Research on and Model Analysis of Flexural Mechanical Properties of Basic Magnesium Sulfate Cement Concrete Beams.

This study presents a comprehensive investigation into the mechanical properties of Basic Magnesium Sulfate Cement Concrete (BMSC) in comparison to Ordinary Portland Cement Concrete (OPC) within reinforced concrete components. The main objective is to evaluate BMSC's applicability for practical engineering purposes, with a focus on its with early high strength, improved toughness, and superior crack resistance compared to conventional concrete. Experimental procedures involved fabricating beam specimens using OPC concrete with a C40 strength grade, alongside BMSC beams with varying strength grades (C30, C40, and C50). These specimens underwent bending resistance tests to analyze crack patterns and mechanical characteristics. The findings reveal that BMSC beams demonstrate enhanced bending and tensile properties at equivalent strength grades compared to OPC beams. Particularly, cracking mainly occurred at the mid-span region of BMSC beams, characterized by narrower cracks, indicating superior crack resistance. However, it was noted that the toughness of BMSC beams decreases as the strength grade increases. The maximum mid-span deflection of the BMSC test beam was smaller than that of the OPC test beam, which was 3.8 mm and 2.6 mm, respectively. The maximum crack width of the OPC beam was 4.7 times that of the BMSC beam. To facilitate practical implementation, the study developed calculation models for estimating the crack bending distance and ultimate bending distance in BMSC beams, offering valuable tools for engineering design and optimization. Overall, this research provides significant insights into the mechanical behavior of BMSC, presenting potential advantages for structural engineering applications.

Fibulin-1 promotes intimal hyperplasia after venous stent implantation through ACE mediated angiotensin II signaling.

Objective: Stent intimal hyperplasia leads to in stent restenosis and thrombosis. This study determined whether Fibulin-1 activity in smooth muscle cells (SMCs) contributes to stent restenosis or thrombosis. Methods: Stent implantation was conducted in a pig model. Target vessel samples were stained and analyzed by protein mass spectrometry. Cell experiments and Fibulin-1 SMC specific knockout mice (Fbln1SMKO) were used to investigate the mechanism of Fibulin-1 induced SMC proliferation and thrombosis. Results: SMC proliferation and phenotypic transition are the main pathological changes of intimal hyperplasia in venous stents. Protein mass spectrometry analysis revealed a total of 67 upregulated proteins and 39 downregulated proteins in intimal hyperplasia after stent implantation compared with normal iliac vein tissues. Among them, Fibulin-1 ranked among the top proteins altered. Fibulin-1 overexpressing human SMCs (Fibulin-1-hSMCs) showed increased migration and phenotypic switching from contractile to secretory type and Fibulin-1 inhibition decreased the activity of SMCs. Mechanistically, Fibulin-1-hSMCs displayed increased levels of angiotensin converting enzyme (ACE) expression and angiotensin II signaling. Inhibition of ACE or angiotensin II signaling alleviated the migration of Fibulin-1-hSMCs. Using Fibulin-1 SMC specific knockout mice (Fbln1SMKO) and venous thrombosis model, we demonstrated that Fibulin-1 deletion attenuated intimal SMCs proliferation and thrombosis. Further, Fibulin-1 concentration was high in iliac vein compression syndrome (IVCS) patients treated with stent and was an independent predictor of venous insufficiency. Conclusions: Fibulin-1 promotes SMC proliferation partially through ACE secretion and angiotensin II signaling after stent implantation. Fibulin-1 plays a role in venous insufficiency syndrome, implicating the protein in the detection and treatment of IVCS.

An interprovincial input-output database distinguishing firm ownership in China from 1997 to 2017.

