Direct Visualization of Dark Interlayer Exciton Transport in Moiré Superlattices.

Moiré superlattices have emerged as an unprecedented manipulation tool for engineering correlated quantum phenomena in van der Waals heterostructures. With moiré potentials as a naturally configurable solid-state that sustains high exciton density, interlayer excitons in transition metal dichalcogenide heterostructures are expected to achieve high-temperature exciton condensation. However, the exciton degeneracy state is usually optically inactive due to the finite momentum of interlayer excitons. Experimental observation of dark interlayer excitons in moiré potentials remains challenging. Here we directly visualize the dark interlayer exciton transport in WS2/h-BN/WSe2 heterostructures using femtosecond transient absorption microscopy. We observe a transition from classical free exciton gas to quantum degeneracy by imaging temperature-dependent exciton transport. Below a critical degeneracy temperature, exciton diffusion rates exhibit an accelerating downward trend, which can be explained well by a nonlinear quantum diffusion model. These results open the door to quantum information processing and high-precision metrology in moiré superlattices.

Bibliometric analysis of Traditional Chinese Medicine nanoparticles research from 2005 to 2023.

To gain a deeper understanding of the current status of research on Traditional Chinese Medicine (TCM) and nanoparticles, we conducted a bibliometric study. We conducted a literature search in the Web of Science (WOS) for publications related to TCM and nanoparticles from 1992 to 2023. The data, including countries of publication, research institutions, journals, citations, and keywords, were analyzed using the Bibliometrix R-4.0 software package. We performed an analysis to identify the co-occurrence of keywords in the documents including their titles and abstracts. From 2005 to 2023, a total of 309 publications were included, with an average annual growth rate of 4.25%. The majority of these publications were published in Q1 journals (72, 47.06%) and Q2 journals (45, 29.41%). Among the 309 publications, 22 articles (7.12%) had an impact factor greater than 10, while 78 articles (25.24%) had an impact factor greater than 5. The analysis of international collaboration networks revealed limited international cooperation, with most collaborations occurring between institutions in China, the United States, and Australia. These 309 publications involved a total of 438 research institutions, with Chinese research institutions being the most prolific contributors. In this study, a total of 309 publications were included, comprising 1142 author keywords and 1175 keywords plus. Factor analysis of the 1175 keywords plus revealed that they could be grouped into five categories: one category included terms such as "oxide" and "zinc," another category included terms like "lipid" and "acid," a third category included terms such as "improve" and "enhance," a fourth category included terms like "silica" and "mesoporous," and the fifth category included terms like "PLGA" and "immune." Research on nanoparticles in TCM has been gradually gaining popularity. Currently, most of the research in this field is conducted in China, with limited international collaboration. The majority of TCM nanoparticle research focuses on individual herbal compounds, while research on nanoparticle formulations of traditional herbal prescriptions is relatively scarce.

Unraveling the Synergistic Mechanism of Ir Species with Various Electron Densities over an Ir/ZSM-5 Catalyst Enables High-Efficiency NO Reduction by CO.

Selective catalytic reduction using CO as a reducing agent (CO-SCR) has exhibited its application potential in coal-fired, steel, and other industrial sectors. In comparison to NH3-SCR, CO-SCR can achieve synergistic control of CO and NO pollutants, making it a powerful denitrification technology that treats waste with waste. Unfortunately, the competitive adsorption of O2 and NO on CO-SCR catalysts inhibits efficient conversion of NOx under O2-containing conditions. In this work, we obtained two Ir sites with different electron densities, Ir1 single atoms in the oxidized Irδ+ state and Ir0 nanoparticles in the metallic state, by controlled pretreatment of the Ir/ZSM-5 catalyst with H2 at 200 °C. The coexistence of Ir1 single atoms and Ir0 nanoparticles on ZSM-5 creates a synergistic effect, which facilitates the reduction of NO through CO in the presence of O2, following the Langmuir-Hinshelwood mechanism. The ONNO dimer is formed on the Ir1 single atom sites and then spills over to the neighboring Ir0 nanoparticles for subsequent reduction to N2 by CO. Specifically, this tandem reaction enables 83% NO conversion and 100% CO conversion on an Ir-based catalyst at 250 °C under 3% O2.

