Two-Dimensional Conjugated Metal-Organic Frameworks with a Ring-in-Ring Topology and High Electrical Conductance.

Electrically conducting two-dimensional (2D) metal-organic frameworks (MOFs) have garnered significant interest due to their remarkable structural tunability and outstanding electrical properties. However, the design and synthesis of high-performance materials face challenges due to the limited availability of specific ligands and pore structures. In this study, we have employed a novel highly branched D3h symmetrical planar conjugated ligand, dodechydroxylhexabenzotrinaphthylene (DHHBTN) to fabricate a series of 2D conductive MOFs, named M-DHHBTN (M = Co, Ni, and Cu). This new family of MOFs offers two distinct types of pores, elevating the structural complexity of 2D conductive MOFs to a more advanced level. The intricate tessellation patterns of the M-DHHBTN are elucidated through comprehensive analyses involving powder X-ray diffraction, theoretical simulations, and high-resolution transmission electron microscope. Optical-pump terahertz-probe spectroscopic measurements unveiled carrier mobility in DHHBTN-based 2D MOFs spanning from 0.69 to 3.10 cm2 V-1 s-1. Among M-DHHBTN famility, Cu-DHHBTN displayed high electrical conductivity reaching 0.21 S cm-1 at 298 K with thermal activation behavior. This work leverages the "branched conjugation" of the ligand to encode heteroporosity into highly conductive 2D MOFs, underscoring the significant potential of heterogeneous double-pore structures for future applications.

Electrochemical E-Selective Semireductive Dicarboxylation of Aryl Alkynes with CO2.

Herein, we report an electrochemical protocol for the dicarboxylation of aryl alkynes using CO2. With a graphite rod as the cathode and Al as the sacrificial anode, a series of valuable butenedioic acids are obtained in moderate to excellent yields with an E/Z ratio up to 50:1. This method features high E-selectivity, high step and atom economy, easy scalability, and a nice substrate scope, which renders it appealing for promising applications in organic synthesis and materials chemistry.

Gas-Induced Electrical and Magnetic Modulation of Two-Dimensional Conductive Metal-Organic Framework.

Controlled modulation of electronic and magnetic properties in stimuli-responsive materials provides valuable insights for the design of magnetoelectric or multiferroic devices. This paper demonstrates the modulation of electrical and magnetic properties of a semiconductive, paramagnetic metal-organic framework (MOF) Cu3(C6O6)2 with small gaseous molecules, NH3, H2S, and NO. This study merges chemiresistive and magnetic tests to reveal that the MOF undergoes simultaneous changes in electrical conductance and magnetization that are uniquely modulated by each gas. The features of response, including direction, magnitude, and kinetics, are modulated by the physicochemical properties of the gaseous molecules. This study advances the design of multifunctional materials capable of undergoing simultaneous changes in electrical and magnetic properties in response to chemical stimuli.

Turning on Singlet Oxygen Generation by Outer-Sphere Microenvironment Modulation in Porphyrinic Covalent Organic Frameworks for Photocatalytic Oxidation.

Singlet oxygen (1 O2 ) is ubiquitously involved in various photocatalytic oxidation reactions; however, efficient and selective production of 1 O2 is still challenging. Herein, we reported the synthesis of nickel porphyrin-based covalent organic frameworks (COFs) incorporating functional groups with different electron-donating/-withdrawing features on their pore walls. These functional groups established a dedicated outer-sphere microenvironment surrounding the Ni catalytic center that tunes the activity of the COFs for 1 O2 -mediated thioether oxidation. With the increase of the electron-donating ability of functional groups, the modulated outer-sphere microenvironment turns on the catalytic activity from a yield of nearly zero by the cyano group functionalized COF to an excellent yield of 98 % by the methoxy group functionalized one. Electronic property investigation and density-functional theory (DFT) calculations suggested that the distinct excitonic behaviors attributed to the diverse band energy levels and orbital compositions are responsible for the different activities. This study represents the first regulation of generating reactive oxygen species (ROS) based on the strategy of outer-sphere microenvironment modulation in COFs.