Input-Output (IO) data describing supply-demand relationships between buyers and sellers for goods and services within an economy have been used not only in economics but also in scientific, environmental, and interdisciplinary research. However, most conventional IO data are highly aggregated, resulting in challenges for researchers and practitioners who face complex issues in large countries such as China, where firms within the same IO sector may have significant differences in technologies across subnational regions and different ownerships. This paper is the first attempt to compile China's interprovincial IO (IPIO) tables with separate information for mainland China-, Hong Kong, Macau, Taiwan-, and foreign-owned firms inside each province/industry pair. To do this, we collect relevant Chinese economic census data, firm surveys, product level Custom trade statistics, and firm value-added tax invoices and consistently integrate them into a 42-sector, 31-province IO account covering 5 benchmark years between 1997-2017. This work provides a solid foundation for a diverse range of innovative IO-based research in which firm heterogeneity information about location and ownership matters.

Euphorfinoids A and B, a pair of ent-atisane diterpenoid epimers from the roots of Euphorbia fischeriana, and their bioactivities.

Euphorfinoids A and B (1 and 2), a pair of ent-atisane diterpenoid epimers with a vicinal 2,3-diol moiety, together with four known analogues (3-6), were isolated from the roots of wild Euphorbia fischeriana. Their structures were elucidated by spectroscopic analysis, including extensive NMR, HR-ESIMS, NMR calculations, X-ray diffraction, and comparison with structurally related known analogues. Our bioassays have established that compound 1 displayed moderate anti-proliferative effects on Hcc1806 cell line with IC50 15.53 ± 0.21 µM, and compound 5 showed remarkable inhibitory effects against AChE with IC50 32.56 ± 2.74 µM by an in vitro screened experiment.

Multi-threshold splitting tree algorithm to reduce the number of filters in programmable hyperspectral imaging for fast multi-target classification.

Programmable hyperspectral imaging is a promising and efficient technique for fast target classification by coding hyperspectral post-processing algorithms as spectral transmittances, which enables such post-processing to be directly performed by special optical dispersive element during the process of optical imaging. Compared with conventional hyperspectral imaging and post-processing techniques, it shows significant advantages of fast image acquisition, post-processing free, and a much lower load of data transmission and storage. However, when multi-target classification tasks are encountered, the speed would decrease seriously due to the requirement of a large number of filters. In this study, a novel splitting strategy is proposed to reduce the number of filters in programmable hyperspectral imaging for fast multi-target classification while maintaining the classification performance. Numerical simulation experiments were performed on six publicly available hyperspectral data sets. Compared with the conventional splitting strategies, the proposed splitting strategy can reduce the number of filters by 25% to 80% and achieve similar classification performance, which is of great significance to improve the speed of multi-target classification with programmable hyperspectral imaging technique.

Diastereoselective Synthesis of Chromeno[3,2-d]isoxazoles via Brønsted Acid Catalyzed Tandem 1,6-Addition/Double Annulations of o-Hydroxyl Propargylic Alcohols.

A Brønsted acid catalyzed tandem process to access densely functionalized chromeno[3,2-d]isoxazoles with good to excellent yields and diastereoselectivities was disclosed. The procedure is proposed to involve a 1,6-conjugate addition/electrophilic addition/double annulations process of alkynyl o-quinone methides (o-AQMs) in situ generated from o-hydroxyl propargylic alcohols with nitrones. Mild conditions, good functional group compatibility, easy scale-up of the reaction, and further product transformation demonstrated its potential application.

One-pot catalyst-free synthesis of benzopyrroxazine derivatives by a mutually activated sequential annulation process.

A one-pot catalyst-free reaction of o-hydroxyaryl azomethine ylides, vinyl pyridines and paraformaldehyde for the synthesis of benzopyrroxazines is reported, which offers a straightforward and atom-economical procedure for the preparation of benzopyrroxazine derivatives in moderate to excellent yields under mild conditions. A self-catalyzed [3 + 2] annulation through a mutual activation method and a sequential non-catalyzed [5 + 1] annulation process contribute to this strategy. The corresponding control experiments have been conducted to reveal the mechanism of this reaction.

