In this review, we survey the latest advances in theoretical understanding of bimolecular reaction dynamics in the past decade. The remarkable recent progress in this field has been driven by more ...accurate and efficient ab initio electronic structure theory, effective potential-energy surface fitting techniques, and novel quantum scattering algorithms. Quantum mechanical characterization of bimolecular reactions continues to uncover interesting dynamical phenomena in atom-diatom reactions and beyond, reaching an unprecedented level of sophistication. In tandem with experimental explorations, these theoretical developments have greatly advanced our understanding of key issues in reaction dynamics, such as microscopic reaction mechanisms, mode specificity, product energy disposal, influence of reactive resonances, and nonadiabatic effects.
At present, high-solids anaerobic digestion of sewage sludge has drawn great attention due to the superiority of its small land area footprint and low energy consumption. However, a high organic ...loading rate may cause acids accumulation and ammonia inhibition, thus leading to an inhibited pseudo-steady state in which electron transfer through interspecies hydrogen transfer (IHT) between acetogens and methanogens is blocked. In this study, adding 50 mg/g TS (total solid) magnetite clearly reduced the accumulation of short-chain fatty acids and accelerated methane production by 26.6%. As demonstrated, the individual processes of anaerobic digestion could not be improved by magnetite when methanogenesis was interrupted. Analyzing stable carbon isotopes and investigating the methanogenesis pathways using acetate and H2/CO2 as substrates together proved that direct interspecies electron transfer (DIET) was enhanced by magnetite. Metatranscriptomic analysis and determination of key enzymes showed that IHT could be partially substituted by enhanced DIET, and acetate-dependent methanogenesis was improved after the blockage of electron transfer was scavenged. Additionally, the expression of both pili and c-type cytochromes was found to decrease, indicating that magnetite could replace their roles for efficient electron transfer between acetogens and methanogens; thus, a robust chain of electron transfer was established.
Au‐incorporation is a promising strategy to retard composition‐loss in Pt‐based catalyst. However, the unclear mechanism limits guided catalyst design and the performance optimization. Here, direct ...evidence is provided to validate the outward diffusion of Au atoms in Au‐core/Pt‐based‐shell structures. A Co interlayer is built between the Au‐core and PtCo‐based shell to exclude the possibility of atomic diffusion caused by interfacial alloying. In conjunction with the improved catalytic durability of the Au‐core@Pt‐based‐shell structure, it is reasonable to conclude that it is the subsurface segregated Au atoms rather than interfacial interaction that boosts the catalytic durability of Au‐core/Pt‐based‐shell structured catalysts towards oxygen reduction reaction. More importantly, by constructing Au‐core@Co‐interlayer@PtCoAu‐shell multilayer structure, the specific (1.730 mA cm−2) and mass (0.692 A mg−1Pt) activities are enhanced 7‐ and 4‐ fold relative to the commercial Pt/C. After 10 000 cycles of accelerated durability test, the mass activity loss for the multilayered catalyst is as low as 6.14% while the loss exceeds 35% for the commercial Pt/C catalyst. The improved catalytic performance of the Au@Co@PtCoAu multilayer structure can be ascribed to the finely modulated electronic structure and the compensated composition loss owing to the delicate structure and composition profile design.
PtAuCo‐shell‐based structures are achieved either by growth PtCo on Au nanoparticles or on Au@Co core–shell structures, demonstrating the outward segregation behavior of Au. The incorporation of Au improves the catalytic durability towards oxygen reduction reaction. The composition distribution profile illustrates that it is the subsurface segregated Au atoms rather than interfacial interaction boosts the catalytic durability of Au‐core/Pt‐based‐shell structures.
The effects of dark matter annihilation on the evolution of the intergalactic medium (IGM) in the early Universe will be more important if the dark matter structure is more concentrated. Ultracompact ...minihaloes (UCMHs), which formed through dark matter accretion on to primordial black holes (PBHs) or an initial dark matter overdensity produced by a primordial density perturbation, provide a new type of compact dark matter structure to ionize and heat the IGM after matter-radiation equality z
eq, which is much earlier than the formation of the first cosmological dark halo structure and later the first stars. We show that the dark matter annihilation density contributed by UCMHs can completely dominate over the homogeneous dark matter annihilation background, even for a tiny UCMH fraction f
UCMH=ΩUCMH(z
eq)/ΩDM≥ 10−15(1 +z)2(m
χ
c
2/100 GeV)−2/3 with a standard thermal-relic dark matter annihilation cross-section, and can provide a new gamma-ray background in the early Universe. UCMH annihilation becomes important to IGM evolution for approximately f
UCMH > 10−6(m
χ
c
2/100 GeV). The IGM ionization fraction x
ion and gas temperature T
m can be increased from the recombination residual x
ion∼ 10−4 and adiabatically cooling T
m∝ (1 +z)2 in the absence of energy injection, to a maximum value of x
ion∼ 0.1 and T
m∼ 5000 K at z≥ 10 for the upper bound on UCMH abundance constrained by the cosmic microwave background optical depth.