Catalytic removal of gaseous pollutant NO using CO: Catalyst structure and reaction mechanism.

Carbon monoxide (CO) has recently been considered an ideal reducing agent to replace NH3 in selective catalytic reduction of NOx (NH3-SCR). This shift is particularly relevant in diesel engines, coal-fired industry, the iron and steel industry, of which generate substantial amounts of CO due to incomplete combustion. Developing high-performance catalysts remain a critical challenge for commercializing this technology. The active sites on catalyst surface play a crucial role in the various microscopic reaction steps of this reaction. This work provides a comprehensive overview and insights into the reaction mechanism of active sites on transition metal- and noble metal-based catalysts, including the types of intermediates and active sites, as well as the conversion mechanism of active molecules or atoms. In addition, the effects of factors such as O2, SO2, and alkali metals, on NO reduction by CO were discussed, and the prospects for catalyst design are proposed. It is hoped to provide theoretical guidance for the rational design of efficient CO selective catalytic denitration materials based on the structure-activity relations.

Anionic oxyl radical formed on CrVI-oxo anchored on the defect site of the UiO-66 node facilitates methane to methanol conversion.

The direct conversion of methane to methanol has attracted increasing interest due to abundant and low-cost natural gas resources. Herein, by anchoring Cr-oxo/-oxyhydroxides on UiO-66 metal-organic frameworks, we demonstrate that reactive anionic oxyl radicals can be formed by controlling the coordination environment based on the results of density functional theory calculations. The anionic oxyl radicals produced at the completely oxidized CrVI site acted as the active species for facile methane activation. The thermodynamically stable CrVI-oxo/-oxyhydroxides with the anionic oxyl radicals catalyze the activation of the methane C-H bond through a homolytic mechanism. An analysis of the results showed that the catalytic performance of the active oxyl species correlates with the reaction energy of methane activation and H adsorption energies. Following methanol formation, N2O can regenerate the active sites on the most stable CrVI oxyhydroxides, i.e., the Cr(O)4Hf species. The present study demonstrated that the anionic oxyl radicals formed on the anchored CrVI oxyhydroxides by tuning the coordination environment enabled facile methane activation and facilitated methanol production.

Correlation between the Properties of Surface Lattice Oxygen on NiO and Its Reactivity and Selectivity towards the Oxidative Dehydrogenation of Propane.

Modified NiO catalysts with controllable vacancies and dopants are promising for alkene production from oxidative dehydrogenation (ODH) of light alkanes, and a molecular understanding of the modification on elementary reaction steps would facilitate the design of highly efficient catalysts and catalytic processes. In this study, density functional theory (DFT) calculations was used to map out the complete reaction pathways of propane ODH on the NiO (100) surfaces with different modifiers. The results demonstrated that the presence of vacancies (O and Ni) and dopants (Li and Al) alters the electrophilicity of surface oxygen species, which in turn affects the reactivity towards C-H bond activation and the overall catalytic activity and selectivity. The strongly electrophilic O favors a radical mechanism for the first C-H activation on O followed by the second C-H activation on O-O site, whereas weak electrophilic O favors concerted C-H bond breaking over Ni-O site. The C-H bond activation proceeds through a late transition state, characterized by the almost completion of the O-H bond formation. Consequently, the adsorption energy of H adatom on O rather than p-band center or Bader charge of O has been identified to be an accurate descriptor to predict the activation barrier for C-H breaking (activity) as well as the difference between the activation barriers of propene and CH3 CCH3 (selectivity) of ODH.

Coupled oxygen desorption and structural reconstruction accompanying reduction of copper oxide.

