The coherent interaction between quantum emitters and photonic modes in cavities underlies many of the current strategies aiming at generating and controlling photonic quantum states. A plasmonic ...nanocavity provides a powerful solution for reducing the effective mode volumes down to nanometre scale, but spatial control at the atomic scale of the coupling with a single molecular emitter is challenging. Here we demonstrate sub-nanometre spatial control over the coherent coupling between a single molecule and a plasmonic nanocavity in close proximity by monitoring the evolution of Fano lineshapes and photonic Lamb shifts in tunnelling electron-induced luminescence spectra. The evolution of the Fano dips allows the determination of the effective interaction distance of ∼1 nm, coupling strengths reaching ∼15 meV and a giant self-interaction induced photonic Lamb shift of up to ∼3 meV. These results open new pathways to control quantum interference and field-matter interaction at the nanoscale.
•Self-adaptive permutation–diffusion and DNA random encoding are developed.•DNA random encoding firstly disarranges the bit distribution of the plaintext.•The quantization processes are disturbed by ...the intrinsic features of the plaintext.•The introduced disturbances can be automatically retrieved in the decryption end.•The reusability of the random variables dramatically promote the efficiency.
This paper presents a solution for secure and efficient image encryption with the help of self-adaptive permutation–diffusion and DNA random encoding. The plain image is firstly converted to DNA sequence using random encoding rules, so as to disarrange the bit distribution of the plaintext. A self-adaptive permutation–diffusion procedure is subsequently introduced for further encryption. The quantization processes of the permutation and diffusion procedures are disturbed by the intrinsic features of the plaintext, with the introduced disturbances can be automatically retrieved in the decryption end. The security of the system originates from the plaintext-related quantization of the encryption process which makes the cryptosystem secure against plaintext attack. Besides, the reusability of the random variables can dramatically promote the efficiency of the cryptosystem, which renders great potential for real-time secure image applications.
Pleiotropy refers to the phenomenon of a single mutation or gene affecting multiple distinct phenotypic traits and has broad implications in many areas of biology. Due to its central importance, ...pleiotropy has also been extensively modeled, albeit with virtually no empirical basis. Analyzing phenotypes of large numbers of yeast, nematode, and mouse mutants, we here describe the genomic patterns of pleiotropy. We show that the fraction of traits altered appreciably by the deletion of a gene is minute for most genes and the gene–trait relationship is highly modular. The standardized size of the phenotypic effect of a gene on a trait is approximately normally distributed with variable SDs for different genes, which gives rise to the surprising observation of a larger per-trait effect for genes affecting more traits. This scaling property counteracts the pleiotropy-associated reduction in adaptation rate (i.e., the “cost of complexity”) in a nonlinear fashion, resulting in the highest adaptation rate for organisms of intermediate complexity rather than low complexity. Intriguingly, the observed scaling exponent falls in a narrow range that maximizes the optimal complexity. Together, the genome-wide observations of overall low pleiotropy, high modularity, and larger per-trait effects from genes of higher pleiotropy necessitate major revisions of theoretical models of pleiotropy and suggest that pleiotropy has not only allowed but also promoted the evolution of complexity.
We consider a supply chain with one buyer and two suppliers who are subject to disruptions and whose likelihoods of disruption are their private information. In such a setting, does the buyer benefit ...from engaging the services of a better-informed procurement service provider (PSP) compared to procuring directly from the suppliers? Intuition might suggest that hiring a PSP is always the right choice because the PSP’s knowledge of the supply base improves supplier selection and management. On the other hand, earlier studies prove that using a PSP purely for its superior knowledge about supply costs is always worse for a buyer than contracting with the suppliers directly. Our answer to this research question is more nuanced. Contrary to the findings of earlier studies, we find that the buyer may benefit from using a PSP. We identify, quantify, and explain all of the benefits and the costs of using a PSP, and describe conditions under which the benefits exceed the costs. The benefits of using a PSP are derived when one supplier is of high reliability and the other is of low reliability, from a reduction of informational costs due to implicit supplier collusion facilitated by the PSP and an improvement of supply availability. The costs of using a PSP are derived when both suppliers are of low reliability, from the loss of direct control over the supplier’s production actions, which leads to reduced supply availability and increased informational costs, and from the PSP facilitating implicit supplier collusion. Comparative statics analysis indicates that using the PSP is valuable only if the buyer diversifies with some supplier-type combinations but not others, and that hiring a PSP is not a solution to the problem of an unreliable supply base.
This paper was accepted by Serguei Netessine, operations management
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One-to-one orthologous genes of relatively closely related species are widely assumed to have similar functions and cause similar phenotypes when deleted from the genome. Although this assumption is ...the foundation of comparative genomics and the basis for the use of model organisms to study human biology and disease, its validity is known only from anecdotes rather than from systematic examination. Comparing documented phenotypes of null mutations in humans and mice, we find that >20% of human essential genes have nonessential mouse orthologs. These changes of gene essentiality appear to be associated with adaptive evolution at the protein-sequence, but not gene-expression, level. Proteins localized to the vacuole, a cellular compartment for waste management, are highly enriched among essentiality-changing genes. It is probable that the evolution of the prolonged life history in humans required enhanced waste management for proper cellular function until the time of reproduction, which rendered these vacuole proteins essential and generated selective pressures for their improvement. If our gene sample represents the entire genome, our results would mean frequent changes of phenotypic effects of one-to-one orthologous genes even between relatively closely related species, a possibility that should be considered in comparative genomic studies and in making cross-species inferences of gene function and phenotypic effect.
