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A simple and general red light-induced oxidation of organoboron compounds to obtain hydroxyl has been developed with spinach as the photocatalyst in alcohol.

A Pd-catalyzed regio- and stereoselective alkynylallylation of a specific C-C σ bond in cyclopropenes, using allyl propiolates as both allylation and alkynylation reagents, has been achieved for the first time. By merging selective C(sp2 )-C(sp3 ) bond scission with conjunctive cross-couplings, this decarboxylative reorganization reaction features fascinating atom and step economy and provides an efficient approach to highly functionalized dienynes from readily available substrates. Without further optimization, gram-scale products can be easily obtained by such a simple, neutral, and low-cost catalytic system with high TONs. DFT calculations afford a rationale toward the formation of the products and indicate that the selective insertion of the double bond of cyclopropenes into the C-Pd bond of ambidentate Pd complex and the subsequent nonclassical β-C elimination promoted by 1,4-palladium migration are critical for the success of the reaction.

Mulberry leaf is a common vegetable with a variety of beneficial effects, such as hypoglycemic activity. However, the underlying mechanism of its hypoglycemic effect have not been fully revealed. In this study, two flavonoid derivatives were isolated from mulberry leaves, a new geranylated flavonoid compound (1) and its structural analogue (2). The structures of compounds 1 and 2 were elucidated using spectroscopic analysis. To study the potential hypoglycemic properties of these compounds, their regulatory effects on protein tyrosine phosphatase 1B (PTP1B) were investigated. In comparison to oleanolic acid, compounds 1 and 2 showed significant inhibitory activities (IC50 = 4.53 ± 0.31 and 10.53 ± 1.76 μM) against PTP1B, the positive control (IC50 = 7.94 ± 0.76 μM). Molecular docking predicted the binding sites of compound 1 to PTP1B. In insulin-resistance HepG2 cell, compound 1 promoted glucose consumption in a dose-dependent manner. Furthermore, western blot and polymerase chain reaction analyses indicated that compound 1 might regulate glucose consumption through the PTP1B/IRS/PI3K/AKT pathway. In conclusion, geranylated flavonoids in mulberry leaves inhibite PTP1B and increase the glucose consumption in insulin-resistant cells. These findings provide an important basis for the use of mulberry leaf flavonoids as a dietary supplement to regulate glucose metabolism.

The influence of strontium doping on the adsorption of methanol on calcium oxide surface was investigated by molecular simulation. The model for methanol adsorption onto the CaO(100) and CaO(100)-Sr surfaces was constructed; the adsorption energy and activation energy were then calculated and the density of states was portrayed for the methanol bond on the calcium oxide surface. The methanol activation degrees on the calcium oxide surface before and after strontium doping were then compared by analyzing the Mulliken atomic charge population and deformation density. The results illustrate that the adsorption of methanol onto the calcium oxide surface can be significantly enhanced through the strontium doping; moreover, the enhancement increases with an increase in the doping content of strontium. After doping calcium oxide with strontium, the energy required for methanol activation is reduced; as a result, the strontium doping can also enhance the activation degree of methanol, as methanol is activated upon adsorption onto the calcium oxide surface.

Two new prenylated coumarins, 3'-hydroxytoddanone (

The paper aims to analyze the shielding properties of concrete and lead materials against gamma rays at different energies, and the relationships between the shield thickness of the two materials and gamma ray energy and attenuation factor have been obtained by using the method of attenuation multiple and the method of half-value-thickness, respectively. The results show that when the gamma ray energy and the attenuation factor are determined, the thickness of the concrete shield layer obtained by the method of attenuation multiple is greater than that obtained by the half-value-thickness method. The relative magnitude of thickness of lead shield obtained by the method of attenuation multiple and the method of half-value-thickness method is relate to the gamma ray energy. When the gamma ray energy is lower than 8 MeV, the thickness of lead shield calculated by the method of attenuation multiple is larger than that obtained by the half-value-thickness method, while when the gamma ray energy is higher than 8 MeV, the conclusion is opposite.