A small fraction of UCMHs are seeded by PBHs. The X-ray emission from gas accretion on to PBHs may totally dominate over dark matter annihilation, and may become the main cosmic ionization source for a PBH abundance f
PBH=ΩPBH/ΩDM≫ 10−11 (10−12) with PBH mass M
PBH∼ 10−6 M⊙ (102 M⊙). However, the constraints on gas accretion rate and X-ray absorption by baryon accumulation within UCMHs, together with accretion feedback, show that X-ray emission can only be a promising source much later than UCMH annihilation at z < z
m≪ 1000, where z
m depends on the PBH masses, their host UCMHs and the dark matter particles. Also, UCMH radiation including both annihilation and X-ray emission can significantly suppress the low-mass first baryonic structure formation. The effects of UCMH radiation on baryonic structure evolution are quite small as regards the gas temperature after virialization, but more significant in enhancing gas chemical quantities such as the ionization fraction and molecular hydrogen abundance in baryonic objects.
Dysregulation of circular RNAs (circRNAs) plays an important role in the development of gastric cancer; thus, revealing the biological and molecular mechanisms of abnormally expressed circRNAs is ...critical for identifying novel therapeutic targets in gastric cancer.
A circRNA microarray was performed to identify differentially expressed circRNAs between primary and distant metastatic tissues and between gastric cancer tissues sensitive or resistant to anti-programmed cell death 1 (PD-1) therapy. The expression of circRNA discs large homolog 1 (DLG1) was determined in a larger cohort of primary and distant metastatic gastric cancer tissues. The role of circDLG1 in gastric cancer progression was evaluated both in vivo and in vitro, and the effect of circDLG1 on the antitumor activity of anti-PD-1 was evaluated in vivo. The interaction between circDLG1 and miR-141-3p was assessed by RNA immunoprecipitation and luciferase assays.
circDLG1 was significantly upregulated in distant metastatic lesions and gastric cancer tissues resistant to anti-PD-1 therapy and was associated with an aggressive tumor phenotype and adverse prognosis in gastric cancer patients treated with anti-PD-1 therapy. Ectopic circDLG1 expression promoted the proliferation, migration, invasion, and immune evasion of gastric cancer cells. Mechanistically, circDLG1 interacted with miR-141-3p and acted as a miRNA sponge to increase the expression of CXCL12, which promoted gastric cancer progression and resistance to anti-PD-1-based therapy.
Overall, our findings demonstrate how circDLG1 promotes gastric cancer cell proliferation, migration, invasion and immune evasion and provide a new perspective on the role of circRNAs during gastric cancer progression.
Metallic lithium affords the highest theoretical capacity and lowest electrochemical potential and is viewed as a leading contender as an anode for high-energy-density rechargeable batteries. ...However, the poor wettability of molten lithium does not allow it to spread across the surface of lithiophobic substrates, hindering the production and application of this anode. Here we report a general chemical strategy to overcome this dilemma by reacting molten lithium with functional organic coatings or elemental additives. The Gibbs formation energy and newly formed chemical bonds are found to be the governing factor for the wetting behavior. As a result of the improved wettability, a series of ultrathin lithium of 10-20 μm thick is obtained together with impressive electrochemical performance in lithium metal batteries. These findings provide an overall guide for tuning the wettability of molten lithium and offer an affordable strategy for the large-scale production of ultrathin lithium, and could be further extended to other alkali metals, such as sodium and potassium.