Two novel polyketones from the leaves and twigs of Clerodendrum trichotomum.

Two novel polyketones, along with four known compounds, were isolated from the leaves and twigs of Clerodendrum trichotomum. Their structures were determined to be clerodendruketone A (1), clerodendruketone B (2), ecdysanols E (3), ecdysanols D (4), 5,5'-dimethoxy-7-oxolariciresinol (5), and (-)-(7'S,8S,8'R)-4,4'-dihydroxy-3,3',5,5'-tetramethoxy-7',9-epoxy-lignan-9'-ol-7-one (6) through the methods of NMR, HRESIMS and ECD data analyses. The antioxidant effects against free radical were tested by DPPH assay. The antibacterial activity against Escherichia coli and Staphylococcus aureus were tested by turbidimetry assay. The results demonstrated that compounds 1 and 2 had significative antibacterial activity, and compound 3 had moderate antioxidant activity.

Corrosion behavior of HRB400 and HRB400M steel bars in concrete under DC interference.

The influence of direct current interference on the corrosion behavior of HRB400 and HRB400M steel bars in simulated concrete solution was studied using methods such as weight loss experiment, electrochemical experiment, surface technology and product analysis. The research results showed that with the increase of DC interference voltage, the corrosion rates of HRB400 and HRB400M steel bars would increase. The corrosion resistance of HRB400M steel bars was better than HRB400 steel bars under the experimental conditions. In addition, direct current interference could cause damage to the corrosion product layer on the surface of HRB400 steel bars and HRB400M steel bars. And the corrosion form and corrosion product types of HRB400 and HRB400M steel bars would be affected by direct current interference. The main corrosion products of HRB400 steel bars included γ-FeOOH and Fe2O3 when it was not interfered by DC. When DC interference was applied, the main corrosion products included Fe3O4 and Fe2O3. The corrosion products on the surface of HRB400M steel bars were mainly Fe3O4 and Fe2O3, and the types of products increased to form Cr2O3 and MnFe2O4.

Euphorfistrines A-G, cytotoxic and AChE inhibiting triterpenoids from the roots of Euphorbia fischeriana.

Seven new triterpenoids including two cycloartanes (1-2), a lanostane (3), a tirucallane (4), a dammarane (5), an ursane (6), and an oleanane (7), along with nineteen known triterpenoids (8-26), have been obtained from the roots of Euphorbia fischeriana. Their structures were established by NMR, HRESIMS, single-crystal X-ray diffraction analysis, Mosher's method, NMR calculations, ECD analysis, and comparison with structurally related known analogues. Among them, compounds 1 and 8 were a pair of cycloartane-type triterpenoids epimers. Our bioassays have established that compounds 1-5 and 10 displayed moderate cytotoxic effects, and the structure-activity relationships of cycloartane-type triterpenoids (CTTs) were further examined. Notably, some triterpenoids displayed moderate inhibitory effects against AChE by an in vitro screened experiment. Triterpenoid 7 (Euphorfistrine G, ETG) displayed the potent inhibitory effect with IC50 = 2.45 and Ki = 2.30 µM (inhibition kinetic). And, in silico docking analyses have been performed to investigate the inhibitory mechanism of compound 7.

Euphorfinoids E-L: Diterpenoids from the roots of Euphorbia fischeriana with acetylcholinesterase inhibitory activity.

Eight undescribed diterpenoids, euphorfinoids E-L, together with twelve known analogues, were isolated from the roots of wild Euphorbia fischeriana. Their structures and absolute configurations were elucidated by a combination of NMR, MS, ECD, and X-ray diffraction analyses. The plausible biosynthetic pathway of 1 was also proposed. The isolated compounds displayed moderate inhibitory activity against acetylcholinesterase (AChE) with 50% inhibiting concentration (IC50) values of 6.23-192.38 µM.

Study on corrosion behavior of X80 steel under stripping coating by sulfate reducing bacteria.