Understanding structural transformation and phase transition accompanying reactions in a solid as a catalyst or oxygen carrier is important to the design and optimization of many catalytic or chemical looping reaction processes. Herein, we combined density functional theory calculation with the stochastic surface walking global optimization approach to track the structural transformation accompanying the reduction of CuO upon releasing oxygen. We then used machine learning (ML) methods to correlate the structural properties of CuOx with varying x. By decomposing a reduction step into oxygen detachment and structural reconstruction, we identified two types of pathways: (1) uniform reduction with minimal structural changes; (2) segregated reduction with significant reconstruction. The results of ML analysis showed that the most important feature is the radial distribution functions of Cu-O at a percentage of oxygen vacancy [C(OV)] < 50% and Cu-Cu at C(OV) > 50% for CuOx formation. These features reflect the underlying physicochemical origin, i.e., Cu-O breaking and Cu-Cu formation in the respective stage of reduction. Phase diagram analysis indicates that CuO will be reduced to Cu2O under a typical oxygen uncoupling condition. This work demonstrates the complexity of solid structural transformation and the potential of ML methods in studying solid state materials involved in many chemical processes.

The role and mechanism of noncoding RNAs in regulation of metabolic reprogramming in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer. Metabolic reprogramming is considered to be an important hallmark of cancer. Emerging studies have demonstrated that noncoding RNAs (ncRNAs) are closely associated with metabolic reprogramming of HCC. NcRNAs can directly regulate the expressions or functions of metabolic enzymes or indirectly regulate the metabolism of HCC cells through some vital signaling pathways. Until now, the mechanisms of HCC development and progression remain largely unclear, and understanding the regulatory mechanism of ncRNAs on metabolic reprogramming of HCC may provide an important basis for breakthrough progress in the treatment of HCC. In this review, we summarize the ncRNAs involved in regulating metabolic reprogramming of HCC. Specifically, the regulatory roles of ncRNAs in glucose, lipid and amino acid metabolism are elaborated. In addition, we discuss the molecular mechanism of ncRNAs in regulation of metabolic reprogramming and possible therapeutic strategies that target the metabolism of cancer cells by modulating the expressions of specific ncRNAs.

Research on Multi-View 3D Reconstruction Technology Based on SFM.

Multi-view 3D reconstruction technology is used to restore a 3D model of practical value or required objects from a group of images. This paper designs and implements a set of multi-view 3D reconstruction technology, adopts the fusion method of SIFT and SURF feature-point extraction results, increases the number of feature points, adds proportional constraints to improve the robustness of feature-point matching, and uses RANSAC to eliminate false matching. In the sparse reconstruction stage, the traditional incremental SFM algorithm takes a long time, but the accuracy is high; the traditional global SFM algorithm is fast, but its accuracy is low; aiming at the disadvantages of traditional SFM algorithm, this paper proposes a hybrid SFM algorithm, which avoids the problem of the long time consumption of incremental SFM and the problem of the low precision and poor robustness of global SFM; finally, the MVS algorithm of depth-map fusion is used to complete the dense reconstruction of objects, and the related algorithms are used to complete the surface reconstruction, which makes the reconstruction model more realistic.

Design, synthesis and antibacterial activity evaluation of pleuromutilin derivatives according to twin drug theory.

A series of novel pleuromutilin derivatives were designed and synthesized based on the twin drugs theory. Piperazinyl and thioether were used as the linkage to connect the pleuromutilin nuclear and sulfonamide to improve the biological activity and water solubility of derivatives. The in vitro antibacterial activities against drug-sensitive and drug-resistance bacteria were evaluated by agar dilution method. Most of the 25 compounds displayed excellent antibacterial activities against drug-sensitive bacteria, particularly, five compounds (9, 10, 11, 14a and 14b) exerted the excellent antibacterial activities against drug-resistance bacteria.

Design, synthesis and antibacterial activities of pleuromutilin derivatives.

We described the design, synthesis and antimicrobial activities of novel pleuromutilin derivatives with substituted piperazine substrate. Minimum inhibitory concentration (MIC) was used to evaluate the activity of the derivatives against six bacteria in vitro, and compound 8 was potent against Staphylococcus aureus and Staphylococcus epidermidis with the MIC value of 0.0625 µg/ml. 10a and 10 b showed similar activity to positive control drugs (tiamulin, erythromycin) against S. aureus with the MIC value of 0.125 µg/ml. The binding mode of compound 8 and tiamulin to the ribosome pocket showed the correlation between binding parameters and the antibacterial activity, and more bonds and stronger combination could effectively enhance the activity of compounds.[Formula: see text].

Cardioprotective effect of rosmarinic acid against myocardial ischaemia/reperfusion injury via suppression of the NF-κB inflammatory signalling pathway and ROS production in mice.