Dynamics of Electron Transfer in CdS Photocatalysts Decorated with Various Noble Metals.

To address charge recombination in photocatalysis, the prevalent approach involves the use of noble metal cocatalysts. However, the precise factors influencing this performance variability based on cocatalyst selection have remained elusive. In this study, CdS hollow spheres loaded with distinct noble metal nanoparticles (Pt, Au, and Ru) are investigated by femtosecond transient absorption (fs-TA) spectroscopy. A more pronounced internal electric field leads to the creation of a larger Schottky barrier, with the order Pt-CdS > Au-CdS > Ru-CdS. Owing to these varying Schottky barrier heights, the interface electron transfer rate (Ke ) and efficiency (ηe ) of metal-CdS in acetonitrile (ACN) exhibit the following trend: Ru-CdS > Au-CdS > Pt-CdS. However, the trends of Ke and ηe for metal-CdS in water are different (Ru-CdS > Pt-CdS > Au-CdS) due to the influence of water, leading to the consumption of photogenerated electrons and affecting the metal/CdS interface state. Although Ru-CdS displays the highest Ke and ηe , its overall photocatalytic performance, particularly in H2 production, lags behind that of Pt-CdS due to the electron backflow from Ru to CdS. This work offers a fresh perspective on the origin of performance differences and provides valuable insights for cocatalyst design and construction.

Analysis of the clinical characteristics in 18 patients with novel coronavirus pneumonia: Observational study.

The aim of the present study was to analyze the clinical features, treatments, and short-term prognoses of 18 patients with novel coronavirus pneumonia (NCP) in order to provide reference for further clinical prevention and control of the epidemic. From January 29 to February 29, 2020, data from 18 patients with NCP who were positive for the 2019 novel coronavirus nucleic acid test were collected, and their clinical manifestations, laboratory tests, imaging features, and treatment protocols were analyzed retrospectively. From among the 18 patients with NCP, 9 (50%) were imported cases and 9 (50%) had contact histories with confirmed adult patients. Clinical classification was mainly of the normal type (16 cases, 88.9%). Fever and cough were common clinical symptoms, and the main laboratory indices were lymphocytopenia and leukocytopenia. The main imaging findings yielded ground-glass opacity in 12 cases (66.7%) and patchy opacity in 9 cases (50%). All 18 patients were treated with antiviral therapy and targeted treatment in accordance with their symptoms, returned negative nucleic acid tests (9-23 days) after their treatment, and were cured and discharged by March 5, 2020. During the early stages in Deyang, most patients with NCP were input cases; in the later stages, the main route of infection was close contact within the family. Close contact history in epidemiology, nucleic acid detection, and chest imaging were important references for diagnosis. Antiviral therapy resulted in good therapeutic effects. Adopting multi-departmental consultation and remote consultation in combination with traditional Chinese medicine treatment and psychological counseling may result in a good short-term prognosis.

Conductive Covalent Organic Frameworks of Polymetallophthalocyanines as a Tunable Platform for Electrocatalysis.

Developing an electrocatalyst platform that can control the interplay among activity, selectivity, and stability at atomic precision remains a grand challenge. Here, we have synthesized highly crystalline polymetallophthalocyanines (pMPcs, M = Fe, Co, Ni, and Cu) through the annulation of tetracyanobenzene in the presence of transition metals. The conjugated, conductive, and stable backbones with precisely installed metal sites render pMPcs a unique platform in electrochemical catalysis, where tunability emerges from long-range interactions. The construction of pCoNiPc with a Co and Ni dual-site integrates the advantageous features of pCoPc and pNiPc in electrocatalytic CO2 reduction through electronic communication of the dual-site with an unprecedented long atomic separation of ≥14 chemical bonds. This integration provides excellent activity (current density, j = -16.0 and -100 mA cm-2 in H-type and flow cell, respectively), selectivity (CO Faraday efficiency, FECO = 94%), and stability (>10 h), making it one of the best-performing reticular materials.

Public acceptance of residential photovoltaic installation: A case study in China.