BACKGROUND: At present, microorganism has been considered as important factors that threaten to buried pipelines with disbonded coatings. Aiming at the problem of unknown corrosion mechanism of sulfate-reducing bacteria (SRB), a series of studies have been carried out in this paper. Spectrophotometer and fluorescent labeling technology are used to study the growth and attachment of SRB in the simulated soil solution. The corrosion behavior of X80 pipeline steel with or without SRB was researched by electrochemical methods such as open circuit potential, dynamic potential polarization curve, and electrochemical impedance spectroscopy. The microscopic morphology of the corrosion products on the surface was observed with a scanning electron microscope (SEM), and the element content of the corrosion products on the surface of the sample after corrosion was observed using X-ray energy spectrum (EDS) analysis. RESULTS: The results showed that the growth and reproduction of SRB caused the pH of the soil simulated solution to increase, which may promote the corrosion of X80 steel. In addition, the cathode reaction of X80 steel in a sterile environment is the reduction of H+, and the main corrosion product is iron oxide. When the soil simulation solution contains SRB, the cathodic reaction is controlled by both H+ reduction and sulfide depolarization reactions, and FeS appears in the corrosion products. CONCLUSION: Although the life cycle of SRB is only about 14 days, the corrosion of X80 steel is greatly promoted by SRB, and even causes corrosion perforation, which will bring huge economic losses and serious safety hazards.

Is environmental regulation effective in promoting the quantity and quality of green innovation?

Green innovation (GI) is an important means of achieving a win-win outcome in the form of both economic development and environmental protection. Using a unique Chinese Patent Census Database to identify the quantity and quality of GI in each province and panel data for Chinese industrial sector in 30 provinces from 2002 to 2015, we investigated the impact of environmental regulation (ER) on GI in China. This study presents the first attempt to identify green innovation quality in China. Empirical results show that there is an inverted-U relationship between ER and GI. The heterogenous effects are further investigated in order to obtain more accurate policy implications. The results indicate that the impact of ER on GI is insignificant in the central and western regions, implying the necessity of adjusting ER policies in these regions. Second, the inverted U-shaped relationship between ER and GI only occurred in provinces with high state-owned enterprise (SOE) ratio, figuring out the special role of Chinese SOEs in promoting GI. Third, the impact of ER on GI is insignificant in regions with high levels of pollution, indicating high potential of green innovation and policy adjustments there.

Six novel lignanoids with complex structures from Sigesbeckia glabrescens Makino with their cytotoxic activities.

Six new lignanoids, Glalignin A-E (1-5) and Glaneolignin A (6), together with four analogues, (+)-isolariciresinol (7), (+)-syringaresinol (8), dihydrodehydrodiconiferyl alcohol (9) and tribulusamide A (10), were obtained from the aerial parts of Sigesbeckia glabrescens Makino and also isolated for the first time from the Sigesbeckia genus. The structures of these compounds were elucidated by the interpretation of HRESIMS, 1D NMR, 2D NMR data and chemical evidence. The cytotoxic activities of the compounds were evaluated by testing their inhibition in several tumor cells using the MTT assay. New compound 2 and 5 displayed cytotoxicity against the human cancer cell lines human lung adenocarcinoma cells (A549) with IC50 values of 32.89 ± 6.83 and 35.86 ± 6.83 µM.

Dataset of China's non-competitive constant price input-output tables for 2007 and 2012.

The China's Input-Output tables for 2007 and 2012 which were published by the China National Bureau of Statistics are competitive current price input-output tables. Based on these tables, this paper constructs the China's non-competitive constant price input-output data for 2007 and 2012. This dataset is supplementary to Ref. [1]. And we share the raw data about China's IO tables for 2007 and 2012. Furthermore, the new IO tables data which we constructed will also be uploaded.

Low Temperature Nanotailoring of Hydrated Compound by Alcohols: FeF3·3H2O as an Example. Preparation of Nanosized FeF3·0.33H2O Cathode Material for Li-Ion Batteries.