Halloysite nanotubes (HNTs) as a natural and inexpensive clay mineral with hollow nanotubular structures, good biocompatibility and active surfaces have been ubiquitously applied in many fields. In this work, a novel multifunctional core-shell sorbent based on HNTs, CuCl2-HNTs encapsulated magnetic microspheres (SiO2@Fe3O4), was successfully fabricated and applied for Hg0 removal from flue gas with good performance for the first time. The core-shell structure prevented the composites from aggregating but kept their magnetism, which enabled the adsorbents being easily separated for reuse by an external magnetic field. In addition, the special structure also significantly enhanced the adsorption capacity of the composites by dispersing the CuCl2 modified HNTs on the prepared magnetic microspheres. The adsorption performance was comprehensively investigated and fitted by dynamic models. The adsorption followed surface adsorption, particle diffusion and chemisorption with very good SO2 tolerance. The Cu+, Cl- and lattice oxygen were the crucial components for Hg0 removal. In order to further understand the possible mechanism, an online home-made coupling system of temperature-programmed decomposition (TPD) was used to investigate the mercury species on the spent adsorbent in addition to X-ray photoelectron spectroscopy analysis. The results confirmed the mercury species adsorbed were primarily Hg0, HgO and HgCl2.

A new xanthyletin-type coumarin, neopeucedalactone (1), was isolated from the roots of Peucedanum praeruptorum Dunn. Its chemical structure was elucidated based on extensive spectroscopic interpretation. The absolute configurations of xanthyletin-type coumarin were determined by comparing experimental and calculated ECD spectra for the first time. Compound 1 exhibited moderate cell growth inhibitory activities in vitro against human leukemic HL-60, THP-1 cell lines, and human prostate cancer PC-3 cell lines, with IC50 values of 9.97, 27.80, and 48.68 µM, respectively.

To obtain the optimization design of neutron shielding by iron/borated-polyethylene composite structure, we built a neutron shielding model of two layers of iron and borated-polyethylene. For neutron with various energies, the neutron transmission coefficients of iron/borated-polyethylene composite shield with different thicknesses were obtained by using Monte Carlo method. The simulation results show that, when neutron energy is 14 MeV and the total thickness of the composite shield is 40 cm, 60 cm and 80 cm, the optimal thickness ratio of iron to borated-polyethylene is about 0.7: 0.3, 0.725: 0.275, and 0.75: 0.25, respectively. The optimal thickness ratio of iron to borated-polyethylene is usually higher than the case of iron/polyethylene composite structure.

With bioassay- and chemistry-guided fractionation, seven new caged prenylxanthones including two scalemic mixtures, epiisobractatin (1), 13-hydroxyisobractatin (2), 13-hydroxyepiisobractatin (3), 8-methoxy-8,8a-dihydrobractatin (4), 8-ethoxy-8,8a-dihydrobractatin (5), garcibracteatone (6), and 8-methoxy-8,8a-dihydroneobractiatin (7), and the eight known compounds 8-15 were isolated from the leaves of Garcinia bracteata. The structures were unambiguously elucidated through analysis of spectroscopic data. The 2D structures and relative configurations of 1 and 5 were confirmed by X-ray crystallographic analysis. The separation of the enantiomers of 1-5 was accomplished by chiral-phase HPLC. The absolute configurations of the enantiomers of 1 and 5 were assigned by comparison of the experimental and calculated electronic circular dichroism (ECD) spectra. The absolute configurations of the related compounds were determined via comparisons of their ECD data with those of the enantiomers of 1 and 5, respectively. Notably, compound 7, with a neo caged skeleton, is the first representative of a novel type of caged xanthone lacking a Δ

In our efforts to find potential agents for the treatment of Alzheimer's disease in naturally occurring compounds, a systematic investigation for the active constituents of Flemingia philippinensis was carried out. Four new prenylated isoflavones, philippinone A-D (1-4), together with six known analogues (5-10), were obtained from the roots of Flemingia philippinensis. Their structures were established through extensive physical and spectroscopic data analysis. All the isolates were evaluated for their inhibitory effect of self-induced Aβ aggregation among which compound 5 showed significant Aβ aggregation inhibitory ability with the inhibitory rate of 70.56%. The results of molecular docking experiment for compounds 1 and 6 corresponded to that of the thioflavin-T assay. Moreover, the results further clarified the effects of different substituent group of tested compounds on the Aβ aggregation inhibition. A preliminary structure-activity relationship is further discussed. Our results suggested that the isoflavonoids may mitigate the progression of AD and compounds 2 and 5 may be a candidate in the treatment of AD.

Neobraclactones A–C (1–3), featuring an unprecedented further rearranged prenylxanthone skeleton with a unique octahydro-2H-1,3-dioxacyclopenta[c,d]inden-2-one scaffold, along with their biosynthesis-related known compound neobractatin (4), were isolated from the leaves of Garcinia bracteata. Their structures with absolute configurations were determined by extensive analyses of spectroscopic data and ECD calculations. Compounds 1 and 2 showed significant growth inhibition activities against the human leukaemia HL-60 and K562 cell lines with GI50 values from 0.40 to 0.86 μM.

