional enrichment analyses. Finally, we set up a novel companion portal PlantRegMap (http://plantregmap.cbi.pku.edu.cn) for users to access the regulation resource and analysis tools conveniently.
A novel copper‐catalyzed regiodivergent alkylboration of alkenes with bis(pinacolato)diboron and alkyl halides has been developed. The regioselectivity of the alkylboration was controlled by subtle ...differences in the ligand structure. The reaction thus enables the practical, regiodivergent synthesis of two different alkyl boronic esters with complex structures from a single alkene.
One way or another: The copper‐catalyzed regiodivergent alkylboration of alkenes with bis(pinacolato)diboron and alkyl halides is described. The regioselectivity of the carboboration can be controlled by fine‐tuning the ligand structure.
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