What kind of genetic variation contributes the most to adaptation is a fundamental question in evolutionary biology. By resequencing genomes of 80 individuals, we inferred the origin of genomic ...variants associated with a complex adaptive syndrome involving multiple quantitative traits, namely, adaptation between high and low altitudes, in the vinous-throated parrotbill (Sinosuthora webbiana) in Taiwan. By comparing these variants with those in the Asian mainland population, we revealed standing variation in 24 noncoding genomic regions to be the predominant genetic source of adaptation. Parrotbills at both high and low altitudes exhibited signatures of recent selection, suggesting that not only the front but also the trailing edges of postglacial expanding populations could be subjected to environmental stresses. This study verifies and quantifies the importance of standing variation in adaptation in a cohort of genes, illustrating that the evolutionary potential of a population depends significantly on its preexisting genetic diversity. These findings provide important context for understanding adaptation and conservation of species in the Anthropocene.
Inspired by the photosynthesis process of natural plants, multifunctional transistors based on natural biomaterial chlorophyll and organic semiconductors (OSCs) are reported. Functions as ...photodetectors (PDs) and light‐stimulated synaptic transistors (LSSTs) can be switched by gate voltage. As PDs, the devices exhibit ultrahigh photoresponsivity up to 2 × 106 A W−1, detectivity of 6 × 1015 Jones, and Iphoto/Idark ratio of 2.7 × 106, which make them among the best reported organic PDs. As LSSTs, important synaptic functions similar to biological synapses are demonstrated, together with a dynamic learning and forgetting process and image‐processing function. Significantly, benefiting from the ultrahigh photosensitivity of chlorophyll, the lowest operating voltage and energy consumption of the LSSTs can be 10−5 V and 0.25 fJ, respectively. The devices also exhibit high flexibility and long‐term air stability. This work provides a new guide for developing organic electronics based on natural biomaterials.
Bioinspired multifunctional organic transistors based on natural chlorophyll and organic semiconductors are fabricated. Phototdetection and light‐stimulated synaptic transistor function can be realized by the single device under gate‐voltage control. The devices show excellent photoresponsivity up to 2 × 106 A W−1 as photodetectors and ultralow operating voltage of 10–5 V as synaptic devices.
The tempo and mode of protein evolution have been central questions in biology. Genomic data have shown a strong influence of the expression level of a protein on its rate of sequence evolution (E-R ...anticorrelation), which is currently explained by the protein misfolding avoidance hypothesis. Here, we show that this hypothesis does not fully explain the E-R anticorrelation, especially for protein surface residues. We propose that natural selection against protein–protein misinteraction, which wastes functional molecules and is potentially toxic, constrains the evolution of surface residues. Because highly expressed proteins are under stronger pressures to avoid misinteraction, surface residues are expected to show an E-R anticorrelation. Our molecular-level evolutionary simulation and yeast genomic analysis confirm multiple predictions of the hypothesis. These findings show a pluralistic origin of the E-R anticorrelation and reveal the role of protein misinteraction, an inherent property of complex cellular systems, in constraining protein evolution.
A series of covalently cross-linked sulfonated poly(imide benzimidazole)s (CBrSPIBIs) were synthesized using 4,4′-bibromomethenyl diphenyl ether as a cross-linker. However, the cross-linked structure ...results in a reduction of ion conductivity due to the blockage of the hydrophilic channel. Thus, the alkaline imidazole ring was used as a cross-linking site and a basic site to absorb phosphoric acid (PA) molecules. Even at a low humidity and PA-doping level, the proton conductivity of the resulting PA-doped CBrSPIBI (PA-CBrSPIBI) membranes is one to two orders of magnitude higher than that of CBrSPIBI and Nafion due to the formation of a new proton transport pathway between PA and sulfonic acid groups. In addition, these membranes display excellent mechanical strength and chemical stability because of the cross-linked structure. The tensile strength of PA-doped cross-linked membranes ranges from 47.2 to 55.5MPa, and they can maintain their integrity and mechanical strength in water for more than two months, which is superior to the corresponding sulfonated polyimide and polybenzimidazole blend membranes.
•Phosphoric acid-doped sulfonated poly(imide benzimidazole) are synthesized.•Benzimidazole ring is used as both a cross-linking site and a basic site.•The resulting membranes have good mechanical strength and chemical stability.•The resulting membranes have a high proton conductivity in high temperature.
Artificial synaptic devices have potential for overcoming the bottleneck of von Neumann architecture and building artificial brain‐like computers. Up to now, developing synaptic devices by utilizing ...biocompatible and biodegradable materials in electronic devices has been an interesting research direction due to the requirements of sustainable development. Here, a degradable photonic synaptic device is reported by combining biomaterials chlorophyll‐a and single‐walled carbon nanotubes (SWCNTs). Several basic synaptic functions, including excitatory postsynaptic current (EPSC), paired pulse facilitation (PPF), transition from short‐term memory (STM) to long‐term memory (LTM), and learning and forgetting behaviors, are successfully emulated through the chlorophyll‐a/SWCNTs synaptic device. Furthermore, decent synaptic behaviors can still be achieved at a low drain voltage of −0.0001 V, which results in quite low energy consumption of 17.5 fJ per pulse. Finally, the degradability of this chlorophyll‐a/SWCNTs transistor array is demonstrated, indicating that the device can be environmentally friendly. This work provides a new guide to the development of next‐generation green and degradable neuromorphic computing electronics.
Degradable photonic synaptic transistors based on chlorophyll‐a and single‐walled carbon nanotubes are designed to successfully emulate the synaptic plasticity. Decent synaptic behaviors can still be achieved at a low voltage of −0.0001 V, which results in low energy consumption of 17.5 fJ per pulse. This work provides a new guide to the development of next‐generation green and degradable neuromorphic computing electronics.
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