Residential photovoltaics (PV) presents an effective means of achieving low-carbon development, owing to its installation flexibility and resource-saving properties. To explore the residents' behavioral intentions to purchase and install residential PV systems, this study collected 1424 samples and analyze the impact of different policies on residents' adoption of residential PV using the theory of TPB and the Partial Least Squares Structural Equation Model (PLS-SEM). The main conclusions are summarized as follows: (1) Bungalow residents exhibit a stronger inclination to install residential PV than building residents. (2) Perceived reward (PR) affects installation intention (II) more than perceived guide (PG) among bungalow residents. (3) Both PR and PG indirectly affect II through Perceived behavioral control (PBC) among bungalow residents. Economic policies, represented by PR, are likely to have more substantial indirect effects than propaganda and guidance policies. The findings suggest that China's recent residential PV installation policies should increase users' trust and guide the future decline of subsidy policy.

Turning on Asymmetric Catalysis of Achiral Metal-Organic Frameworks by Imparting Chiral Microenvironment.

The development of heterogeneous asymmetric catalysts has attracted increasing interest in synthetic chemistry but mostly relies on the immobilization of homogeneous chiral catalysts. Herein, a series of chiral metal-organic frameworks (MOFs) have been fabricated by anchoring similar chiral hydroxylated molecules (catalytically inactive) with different lengths onto Zr-oxo clusters in achiral PCN-222(Cu). The resulting chiral MOFs exhibit regulated enantioselectivity up to 83 % ee in the asymmetric ring-opening of cyclohexene oxide. The chiral molecules furnished onto the catalytic Lewis sites in the MOF create multilevel microenvironment, including the hydrogen interaction between the substrate and the chiral -OH group, the steric hindrance endowed by the benzene ring on the chiral molecules, and the proximity between the catalytic sites and chiral molecules confined in the MOF pores, which play crucial roles and synergistically promote chiral catalysis. This work nicely achieves heterogeneous enantioselective catalysis by chiral microenvironment modulation around Lewis acid sites.

Bioinspired microenvironment modulation of metal-organic framework-based catalysts for selective methane oxidation.

Inspiration from natural enzymes enabling creationary catalyst design is appealing yet remains extremely challenging for selective methane (CH4) oxidation. This study presents the construction of a biomimetic catalyst platform for CH4 oxidation, which is constructed by incorporating Fe-porphyrin into a robust metal-organic framework, UiO-66, furnished with saturated monocarboxylic fatty acid bearing different long alkyl chains. The catalysts demonstrate the high efficiency in the CH4 to methanol (CH3OH) conversion at 50 °C. Moreover, the selectivity to CH3OH can be effectively regulated and promoted through a fine-tuned microenvironment by hydrophobic modification around the Fe-porphyrin. The long-chain fatty acids anchored on the Zr-oxo cluster of UiO-66 can not only tune the electronic state of the Fe sites to improve CH4 adsorption, but also restrict the amount of H2O2 around the Fe sites to reduce the overoxidation. This behavior resembles the microenvironment regulation in methane monooxygenase, resulting in high CH3OH selectivity.

Dual Microenvironment Modulation of Pd Nanoparticles in Covalent Organic Frameworks for Semihydrogenation of Alkynes.

The chemical microenvironment modulation of metal nanoparticles (NPs) holds promise for tackling the long-lasting challenge of the trade-off effect between activity and selectivity in catalysis. Herein, ultrafine PdCu2 NPs incorporated into covalent organic frameworks (COFs) with diverse groups on their pore walls have been fabricated for the semihydrogenation of alkynes. The Cu species, as the primary microenvironment of Pd active sites, greatly improves the selectivity. The functional groups as the secondary microenvironment around PdCu2 NPs effectively regulate the activity, in which PdCu2 NPs encapsulated in the COF bearing -CH3 groups exhibit the highest activity with >99 % conversion and 97 % selectivity. Both experimental and calculation results suggest that the functional group affects the electron-donating ability of the COFs, which successively impacts the charge transfer between COFs and Pd sites, giving rise to a modulated Pd electronic state and excellent catalytic performance.

