An optimal single-photon source should deterministically deliver one, and only one, photon at a time, with no trade-off between the source’s efficiency and the photon indistinguishability. However, ...all reported solid-state sources of indistinguishable single photons had to rely on polarization filtering, which reduced the efficiency by 50%, fundamentally limiting the scaling of photonic quantum technologies. Here, we overcome this long-standing challenge by coherently driving quantum dots deterministically coupled to polarization-selective Purcell microcavities. We present two examples: narrowband, elliptical micropillars and broadband, elliptical Bragg gratings. A polarization-orthogonal excitation–collection scheme is designed to minimize the polarization filtering loss under resonant excitation. We demonstrate a polarized single-photon efficiency of 0.60 ± 0.02 (0.56 ± 0.02), a single-photon purity of 0.975 ± 0.005 (0.991 ± 0.003) and an indistinguishability of 0.975 ± 0.006 (0.951 ± 0.005) for the micropillar (Bragg grating) device. Our work provides promising solutions for truly optimal single-photon sources combining near-unity indistinguishability and near-unity system efficiency simultaneously.
N6‐methyladenosine (m6A) is a well‐known modification of RNA. However, as a key m6A methyltransferase, METTL16 has not been thoroughly studied in gastric cancer (GC). Here, the biological role of ...METTL16 in GC and its underlying mechanism was studied. Immunohistochemistry was used to detect the expression of METTL16 and relationship between METTL16 level and prognosis of GC was analysed. CCK8, colony formation assay, EdU assay and xenograft mouse model were used to study the effect of METTL16. Regulatory mechanism of METTL16 in the progression of GC was studied through flow cytometry analysis, RNA degradation assay, methyltransferase inhibition assay, RT‐qPCR and Western blotting. METTL16 was highly expressed in GC cells and tissues and was associated with prognosis. In vitro and in vivo experiments confirmed that METTL16 promoted proliferation of GC cells and tumour growth. Furthermore, down‐regulation of METTL16 inhibited proliferation by G1/S blocking. Significantly, we identified cyclin D1 as a downstream effector of METTL16. Knock‐down METTL16 decreased the overall level of m6A and the stability of cyclin D1 mRNA in GC cells. Meanwhile, inhibition of methyltransferase activity reduced the level of cyclin D1. METTL16‐mediated m6A methylation promotes proliferation of GC cells through enhancing cyclin D1 expression.
Designing well‐defined interfacial chemical bond bridges is an effective strategy to optimize the catalytic activity of metal–organic frameworks (MOFs), but it remains challenging. Herein, a facile ...in situ growth strategy is reported for the synthesis of tightly connected 2D/2D heterostructures by coupling MXene with CoBDC nanosheets. The multifunctional MXene nanosheets with high conductivity and ideal hydrophilicity as bridging carriers can ensure structural stability and sufficient exposure to active sites. Moreover, the Co–O–Ti bond bridging formed at the interface effectively triggers the charge transfer and modulates the electronic structure of the Co‐active site, which enhances the reaction kinetics. As a result, the optimized CoBDC/MXene exhibits superior hydrogen evolution reaction (HER) activity with low overpotentials of 29, 41, and 76 mV at 10 mA cm−2 in alkaline, acidic, and neutral electrolytes, respectively, which is comparable to commercial Pt/C. Theoretical calculation demonstrates that the interfacial bridging‐induced electron redistribution optimizes the free energy of water dissociation and hydrogen adsorption, resulting in improved hydrogen evolution. This study not only provides a novel electrocatalyst for efficient HER at all pH conditions but also opens up a new avenue for designing highly active catalytic systems.
A novel CoBDC/MXene electrocatalyst with 2D/2D heterostructure is prepared by a facile in situ growth strategy, in which the formation of interfacial Co–O–Ti bridges effectively tunes the electron distribution and catalytic reaction energy barrier, leading to ultralow hydrogen evolution reaction overpotentials at all pH conditions.
Gaussian accelerated molecular dynamics (GaMD) is a robust computational method for simultaneous unconstrained enhanced sampling and free energy calculations of biomolecules. It works by adding a ...harmonic boost potential to smooth biomolecular potential energy surface and reduce energy barriers. GaMD greatly accelerates biomolecular simulations by orders of magnitude. Without the need to set predefined reaction coordinates or collective variables, GaMD provides unconstrained enhanced sampling and is advantageous for simulating complex biological processes. The GaMD boost potential exhibits a Gaussian distribution, thereby allowing for energetic reweighting via cumulant expansion to the second order (i.e., “Gaussian approximation”). This leads to accurate reconstruction of free energy landscapes of biomolecules. Hybrid schemes with other enhanced sampling methods, such as the replica‐exchange GaMD (rex‐GaMD) and replica‐exchange umbrella sampling GaMD (GaREUS), have also been introduced, further improving sampling and free energy calculations. Recently, new “selective GaMD” algorithms including the Ligand GaMD (LiGaMD) and Peptide GaMD (Pep‐GaMD) enabled microsecond simulations to capture repetitive dissociation and binding of small‐molecule ligands and highly flexible peptides. The simulations then allowed highly efficient quantitative characterization of the ligand/peptide binding thermodynamics and kinetics. Taken together, GaMD and its innovative variants are applicable to simulate a wide variety of biomolecular dynamics, including protein folding, conformational changes and allostery, ligand binding, peptide binding, protein–protein/nucleic acid/carbohydrate interactions, and carbohydrate/nucleic acid interactions. In this review, we present principles of the GaMD algorithms and recent applications in biomolecular simulations and drug design.