CONTEXT: Rosmarinic acid (RosA), a natural poly-phenolic compound isolated from a variety of Labiatae herbs, has been reported to have a range of biological effects. OBJECTIVE: To investigate the cardioprotective effects of RosA against myocardial ischaemia/reperfusion (I/R) injury. MATERIALS AND METHODS: Male C57BL/6J mice were given RosA (100 mg/kg) via intragastric administration. After 1 week of administration, the mice were subjected to 30 min/24 h myocardial I/R injury. The mice were randomly subdivided into 4 groups: Vehicle, RosA, Vehicle + I/R, and RosA + I/R. Infarct size (IS), cardiac function (including EF, FS), histopathology, serum enzyme activities, ROS changes, cis aconitase (ACO) activity, and specific mRNA and protein levels were assessed in vivo. HL-1 cells were pre-treated with or without RosA (50 µM), followed by stimulation with 9 h/6 h of oxygen and glucose deprivation/re-oxygenation (OGD/R). The cells were randomly subdivided into 4 groups: Vehicle, RosA, Vehicle + OGD/R, and RosA + OGD/R. Lactate dehydrogenase (LDH) levels, ACO activity, ROS changes and protein levels were measured in vitro. RESULTS: Treatment with RosA reduced the following indicators in vivo (p < 0.05): (1) IS (14.5%); (2) EF (-23.4%) and FS (-18.4%); (3) the myocardial injury enzymes CK-MB (20.8 ng/mL) and cTnI (7.7 ng/mL); (4) DHE-ROS: (94.1%); (5) ACO activity (-2.1 mU/mg protein); (6) ogdh mRNA level (122.9%); and (7) OGDH protein level (69.9%). Moreover, treatment with RosA attenuated the following indicators in vitro (p < 0.05): (1) LDH level (191 U/L); (2) DHE-ROS: (165.2%); (3) ACO activity (-3.2 mU/mg protein); (4) ogdh mRNA level (70.0%); and (5) OGDH (110.1%), p-IκB-a (56.8%), and p-NF-κB (57.7%) protein levels. CONCLUSIONS: RosA has the potential to treat myocardial I/R injury with potential application in the clinic.

Superlubricity between a silicon tip and graphite enabled by the nanolithography-assisted nanoflakes tribo-transfer.

Superlubricity between a cone-shaped (sharp) silicon tip and graphite remains a challenge in the nanotribology field. In this paper, an efficient method of achieving superlubricity between a cone-shaped silicon tip and graphite was proposed. Graphite nanoflakes were transferred onto the silicon tip by repeatedly rubbing against the scratches produced by nanolithography on a graphite surface. The superlubricity between the graphite nanoflakes-wrapped tip and highly oriented pyrolytic graphite (HOPG) was attained, and the friction coefficient was reduced to 0.0007. At low normal loads, the frictional force was small and showed a strong correlation with the sliding angle, but as the normal load increased, this dependence gradually decreased. It was firstly found that the transferred graphite nanoflakes on the contact zone of the silicon tip could be transformed into amorphous carbon layers induced by the shear force and high pressure during the superlubricity test process.

Clinical features and factors leading to early recurrence of intussusception after saline reduction.

OBJECTIVE: To investigate the clinical characteristics of early recurrent intussusception after ultrasound-guided saline reduction, and to explore the factors leading to early recurrence. METHODS: The retrospective observational case-control study was conducted at Weifang People's Hospital, Shandong, China, and comprised data from January 2015 to December 2017 related to paediatric intussusception patients aged 0-12 years who underwent ultrasound-guided saline enema reduction. The patients were divided into two recurrent and non-recurrent groups. Clinical characteristics of the patients with early recurrence were analysed. Factors compared between the groups were gender, age, onset season, onset-to-treatment time interval, blood in stool, fever, diarrhoea, abdominal pain and vomiting, weight and pathology. Data was analysed using SPSS 22. RESULTS: Of the 672 subjects, 86(13%) were patient with early recurrence while 586(87%) had no early recurrence and acted as controls. Among the patients, 70(81.4%) were aged 6-36 months. In 52(60.5%) patients, recurrence was once, and in 23(26.7%) twice. There were 141 episodes of intussusception; 24(17%) occurring in <12 hours, 85(60.2%) in 12-24 hours. Also, 5(6%) patients required surgery for reduction. Compared to the controls, the second quarter, heavier body weight and pathology were the factors leading to early recurrence of intussusceptions (p<0.05). CONCLUSIONS: The second quarter, heavier body weight and pathological leading points were found to be factors leading to early recurrent intussusception.