A copper-catalysed three-component iodoalkynylation reaction of arynes for the expeditious and versatile synthesis of o-alkynyl aryl iodides has been developed. Mechanism research shows that the reaction goes through two steps enabled by copper catalysis: the formation of 1-iodo-2-arylacetylene and the insertion of the aryne into a C(sp)–I bond.

A new xanthyletin-type coumarin, neopeucedalactone (

Plants infected by fungal elicitors produce phytoalexins. As one of the most valuable traditional medicines, dragon’s blood is harvested from the trunks of Dracaena cochinchinensis elicited by fungal species. However, the functional metabolites exhibiting antifungal activity in dragon's blood remain unclear. In the current study, three new stilbenoids (1―3), one new chalcone (4), and one new flavane (5), together with one known compound (6), were identified from dragon’s blood of D. cochinchinensis elicited by Fusarium graminearum. Among these compounds, compound 3, (7E)-2,4-dihydroxy-1-methylstilbene, exhibited a broad-spectrum inhibitory activity against four pathogenic fungal strains of maize, including Exserohilum turcicum, Bipolaris maydis, Curvularia lunata, and F. graminearum. Inspiringly, compound 3 showed a stronger inhibitory activity (half-maximal inhibitory concentration, IC50: 11.02 ± 1.12 μg/mL) against the elicited fungus F. graminearum than that of a commercial fungicide, nystatin (IC50: 16.23 ± 3.10 μg/mL). Additionally, a dramatically low electron density was observed in the cell walls of F. graminearum, suggesting that compound 3 might exert its function by directly targeting cell walls. Compound 3 also showed potent antioxidant activities, which was validated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical inhibition assays. Collectively, our findings highlight that stilbenoids in dragon’s blood of D. cochinchinensis have promising potential for the future development of natural fungicides for organic farming.

NaOH, Na2CO3 and NaNO3 loaded on carbide slag are used as transesterification catalysts in a batch-type transesterification system. The activated catalysts are characterized by X-ray diffraction and the corresponding catalytic efficiencies are compared. NaOH loaded on calcined carbide slag gains the highest catalytic efficiencies. The optimal activated temperature of NaOH loaded on calcined carbide slag is obtained.

Materials developed from Broussonetia papyrifera have been widely used in food and paper industries, but this root bark of the plant has been overlooked despiteits potentially economic values. Thus, the aim of the present study was to develop the root bark of B. papyrifera as a source of bioactive compounds. Chemical investigation of the bark of B. papyrifera led to the isolation of nine flavonoids derivatives (1-9) and two coumarins (10-11), which includes five new compounds (1–4 and 11). The structures of isolates were elucidated based on spectroscopic analyses. All the isolates were evaluated for their biological effects including tyrosinase inhibition, cytotoxicity, and anti-inflammatory activity. Compound 3 showed inhibition activity against tyrosinase with an IC50 value of 9.29 μM (positive control, kojic acid: 30.56 μM). Molecular docking was used to support their inhibition activities which indicated that hydrogen bond formation played an important role in the ligand-enzyme complex. In addition, compound 4 exhibited cytotoxic activity against three cancer cell lines (NCI-H1975, HepG2, and MCF-7) and the structure-activity relationship of flavonoids (1-9) were established. Results from anti-inflammatory assay showed that compound 1 inhibited the production of IL-2 in Jurkat cells induced by phytohemagglutinin (PHA) and phorbol 12-myristate 13-acetate (PMA), with immunosuppressive activity. Overall, our study suggests that flavonoids from root bark of B. papyrifera can be used as a valuable source of bioactive compounds and support its use as a crop benefits to local economic.

Methyl α-isocupreine catalyst is successfully applied in the asymmetric [4 + 1] annulation of 3-bromooxindoles (I) with 1-azadienes (II) leading to spirocyclic dihydropyrrole-oxindoles (III) in excellent enantioselectivities.

One of the most important steps in the wet limestone–gypsum flue gas desulfurization (WFGD) process is limestone dissolution, which provides the dissolved alkalinity necessary for SO2 absorption. Accurately evaluating the rate controlling step in sorbent dissolution process is important in the design and efficient operation of WFGD plants. In the present work, the kinetics of paper white mud(PWM) in dissolution process has been studied by using a pH-stat method. The results obtained indicated that PWM dissolution in WFGD conditions obeys the modified shrinking core model. PWM dissolution kinetics follows the film diffusion and surface reaction control and the rate controlling step of PWM is film diffusion control. The activation energies of PWM in film diffusion and surface reaction steps are 11.9±0.7 kJ/mol and 13.7±1.3 kJ/mol, respectively.