This article is categorized under:
Structure and Mechanism > Computational Biochemistry and Biophysics
Molecular and Statistical Mechanics > Molecular Dynamics and Monte‐Carlo Methods
Molecular and Statistical Mechanics > Free Energy Methods
Gaussian accelerated molecular dynamics (GaMD) and its applications to a wide range of biological systems.
A
bstract
Applying the dispersion approach we compute perturbative QCD corrections to the power suppressed soft contribution of
B
→
γℓν
at leading twist. QCD factorization for the
B
→
γ
*
form ...factors is demonstrated explicitly for the hard-collinear transverse polarized photon at one loop, with the aid of the method of regions. While the one-loop hard function is identical to the matching coefficient of the QCD weak current
ūγ
μ
⊥
(1 −
γ
5
)
b
in soft-collinear effective theory, the jet function from integrating out the hard-collinear fluctuations differs from the corresponding one entering the factorization formula of
B
→
γℓν
, due to the appearance of an additional hard-collinear momentum mode. Furthermore, we evaluate the sub-leading power contribution to the
B
→
γ
form factors from the three-particle
B
-meson distribution amplitudes (DAs) at tree level, with the dispersion approach. The soft contribution to the
B
→
γ
form factors from the three-particle
B
-meson DAs is shown to be of the same power compared with the corresponding hard correction, in contrast to the two-particle counterparts. Numerically the next-to-leading-order QCD correction to the soft two-particle contribution in
B
→
γ
form factors will induce an approximately (10 ∼ 20)% shift to the tree-level contribution at
λ
B
(
μ
0
) = 354 MeV. Albeit of power suppression parametrically, the soft two-particle correction can decrease the leading power predictions for the
B
→
γ
form factors by an amount of (10 ∼ 30)% with the same value of
λ
B
(
μ
0
). Employing the phenomenological model of the three-particle
B
-meson DAs inspired by a QCD sum rule analysis, the three-particle contribution to the
B
→
γ
form factors is predicted to be of
O
(1%), at leading order in
α
s
, with the default theory inputs. Finally, we explore theory constraints on the inverse moment of the leading-twist
B
-meson DA
λ
B
from the recent Belle measurements of the partial branching fractions of
B
→
γℓν
, taking into account the newly computed contributions to the
B
→
γ
form factors at subleading power.
The generative adversarial network (GAN) framework has emerged as a powerful tool for various image and video synthesis tasks, allowing the synthesis of visual content in an unconditional or ...input-conditional manner. It has enabled the generation of high-resolution photorealistic images and videos, a task that was challenging or impossible with prior methods. It has also led to the creation of many new applications in content creation. In this article, we provide an overview of GANs with a special focus on algorithms and applications for visual synthesis. We cover several important techniques to stabilize GAN training, which has a reputation for being notoriously difficult. We also discuss its applications to image translation, image processing, video synthesis, and neural rendering.
COVID‐19 pandemic, caused by severe acute respiratory syndrome coronavirus 2, has resulted in global social and economic disruption, putting the world economy to the largest global recession since ...the Great Depression. To control the spread of COVID‐19, cutting off the transmission route is a critical step. In this work, the efficient inactivation of human coronavirus with photodynamic therapy (PDT) by employing photosensitizers with aggregation‐induced emission characteristics (DTTPB) is reported. DTTPB is designed to bear a hydrophilic head and two hydrophobic tails, mimicking the structure of phospholipids on biological membranes. DTTPB demonstrates a broad absorption band covering the whole visible light range and high molar absorptivity, as well as excellent reactive oxygen species sensitizing ability, making it an excellent candidate for PDT. Besides, DTTPB can target membrane structure, and bind to the envelope of human coronaviruses. Upon light irradiation, DTTPB demonstrates highly effective antiviral behavior: human coronavirus treated with DTTPB and white‐light irradiation can be efficiently inactivated with complete loss of infectivity, as revealed by the significant decrease of virus RNA and proteins in host cells. Thus, DTTPB sensitized PDT can efficiently prevent the infection and the spread of human coronavirus, which provides a new avenue for photodynamic combating of COVID‐19.