ANFIS-based forming limit prediction of stainless steel 316 sheet metals.

Effect of microstructure on the formability of the stainless sheet metals is a major concern for engineers in sheet industries. In the case of austenitic steels, existence of strain-induced martensite ([Formula: see text]-martensite) in their micro structure causes considerable hardening and formability reduction. In the present study, we aim to evaluate the formability of AISI 316 steels with different intensities of martensite via experimental and artificial intelligence methods. In the first step, AISI 316 grade steels with 2 mm initial thicknesses are annealed and cold rolled to various thicknesses. Subsequently, the relative area of strain-induced martensite are measured using metallography tests. Formability of the rolled sheets are determined using hemisphere punch test to obtain forming limit diagrams (FLDs). The data obtained from experiments were further utilized to train and validate an artificial neural fuzzy interfere system (ANFIS). After training the ANFIS, predicted major strains by the neural network are compared to a new set experimental results. The results indicate that cold rolling has unfavorable effects on the formability of this type of stainless steels while significantly strengthens the sheets. Moreover, the ANFIS exhibits satisfactory results in comparison to the experimental measurements.

Resource exergy analysis of the Chinese society in 2017.

China has made huge efforts to increase the efficiency of its resources and change its resource-intensive economic trajectory. A question which should be raised is whether the impacts of such shifts can be measured. Exergy analysis provides a unified method of ecological diagnosis of resource allocation and metabolism in social systems from a biophysical perspective. This paper explores the resource utilization pattern within Chinese society by employing an exergy-based accounting method. Nationally total resource consumption amounted to 153.7 EJ in 2017, and non-biological resources reached 137.1 EJ. China's resource self-sufficiency rate was revealed as 79.1%. After China experienced a transition period with a medium-high economic growth rate, the total net resource input into Chinese society marked an increase of around 1% from 2012 to 2017. The per capita resource consumption dropped from 112.0 GJ in 2012 to 110.6 GJ in 2017. The proportion of resource exergy consumption in the tertiary sector was upregulated from 10.0% in 2012 to 17.6% in 2017. To be specific, the exergy conversion efficiency of the domestic sector rose from 1.3% in 2012 to 20.6% in 2017. The results confirm that the resource exergy utilization structures and the conversion efficiencies of the main social sectors in China's economic transition period were significantly optimized towards a more sustainable future. A reasonable analysis of the resource exergy utilization pattern provides a solid reference for assessing the comprehensive effect of the changed development speed, industrial structure, and driving force of a developing society.

Fabrication of Multifunctional Electronic Textiles Using Oxidative Restructuring of Copper into a Cu-Based Metal-Organic Framework.

This paper describes a novel synthetic approach for the conversion of zero-valent copper metal into a conductive two-dimensional layered metal-organic framework (MOF) based on 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) to form Cu3(HHTP)2. This process enables patterning of Cu3(HHTP)2 onto a variety of flexible and porous woven (cotton, silk, nylon, nylon/cotton blend, and polyester) and non-woven (weighing paper and filter paper) substrates with microscale spatial resolution. The method produces conductive textiles with sheet resistances of 0.1-10.1 MΩ/cm2, depending on the substrate, and uniform conformal coatings of MOFs on textile swatches with strong interfacial contact capable of withstanding chemical and physical stresses, such as detergent washes and abrasion. These conductive textiles enable simultaneous detection and detoxification of nitric oxide and hydrogen sulfide, achieving part per million limits of detection in dry and humid conditions. The Cu3(HHTP)2 MOF also demonstrated filtration capabilities of H2S, with uptake capacity up to 4.6 mol/kgMOF. X-ray photoelectron spectroscopy and diffuse reflectance infrared spectroscopy show that the detection of NO and H2S with Cu3(HHTP)2 is accompanied by the transformation of these species to less toxic forms, such as nitrite and/or nitrate and copper sulfide and Sx species, respectively. These results pave the way for using conductive MOFs to construct extremely robust electronic textiles with multifunctional performance characteristics.