Calcium-based minerals cyclic calcination/carbonation reaction is an effective approach to CO2 capture for coal-fired power plants. It was proposed that dolomite modified with acetic acid solution, i.e. calcium magnesium acetate (CMA), acted as a new CO2 sorbent for calcination/carbonation cycles. The carbonation conversions for CMA and dolomite with the number of cycles were experimentally investigated. The cyclic conversion for CMA is much greater than that for dolomite for the carbonation at 650-700 °C. The carbonation conversion for CMA achieves as high as 0.6 after 20 cycles. CMA maintains the great conversion for calcination at 1100 °C. CMA had a better anti-sintering than dolomite. The pore volume and pore area distributions for calcined CMA are superior to those for calcined dolomite.

Five xanthones, 1,4,5,6-tetrahydroxyxanthone (1) and bracteaxanthones III-VI (2-5) together with twenty-six known compounds (6-31), were isolated from the ethanol extract of the stem bark of Garcinia bracteata. Their structures were elucidated via spectroscopic analyses. Growth inhibitory activities of these compounds against the human leukaemic HL-60 cell line were measured in vitro. Compounds 7, 11, and 29 exhibited moderate activities with GI(50) values of 2.8, 3.4, and 3.1 μM, respectively, and a preliminary structure-activity relationship is discussed.

Thermal decomposition characteristics of two kinds of calcium based organic compounds-calcium propionate and the product of the modified calcium hydroxide by propionic acid-under O2/N2 atmosphere and O2/CO2 atmosphere are investigated through thermogravimetric analysis. Thermal events of CP and MCP are divided into three segments. The second and the third ones for the two compounds are similar. O2/CO2 atmosphere reduces mass loss rate peak of the second segment and postpone the third segment. O2 concentration of 10 % is inadequate for a fast and sufficient reaction. When O2 concentration is enriched to 20 %, the whole process is shifted towards lower temperature zone. Further heightening O2 concentration to 30 % or 40 %, the effect is not remarkable.

Subscript textThe kinetic model for simulating the mechanism of the promoted effect of methanol on the NOxOUT process has been established and it mainly includes the optimal sub-mechanisms respectively for the NOxOUT process and the chemical reaction of methanol. The oxygen concentration does not obviously influence the maximum NO reduction efficiency in the range of 1-6 %, but the temperature window is overall shifted to lower temperature zone with oxygen concentration increased. Meanwhile, the mole ratio of urea to nitric oxide by a factor of 2 should be maintained between 1.5 and 2 from both the efficiency and running cost view. Also, ample residence time of 300/T-400/T s must be guaranteed for the reduction occurring thoroughly. Methanol does not compromise the maximum NO reduction efficiency and broadens the temperature window towards low temperature zone. The promoted mechanism of methanol on the NOxOUT process is the abundant OH formation through the methanol regenerative reaction of CH2OH/CH3O+H2O=CH3OH+OH and methanol should be maintained at 50-100 ppm for an obvious promoted effect. During the co-injection of methanol and urea, the “ammonia slip” is depressed, especially at 1173 K where the promoted effect on NO reduction is obvious, but emission of nitrous oxide is also markedly increased at this temperature.

Nitric oxide (NO) reduction through coal, biomass and their blend reburning is conducted on a drop tube furnace experimental system and it is proved to be feasible of using the coal-biomass blend as the reburning fuel. For a high NO reduction efficiency, the excess air ratio in the reburning zone should be less than 0.9 and the reaction temperature is required to be higher than 1373K. 50-60% of the biomass percentage in the blend is enough for an acceptable efficiency. At the same time, for a thorough NO reduction process, the reburning fuel fraction and the residence time in the reburning zone must be guaranteed about 20% and 0.6-0.8s, respectively. Also, when the initial NO concentration is excess 600ppm, the efficiency is varied little at different NO concentrations.

The enhancement of alkaline industrial wastes on the desulfurization performance and utilization of limestone has already been found. In order to explore the reason of this phenomenon from the kinetic point of view, two typical alkaline wastes, carbide slag with a high calcium content and Bayer process red mud with more metal impurities, were adopted to research. Kinetic behavior of calcination reaction was calculated using the isoconversional method of Kissinger-Akahira-Sunose method (a differential method) and Flynn-Wall-Ozawa method (an integral method) at four different heating rates: 10, 20, 40 and 80 K•min-1. Values calculated by these two methods are very close, and the calculated result shows that calcination rate constant of modified limestone is obviously greater than that of original limestone, under the same calcination temperature, which means that alkaline wastes are advantageous to the thermal decomposition of limestone.