Iron fluoride is a kind of high-capacity conversion-type cathode material for lithium-ion batteries (LIBs) and shows attractive practical application potential. However, it still faces many challenges, such as poor electronic conductivity and volume change while cycling. Reducing particle size to nanoscale has been proved to be an effective way to address the poor electronic conductivity and huge volume change of iron fluoride cathodes for LIBs. In this study, a low temperature nanotailoring (LTNT) strategy is proposed to realize the conversion of microsized FeF3·3H2O to nanosized FeF3·0.33H2O by one-step treating with the assistance of alcohols. Meanwhile, the particle size and morphology of iron fluorides can be controlled by regulating the processing conditions. When evaluated as a cathode material for LIBs, the as-prepared bare FeF3·0.33H2O shows a high capacity of 190 mAh g-1 after 50 cycles with excellent rate capability. This LTNT method is applicable to hydrates and even can be extended to easily hydrated compounds.

Mn-Doped Fe1- xMn xF3·0.33H2O/C Cathodes for Li-Ion Batteries: First-Principles Calculations and Experimental Study.

Increasing attention has been paid on iron fluoride as an alternative cathode material for Li-ion batteries (LIBs) owing to its high energy density and low cost. However, the poor electric conductivity and low diffusivity for Li-ions set great challenges for iron fluoride to be used in practical LIBs. Here, we employ first-principles calculations to probe the influence of Mn-doping on the crystal structure and electronic structure of FeF3·0.33H2O. The calculated results suggest that Mn-doping can enlarge the hexagonal cavity and reduce the band gap of FeF3·0.33H2O as well as improve its intrinsic conductivity. Furthermore, Fe1- xMn xF3·0.33H2O/C ( x = 0, 0.06, 0.08, and 0.10) nanocomposites were successfully fabricated by a hydrothermal method and ball-milling. Owing to the Mn-doping effect combined with highly conductive acetylene black (AB) modification, the typical Fe0.92Mn0.08F3·0.33H2O/C composite exhibits a high discharge capacity of 180 mA h g-1 at 50 mA g-1 after 100 cycles and delivers excellent cycling stability as well as good rate capability.

Highly Efficient and Diastereoselective Construction of Trifluoromethyl-Containing Spiro[pyrrolidin-3,2'-oxindole] by a Catalyst-free Mutually Activated [3+2] Cycloaddition Reaction.

A catalyst-free self-catalyzed [3+2] cycloaddition reaction of isatin-derived α-(trifluoromethyl)imines with vinylpyridines is reported. The reaction offers a straightforward and atom-economical procedure for the preparation of a series of 5'-trifluoromethyl-spiro[pyrrolidin-3,2'-oxindoles] in excellent yields and diastereoselectivities. The reaction mechanism has been investigated by control experiments, DFT calculation of pKa values and the kinetic profiles, revealing that this reaction featured the mutual activation between isatin-derived α-(trifluoromethyl)imines and vinylpyridine to generate the reactive species.

PPh3-Catalyzed [3 + 2] Spiroannulation of 1C,3N-Bisnucleophiles Derived from Secondary ß-Ketoamides with δ-Acetoxy Allenoate: A Route to Functionalized Spiro N-Heterocyclic Derivatives.

A [3 + 2] annulation of α-substituted secondary ß-ketoamides with δ-acetoxy-modified allenoate has been developed in the presence of phosphine catalyst. In this spiroannulation reaction, ß-ketoamides were used as the bis-nucleophilic partner while the γ,δ-carbon of 5-acetoxypenta-2,3-dienoate participated as a C2 synthon, affording the desired functionalized five-membered N-heterocyclic derivatives in moderate to excellent yields and diastereoselectivities under mild conditions. Preliminary attempts on the asymmetric variant of this reaction have been also examined, giving the corresponding products with moderate ee values.