China's Trade of Agricultural Products Drives Substantial Greenhouse Gas Emissions.

China's trade of agricultural products has expanded rapidly over the past two decades, resulting in considerable shifts in greenhouse gas (GHG) emissions worldwide. This study aims to explore the evolution of GHG emissions embodied in China's trade of agricultural products from 1995 to 2015. The GHG emissions embodied in China's exports of agricultural products experienced three stages of fluctuation, showing a significant upward trend (1995-2003), a fluctuating trend (2004-2007), and a fall back to the previous level (2008-2015). The embodied GHG emissions in China's imports were witnessed at times of sustained growth, rising from 10.5 Mt CO2-eq in 1995 to 107.7 Mt CO2-eq in 2015. The net import of embodied GHG emissions has grown at an average annual rate of 25.1% since 2008. In terms of regional contribution, the distribution of China's trading partners tended to be diversified. The increasing net imports of oil crops to China resulted in a significant GHG emissions shift from China to the US and Brazil. Asian countries contributed to 76.9% of the total GHG emissions embodied in China's agricultural exports. The prominent impacts of China's trade of agricultural products on global GHG emissions provide important implications for climate-related policy choices.

Surface-Clean Au25 Nanoclusters in Modulated Microenvironment Enabled by Metal-Organic Frameworks for Enhanced Catalysis.

Metal nanoclusters (NCs) with atomically precise structures have sparked interest in catalysis. Unfortunately, their high aggregation tendency and the spatial resistance of surface ligands pose significant challenges. Herein, Au25 NCs are encapsulated into isoreticular metal-organic frameworks (MOFs), namely UiO-66-X (X = H, NH2, OH, and NO2), followed by the removal of surface ligands on Au25 NCs. The resulting surface-clean Au25 NCs, protected by the MOF spatial confinement, exhibit much superior activity and stability with respect to pristine Au25 NCs in the oxidative esterification of furfural. Remarkably, experimental and theoretical results jointly demonstrate that diverse functional groups on UiO-66-X modulate the Au25 electronic state, giving rise to the discriminated substrate adsorption energy of Au25@UiO-66-X. As a result, the high electron density and suitable substrate adsorption ability dominate the activity trend: Au25@UiO-66-NH2 > Au25@UiO-66-OH > Au25@UiO-66 > Au25@UiO-66-NO2. This work develops a new strategy for the stabilization of surface-clean metal NCs in pore wall-engineered MOFs for enhanced catalysis.

Poly(methacrylate citric acid) as a Dual Functional Carrier for Tumor Therapy.

Owing to its pH-sensitive property and chelating Cu2+ effect, poly(methacrylate citric acid) (PCA) can be utilized as a dual functional nanocarrier to construct a nanodelivery system. Negatively charged carboxyl groups can interact with positively charged antineoplastic drugs through electrostatic interaction to form stable drug nanoparticles (NPs). Through drug experimental screening, doxorubicin (DOX) was selected as the model drug, PCA/DOX NPs with a diameter of 84 nm were prepared, and the drug-loading content was 68.3%. PCA/DOX NPs maintained good stability and a sustained release profile. Cell experiments presented that PCA/DOX NPs could inhibit effectively the growth of 4T1 cells; the IC50 value was decreased by approximately 15-fold after incubation for 72 h. The cytotoxicity toward H9C2 was decreased significantly. Moreover, based on its ability to efficiently adsorb copper ions, PCA showed good vascular growth inhibition effect in vitro. Furthermore, animal experiments showed that PCA/DOX NPs presented stronger anticancer effects than DOX; the tumor inhibition rate was increased by 1.5-fold. Myocardial toxicity experiments also confirmed that PCA reduced the cardiotoxicity of DOX. In summary, PCA/DOX NPs show good antitumor efficacy and low toxicity, and have good potential for clinical application.

Optimization of Naringenin Nanoparticles to Improve the Antitussive Effects on Post-Infectious Cough.