Ammonium ylides have a long history in organic synthesis, but their application in asymmetric catalysis is still underdeveloped in regard to both substrate scope and reaction pathways compared with phosphorus and sulfur ylides. Here a previously unreported asymmetric [4 + 1] annulation reaction of 3-bromooxindoles and electron-deficient 1-azadienes has been developed through ammonium ylide catalysis of a newly designed 2'-methyl α-isocupreine (α-MeIC), efficiently delivering spirocyclic oxindole compounds incorporating a dihydropyrrole motif in excellent enantioselectivity (up to 99% ee). To the best of our knowledge, this work represents the first example of asymmetric catalysis of ammonium ylides bearing α-substitutions, and the catalytic [4 + 1] annulation pathway of ammonium ylides is also unprecedented. Moreover, (1)H NMR, mass spectroscopy, and computational calculation studies were conducted, and the catalytic cycle and a tentative explanation of the enantioselective mechanism have been successfully elucidated.

A rapid thermal process (RTP) was first introduced into the intrinsic gettering (IG) processes of fast neutron irradiated Czochralski (CZ) silicon. The effect of RTP conditions on bulk microdefects (BMDs) and denuded zone (DZ) was investigated. Fourier transform infrared absorption spectrometer (FTIR) was used to measure the concentration of interstitial oxygen ([Oi]). Bulk microdefects were observed by optical microscope. The results show that, according to the variation of [Oi], it is found that RTP doesn't change the processes of oxygen precipitation in fast neutron irradiated Czochralski silicon. Perfect denuded zone, dense oxygen precipitates and defects form in the bulk of irradiated samples. With increasing temperature of RTP, the width of denuded zone decreases. Increasing RTP cooling rate, the density of Bulk microdefects increases. DZ forms in the sample that annealed in nitrogen atmosphere.

The difference of annealing behaviors of vacancy-oxygen complex (VO) in varied dose neutron irradiated Czochralski silicon: (S1 5×10 17 n/cm 3 and S2 1.07×10 19 n/cm 3 ) were studied. The results show that the VO is one of the main defects formed in neutron irradiated Czochralski silicon (CZ-Si). In this defect, oxygen atom shares a vacancy, it is bonded to two silicon neighbors. Annealed at 200 °C, divacancies are trapped by interstitial oxygen(O i ) to form V 2 O (840 cm −1 ). With the decrease of the 829 cm −1 (VO) three infrared absorption bands at 825 cm −1 (V 2 O 2 ), 834 cm −1 (V 2 O 3 ) and 840 cm −1 (V 2 O) will rise after annealed at temperature range of 200–500 °C. After annealed at 450–500 °C the main absorption bands in S1 sample are 834 cm −1 , 825 cm −1 and 889 cm −1 (VO 2 ), in S2 is 825 cm −1 . Annealing of A-center in varied neutron irradiated CZ-Si is suggested to consist of two processes. The first is due to trapping of VO by O i in low dose neutron irradiated CZ-Si (S1) and the second is due to capture the wandering vacancy by VO, etc, in high dose neutron irradiated CZ-Si (S2), the VO 2 plays an important role in the annealing of A-center. With the increase of the irradiation dose, the annealing behavior of A-center is changed.

A new compound, 3β,18,19β-trihydroxylupane, was isolated from Garcinia tetralata, along with five known compounds, garcinexanthone B, morolic acid acetate, toxyloxanthone A, 6,11-dihydroxy-2,2-dimethylpyrano[3,2-c]xanthen-7(2H)-one, and 1,4-dihydroxy-5,6-dimethoxy-xanthone. The structure of the new compound was established by extensive spectroscopic techniques.

Investigations of the constituents of the stem barks of Garcinia xanthochymus have yielded two new compounds, garcinenones X (1) and Y (2), along with five known xanthones, 1,4,5,6-tetrahydroxy-7-(3-methylbut-2-enyl)xanthone (3), 1,4,6-trihydroxy-5-methoxy-7-(3-methylbut-2-enyl)xanthone (4), 1,4,5,6-tetrahydroxy-7,8-di(3-methylbut-2-enyl)xanthone (5), 1,3,5,6-tetrahydroxy-4,7,8-tri(3-methylbut-2-enyl)xanthone (6), and 1,5,6-trihydroxy-7,8-di(3-methylbut-2-enyl)-6′,6'dimethylpyrano(2′,3′:3,4)xanthone (7). The structures of the compounds were determined by spectroscopic methods. The cell growth inhibitory activity of the isolated compounds against the PC-3 cell line was measured. Among them, compounds 2, 3, 5, and 6 exhibited significant inhibitory effects with IG50 values of 14.3, 15.5, 11.1, and 6.8 μM, respectively.