One-step preparation of polyimide-inlaid amine-rich porous organic block copolymer for efficient removal of chlorophenols from aqueous solution.

A novel polyimide-inlaid amine-rich porous organic block copolymer (PI-b-ARPOP) was prepared via one-step polymerization by using different molar ratios of melamine (MA)/terephthalaldehyde (TA)/pyromellitic dianhydride (PMDA), at molar ratios of 4/3/1, 4/2/2 and 4/1/3. The copolymer contained both aminal groups belonging to ARPOP and imide groups belonging to PI, and the bonding styles of the monomers and growth orientations of the polymeric chains were diversiform, forming an excellent porous structure. Notably, MA/TA/PMDA (4/2/2) had a surface area and pore volume of 487.27 m2/g and 1.169 cm3/g, respectively. The adsorption performance of the materials towards 2,4-dichlorophenol (2,4-DCP) in ultra-pure water was systematically studied. The pH value of 7 was optimal in aqueous solution. Na+ and Cl- ions did not negatively affect the adsorption process, while humic acid (HA) slightly decreased the capacity. The equilibrium time was 40 sec, and the maximum adsorption capacity reached 282.49 mg/g at 298 K. The removal process was endothermic and spontaneous, and the copolymer could maintain its porous structure and consistent performance after regeneration by treatment with alkali. Moreover, to further assess the practical applicability of the material, the adsorption performance towards 2,4-DCP in river water was also investigated. This paper demonstrated that the PI-b-ARPOP can be an efficient and practical adsorbent to remove chlorophenols from aqueous solution.

Synthesis and Biological Evaluation of Novel Thioether Pleuromutilin Derivatives.

To develop new pleuromutilin derivatives as veterinary antibiotic medicines, we designed and synthesized a series of new thioether pleuromutilin derivatives possessing acylthiazolyl moiety based on previously designed derivatives. The antibacterial properties of the prepared pleuromutilin derivatives were assessed in vitro by the broth dilution method against five kinds of bacteria and the mycoplasma Mycoplasma gallisepticum (MG). All of the tested compounds displayed moderate to good antibacterial activity to methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-sensitive Staphylococcus epidermidis (MSSE), methicillin-resistant S. aureus (MRSA), Streptococcus agalactiae (S. aga) and MG. However, the activity to Pyogeniccoccus (Pyogens) was generally poor. Compounds 13i and l showed potent antibacterial activity against MSSE and MRSA which are better than that of valnemulin. The structural modification for pleuromutilin affected the antibacterial activity. Amino substituents in the benzene ring can effectively improve activity. Compared with the analogue 13a that possesses unsubstitution benzoyl group, the nitro, methoxy, hydroxy and dichloro substituent contributed little to antibacterial activity. Increasing a methylene between benzene moiety and carbonyl group decreased the bioactivity of derivative. The analogues that obtained by the reaction of amino acids and intermediate 9 showed moderate activity.

110 W all-fiber picosecond master oscillator power amplifier based on large-core-diameter ytterbium-doped fiber.

We demonstrate an all-fiber picosecond fiber laser in a master oscillator power amplifier configuration. The seed source is a soliton-type passively mode-locked Yb-doped fiber laser by a semiconductor saturable absorber mirror and chirped fiber Bragg grating. The pulse width of the seed laser is 4.5 ps with a repetition rate of 15 MHz. A highly doped active fiber with a large core diameter (50 µm) is employed to boost the average power of the seed pulses to 117 W with 11 ps pulse width and 709 kW peak power. The corresponding output beam quality factor at maximum output power is 3.7. The all-fiber construction of the whole laser system enables compact size and robust operation.

Synthesis and Antibacterial Activity of Novel Pleuromutilin Derivatives.