Naringenin (NRG) is a natural compound with several biological activities; however, its bioavailability is limited owing to poor aqueous solubility. In this study, NRG nanoparticles (NPs) were prepared using the wet media milling method. To obtain NRG NPs with a small particle size and high drug-loading content, the preparation conditions, including stirring time, temperature, stirring speed, and milling media amount, were optimized. The NRG (30 mg) and D-α-tocopherol polyethylene glycol succinate (10 mg) were wet-milled in deionized water (2 mL) with 10 g of zirconia beads via stirring at 50 °C for 2 h at a stirring speed of 300 rpm. As a result, the NRG NPs, with sheet-like morphology and a diameter of approximately 182.2 nm, were successfully prepared. The NRG NPs were stable in the gastrointestinal system and were released effectively after entering the blood circulation. In vivo experiments indicated that the NRG NPs have good antitussive effects. The cough inhibition rate after the administration of the NRG NPs was 66.7%, cough frequency was three times lower, and the potential period was 1.8 times longer than that in the blank model group. In addition, the enzyme biomarkers and histological analysis results revealed that the NRG NPs can effectively regulate the inflammatory and oxidative stress response. In conclusion, the NRG NPs exhibited good oral bioavailability and promoted antitussive and anti-inflammatory effects.

Hydrophilic Poly(glutamic acid)-Based Nanodrug Delivery System: Structural Influence and Antitumor Efficacy.

Poly(amino acids) have advanced characteristics, including unique secondary structure, enzyme degradability, good biocompatibility, and stimuli responsibility, and are suitable as drug delivery nanocarriers for tumor therapy. The isoform structure of poly(amino acids) plays an important role in their antitumor efficacy and should be researched in detail. In this study, two kinds of pH-sensitive isoforms, including α-poly(glutamic acid) (α-PGA) and γ-PGA, were selected and used as nanocarriers to prepare a nanodrug delivery system. According to the preparation results, α-PGA can be used as an ideal drug carrier. Selecting doxorubicin (DOX) as the model drug, an α-PGA/DOX nanoparticle (α-PGA/DOX NPs) with a particle size of 110.4 nm was prepared, and the drug-loading content was 66.2%. α-PGA/DOX NPs presented obvious sustained and pH-dependent release characteristics. The IC50 value of α-PGA/DOX NPs was 1.06 ± 0.77 µg mL-1, decreasing by approximately 8.5 fold in vitro against 4T1 cells after incubation for 48 h. Moreover, α-PGA/DOX NPs enhanced antitumor efficacy in vivo, the tumor inhibition rate was 67.4%, increasing 1.5 fold over DOX injection. α-PGA/DOX NPs also reduced the systemic toxicity and cardiotoxicity of DOX. In sum, α-PGA is a biosafe nanodrug delivery carrier with potential clinical application prospects.

Preparation of Naringenin Nanosuspension and Its Antitussive and Expectorant Effects.

Naringenin (NRG) is a natural flavonoid compound abundantly present in citrus fruits and has the potential to treat respiratory disorders. However, the clinical therapeutic effect of NRG is limited by its low bioavailability due to poor solubility. To enhance the solubility, naringenin nanosuspensions (NRG-NSps) were prepared by applying tocopherol polyethylene glycol succinate (TPGS) as the nanocarrier via the media-milling method. The particle size, morphology, and drug-loading content of NRG-NSps were examined, and the stability was evaluated by detecting particle size changes in different physiological media. NRG-NSps exhibited a flaky appearance with a mean diameter of 216.9 nm, and the drug-loading content was 66.7%. NRG-NSps exhibited good storage stability and media stability. NRG-NSps presented a sustainable release profile, and the cumulative drug-release rate approached approximately 95% within 7 d. NRG-NSps improved the antitussive effect significantly compared with the original NRG, the cough frequency was decreased from 22 to 15 times, and the cough incubation period was prolonged from 85.3 to 121.6 s. Besides, NRG-NSps also enhanced expectorant effects significantly, and phenol red secretion was increased from 1.02 to 1.45 µg/mL. These results indicate that NRG-NSps could enhance the bioavailability of NRG significantly and possess a potential clinical application.