High dietary fructose is a major contributor to insulin resistance and metabolic syndrome, disturbing tissue and organ functions. Fructose is mainly absorbed into systemic circulation by glucose ...transporter 2 (GLUT2) and GLUT5, and metabolized in liver to produce glucose, lactate, triglyceride (TG), free fatty acid (FFA), uric acid (UA) and methylglyoxal (MG). Its extrahepatic absorption and metabolism also take place. High levels of these metabolites are the direct dangerous factors. During fructose metabolism, ATP depletion occurs and induces oxidative stress and inflammatory response, disturbing functions of local tissues and organs to overproduce inflammatory cytokine, adiponectin, leptin and endotoxin, which act as indirect dangerous factors. Fructose and its metabolites directly and/or indirectly cause oxidative stress, chronic inflammation, endothelial dysfunction, autophagy and increased intestinal permeability, and then further aggravate the metabolic syndrome with tissue and organ dysfunctions. Therefore, this review addresses fructose-induced metabolic syndrome, and the disturbance effects of direct and/or indirect dangerous factors on the functions of liver, adipose, pancreas islet, skeletal muscle, kidney, heart, brain and small intestine. It is important to find the potential correlations between direct and/or indirect risk factors and healthy problems under excess dietary fructose consumption.
•Convolutional block attention module is included in the proposed model.•The proposed multiple-input end-to-end model can handle CCT and CXR images simultaneously.•Multiple-way data augmentation is ...employed to overcome overfitting problem.•The proposed model gives more accurate performances than individual modality.•The proposed model offers better performances than state-of-the-art approaches.
COVID-19 has caused 3.34m deaths till 13/May/2021. It is now still causing confirmed cases and ongoing deaths every day.
This study investigated whether fusing chest CT with chest X-ray can help improve the AI's diagnosis performance. Data harmonization is employed to make a homogeneous dataset. We create an end-to-end multiple-input deep convolutional attention network (MIDCAN) by using the convolutional block attention module (CBAM). One input of our model receives 3D chest CT image, and other input receives 2D X-ray image. Besides, multiple-way data augmentation is used to generate fake data on training set. Grad-CAM is used to give explainable heatmap.
The proposed MIDCAN achieves a sensitivity of 98.10±1.88%, a specificity of 97.95±2.26%, and an accuracy of 98.02±1.35%.
Our MIDCAN method provides better results than 8 state-of-the-art approaches. We demonstrate the using multiple modalities can achieve better results than individual modality. Also, we demonstrate that CBAM can help improve the diagnosis performance.
The photocatalytic reduction of CO2 to energy carriers has emerged as one of the most promising strategies to alleviate the energy crisis and CO2 pollution, for which the development of catalyst was ...considered as the determining factor for the accomplishment of this conversion process. In this study, three stable and isostructural metal–organic frameworks (denoted as MOF-Ni, MOF-Co, and MOF-Cu) have been synthesized and used as heterogeneous catalysts in photocatalytic CO2 reduction reaction (CO2RR). It is worth noting that the MOF-Ni exhibited very high selectivity of 97.7% for photoreducing CO2 to CO, which has exceeded most of the reported MOF-based catalysts in the field. Significantly, the MOFs associated with a monometallic catalytic center offer a simple and precise structural model which allows us to understand more definitively the specific effects of different metal-ion species on photoreduction of CO2 as well as the reactive mechanism.
Near‐infrared II (NIR‐II) imaging at 1100–1700 nm shows great promise for medical diagnosis related to blood vessels because it possesses deep penetration and high resolution in biological tissue. ...Unfortunately, currently available NIR‐II fluorophores exhibit slow excretion and low brightness, which prevents their potential medical applications. An atomic‐precision gold (Au) cluster with 25 gold atoms and 18 peptide ligands is presented. The Au25 clusters show emission at 1100–1350 nm and the fluorescence quantum yield is significantly increased by metal‐atom doping. Bright gold clusters can penetrate deep tissue and can be applied in in vivo brain vessel imaging and tumor metastasis. Time‐resolved brain blood‐flow imaging shows significant differences between healthy and injured mice with different brain diseases in vivo. High‐resolution imaging of cancer metastasis allows for the identification of the primary tumor, blood vessel, and lymphatic metastasis. In addition, gold clusters with NIR‐II fluorescence are used to monitor high‐resolution imaging of kidney at a depth of 0.61 cm, and the quantitative measurement shows 86% of the gold clusters are cleared from body without any acute or long‐term toxicity at a dose of 100 mg kg−1.
Near‐infrared II (NIR II) imaging at 1100–1700 nm with deep penetration and high resolution shows great promise for medical diagnosis. Ultrasmall gold clusters with 1100–1350 nm NIR IIa emission are developed and can penetrate the skull of mouse. In vivo cerebrovascular and tumor metastasis imaging show that they serve as an NIR‐II fluorescence agent with potential clinical transformation for medical diagnosis.
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