In this study we describe the design, synthesis, and antibacterial activity of novel pleuromutilin analogs. A series of new compounds containing piperazine and alkylamino or arylamino groups was synthesized. The new compounds were characterized via (1)H-NMR, (13)C-NMR, Fourier transform (FT)-IR and MS, and were further evaluated for their in vitro activity against seven Gram-positive, and one Gram-negative, pathogens. Antibacterial data revealed that all compounds exhibited moderate to good antibacterial activities against sensitive Gram-positive pathogens. Specifically, 9d displayed the best activity: its activity to Staphylococcus aureus (ATCC25923) is 0.125 µg/mL, which is equal to the control compound tiamulin. The antibacterial activities of 9d to Streptococcus suis (minimum inhibitory concentration (MIC) of 2 µg/mL), Streptococcus agalactiae (MIC of 0.5 µg/mL), and Streptococcus dysgalactiae (MIC of 0.5 µg/mL) were also excellent compared with the control drug erythromycin (MIC of >128 µg/mL). The binding modes of these compounds with active sites were calculated using the programs of Molecular Operating Environment (MOE) and Pymol.

Effectiveness and safety of tendon-bone-setting in postpartum women with sacroiliac joint pain: A retrospective multicenter study.

Sacroiliac joint (SIJ) pain leads to abnormal joint loading, and is a key risk factor for joint degeneration. This study aimed to determine the effect of tendon-bone-setting on postpartum women with SIJ pain. Multicenter retrospective review of medical records and electroencephalography reports in 10 academic medical centers. 328 postpartum women with sacroiliac joint pain were divided into 2 groups according to the methods of therapy. Group (A) (n = 203) received acupuncture combined with tendon-bone-setting for twenty days, whereas group (B) (n = 125) received only the same acupuncture for twenty days. The outcome measures were the mean values of numeric pain rating scale (NPRS), present pain intensity (PPI) scale, visual analog scale (VAS) and Japanese orthopedic association (JOA) score to evaluate pain intensity, oswestry disability index (ODI), quebec back pain disability scale (QBPDS), active straight leg raise (ASLR) and back pain function scale (BPFS) to evaluate the functional disability, pressure pain thresholds (PPT) at 5 chosen points in the sacroiliac joint region to assess pain sensitivity. All of them were evaluated before and after treatment. The effectiveness from short to long term, as well as safety was assessed in this study. A comparison of the 2 groups after treatment showed statistically significant increases in the mean values of BPFS, JOA and PPT at the 5 chosen points (P < .05), as well as significant reductions in the scores of QBPDS, ODI, ASLR, NPRS, VAS and PPI (P < .05) in favor of group (B). In addition, after treatment for 2 weeks, the considered effective rate in the group (A) was significantly higher than that in the group (B) (P < .05). Also, the cumulative incidence of pain relief at 24 months in the group (A) was greater compared with the group (B) as determined by Kaplan-Meier analysis (P < .05). Interestingly, none serious adverse event for the participants was reported. Tendon-Bone-Setting is effective and safe in treating sacroiliac joint pain for the postpartum women patients in the short and long terms through decreasing pain sensitivity and intensity, as well as improving functional ability.

Design, synthesis, and antibacterial activity of pleuromutilin derivatives.

This paper reports the design, synthesis, and antibacterial activity study of pleuromutilin derivatives with 2-methyl-4-nitroaniline and 2-methoxy-4-nitroaniline side chains at the C22 position. The structures of the new compounds were characterized by 1H-NMR, 13C-NMR and HRMS. The inhibitory activity of the compounds against MSSA, pyogeniccoccus, streptococcus, and MRSA strains was determined using the micro broth dilution method. The results showed that the compounds exhibited certain activity against Gram-positive bacteria, among which compounds A8a, A8b, A8c, A8d, and A7 demonstrated superior antibacterial activity against MSSA, MRSA, and pyogeniccoccus compared to tiamulin, although the derivatives showed lower antibacterial activity against streptococcus compared to the control drug. Based on the favorable in vitro activity of A8c, the time-kill kinetics against MRSA were evaluated, revealing that compound A8c could inhibit bacterial proliferation in a concentration-dependent manner.