In this work, we report the application of a novel photosensitizer, DTTPB, with aggregation‐induced emission characteristics for photodynamic inactivation of human coronaviruses. With high molar absorbance coefficient, broad absorption band covering the whole white light region, and high membrane targeting and ROS sensitizing efficiency, DTTPB could effectively inactivate human coronaviruses and may contribute to preventing the spread of COVID‐19 pandemic.
The root of Polygonum multiflorum Thunb （PM） has been used in China to treat a variety of diseases, such as constipation, early graying of the hair and hyperlipemia. Recent evidence shows that PM ...causes idiosyncratic drug-induced liver injury （IDILI） in humans. In this study, we investigated the molecular basis of PM-induced liver injury in a rat model of IDILI based on a non-hepatotoxic dose of LPS. SD rats were orally administered 3 potentially hepatotoxic compounds of PM： cis-stilbene glucoside （cis-SG, 50 mg/kg）, trans-SG （50 mg/kg） or emodin （5 mg/kg）, followed by injection of LPS （2.8 mg/kg, iv）. Serum and liver histology were evaluated 7 h after LPS injection. Among the 3 compounds tested, cis-SG, but not emodin or trans-SG, induced severe liver injury in rats when combined with LPS. The levels of AST and ALT in plasma and inflammatory cytokines in both plasma and liver tissues were markedly elevated. The liver tissues showed increased injury, hepatocyte apoptosis, and macrophage infiltration, and decreased cell proliferation. Microarray analysis revealed a negative correlation between peroxisome proliferator-activated receptor-y （PPAR-y） and LPS/cis-SG-induced liver injury. Immunohistochemical staining and RT-PCR results further confirmed that cis-SG significantly inhibited activation of the PPAR-~ pathway in the liver tissues of LPS/cis-SG-treated rats. Pre-treatment with a PPAR-y agonist pioglitazone （500 g/kg, ig） reversed LPS/ cis-SG-induced liver injury, which was associated with inhibiting the nuclear factor kappa B （NF-KB） pathway. These data demonstrate that c/s-stilbene glucoside induces immunological idiosyncratic hepatotoxicity through suppressing PPAR-γ in a rat model of IDILl.
A typical feature of marine foods is that they are rich in docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), which have formed a large-scale global industry. DHA/EPA phospholipids (PLs) are ...ubiquitous in marine foods and are the main DHA/EPA molecular forms in fish roe, shrimp and shellfish. Much attention has been focused on the bioavailability and health benefits that are influenced by the type and esterified form of dietary fatty acids. Recently, numerous findings have suggested that dietary DHA/EPA-PLs are superior to the triacylglycerol (TAG) or ethyl ester forms in exerting their functional properties through specific mechanisms of action. However, there is no comprehensive review covering the health benefits of dietary marine DHA/EPA-enriched PLs. In this paper, we review publications on the nutritional functions of DHA/EPA-enriched glycerophospholipids, including the effects on brain function, antitumor activity, lipid metabolism, and glucose metabolism. The current research status regarding the active ingredients, sources, models, treatment, duration, and mechanisms are presented. In addition, the way in which the structure-activity relationship of DHA/EPA-PLs is affected by ester-bond structure at the sn-1 position, fatty acid at the sn-2 position and polar head group at the sn-3 position is also reviewed. DHA/EPA-PLs are one of the major n-3 long-chain polyunsaturated fatty acid dietary forms in our diet, and we should maximize the ability to fully exploit the nutritional properties of DHA/EPA.
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Strong near‐surface electromagnetic field formed by collective oscillation of electrons on Cu nanostructure a shows a strong dependence on geometry, offering a promising approach to boost the light ...absorption of ZnO photoactive layers with enhanced plasmon scattering. Here, a facile way to fabricate UV photodetectors with tunable configuration of the self‐assembled Cu nanostructures on ZnO thin films is reported. The incident lights are effectively confined in ZnO photoactive layers with the existence of the uplayer Cu nanostructures, and the interdiffusion of Cu atoms during fabrication of the Cu nanostructures can improve the carrier transfer in ZnO thin films. The optical properties of the hybrid architectures are successfully tailored over a control of the geometric evolution of the Cu nanostructures, resulting in significantly enhanced photocurrent and responsivity of 2.26 mA and 234 A W−1 under a UV light illumination of 0.62 mW cm−2 at 10 V, respectively. The photodetectors also exhibit excellent reproducibility, stability, and UV–visible rejection ratio (R370 nm/R500 nm) of ≈370, offering an approach of high‐performance UV photodetectors for practical applications.
Strong near‐surface electromagnetic field formed on Cu nanostructures offers a promising approach to boost the light absorption of ZnO photoactive layers. Here, an ultrahigh responsivity Cu nanostructure/ZnO quantum dot hybrid architecture UV photodetector is achieved by systematically controlling the surface morphology of self‐assembled Cu nanostructures. The internal relation of the morphological evolution of Cu nanostructures and enhanced responsivity is revealed.
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