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The formation and expansion of cracks in a propellant would induce debonding at the interface between different constituents and may even cause explosion of the propellant during launch. One way to prohibit debonding is the employment of self-healing polyurethane adhesives, which can heal cracks in the early stage. In this work, polypropylene glycol and isophorone diamine were used to prepare polyurethane adhesive with high-efficiency self-healing ability. The differences between the mechanical and self-healing properties of polyurethanes with a hard segment structure composed of different isocyanates were studied. The experimental results showed that PPG-IP-PA (polyurethane synthesized using polypropylene glycol, isophorone isocyanate and isophorone diamine) has excellent mechanical properties and high-efficiency room temperature self-healing ability. When compared with other polyurethanes, PPG-IP-PA has a strong molecular chain motion ability, and its continuous ring hard segment structure ensures the overall mechanical properties. Its maximum tensile strength can be up to 3.85 MPa and elongation at break almost reached 3000%. After placing at room temperature for 12 h, the mechanical properties of PPG-IP-PA can be fully restored. When PPG-IP-PA was applied to a propellant, it can restore 70% of the tensile strength of the completely broken grain after being placed at room temperature for 12 h, and there was no obvious interference to the thermal decomposition of AP-Al components. Our results provide a new designing concept in dealing with the debonding of components in propellants.

Hydrogen bonding and mechanical refining are closely correlated. In this work, structural variations of hydrogen bonding patterns in cellulose during mechanical pulp refining, including the hydrogen bonding energy and distance as well as the content of hydrogen bonds, have been explored by using the second derivative FTIR spectra and deconvolving spectra in the OH stretching vibrational region. Results show that except for the bond distance, both the hydrogen bonding energy and the content of hydrogen bonds exhibit a significant variation at an increasing beating degree. The calculated hydrogen bonding energies for intermolecular O6H⋯O3' decrease by 12.9%, while those of intramolecular O3H⋯O5 and O2H⋯O6 vary little. Evolutions of the content of certain hydrogen bonds differ depending on the different refining stage. It is suggested that along with the role of water, hydration and swelling, internal/external fibrillation and delamination are strongly related to the structural variations of hydrogen bonding patterns in cellulose during mechanical pulp refining.

An ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method has been optimized and validated to simultaneously monitor steroidal glycoalkaloids (SGAs), α-chaconine and α-solanine, in potato samples stored under natural indoor conditions in Kunming. Two different analytical columns (Hypersil Gold C18 and ZORBAX RRHD HILIC Plus) were assessed. The ZORBAX RRHD HILIC Plus showed better separation for the SGAs. The samples in the present method were directly extracted with 10% acetic acid aqueous solution. The recoveries of SGAs in the potato flesh and skin were in the range of 86.3 to 92.3% and 86.5 to 90.5% with a precision of 2.2 to 4.5% and 3.2 to 5.3%, respectively. The intra- and inter-day validation data for accuracy were in the range of 85.00 to 105.11% with a coefficient of variation (CV) of 1.88 to 8.91% and 98.50 to 100.59% with a CV of 2.11 to 8.22%, respectively. High correlation coefficients (R2 = 0.9997 for α-chaconine and R2 = 0.9996 for α-solanine) were obtained at 2 to 400 μg L−1 SGAs. The results showed that the validation parameters of the method were in the acceptable range as recommended by the United States Food and Drug Administration (USFDA) guidelines. In addition, the SGA contents were significantly higher in the skin than those in the flesh, and significantly increased with time in the skin, but not in the flesh of potato samples.

Silicone rubber composite materials are widely used in the external insulation equipment of power systems, and the tracking resistance grade is one of the indicators used for evaluating the performance of silicone rubber. It is of great significance to quickly detect the tracking resistance of insulator materials on site. The existing tracking resistance tests are all laboratory tests performed after sample preparation, and there is a lack of on-site detection methods. The laser-induced breakdown spectroscopy (LIBS) method was used to establish the linear relationship between the amount of ablation due to tracking and the background radiation intensity of the experimental LIBS spectrum, and the influence of silica and alumina trihydrate (ATH) fillers on the material’s tracking resistance was studied. This study showed that the LIBS technology can be used to detect the tracking resistance of silicone rubber materials.

Pyruvate decarboxylase (PDC), a key enzyme in alcoholic fermentation in Saccharomyces cerevisiae, can degrade pyruvic acid to further convert acetaldehyde into ethanol. The main structural genes encoding PDC are PDC1 and PDC5. In this study, metabolic engineering principles were used to block the further metabolism of pyruvic acid; Saccharomyces cerevisiae Y2-1 with PDC1 disruption and Y2-15 with both PDC1 and PDC5 disruption were obtained using the LiAc/SS carrier DNA/PEG method. The specific PDC activity of mutant S. cerevisiae Y2-1 decreased by 31 % compared to that of the parent strain Y2, while specific PDC activity was barely detectable in mutant S. cerevisiae Y2-15. Moreover, the mutant Y2-1 with PDC1 disruption displayed no obvious effect on the rate of growth in the yeast nitrogen base with glucose (YNBG) medium, but the growth rate of S. cerevisiae Y2-15 was significantly lower than that of the parent strain Y2. Finally, through optimization of the fermentation medium, the accumulation of pyruvic acid by Y2-15 increased to 24.65 g/L over a period of 96 h, 16.86-fold higher than with the parental strain Y2 by shake flask cultivation.

A new, metal-free method for the formation of C(sp3)–O bonds was established by PhI(OAc)2-mediated oxygenation of benzylic C(sp3)–H bonds with N-hydroxyamides at room temperature, in which the C(sp3)–H oxidation is activated by a polyflurophenylamide group.

Hydrogenotrophic methanogenesis has been proved to be a feasible biological method for biogas upgrading. To improve its performance, the feasibility of typical anaerobic granules as the inoculum was investigated in both batch and continuous experiments. The results from batch experiments showed that glucose-acclimated granules seemed to perform better than granules acclimated to acidified products (AP, i.e. acetate, propionate and ethanol) in in situ biogas upgrading systems and a slightly higher H2 consumption rate (1.5 mmol H2 g VSS(-1) h(-1)) was obtained for glucose-acclimated granules. For AP-acclimated granules, the inhibition on anaerobic digestion and pH increase (up to 9.55±0.16) took place, and the upgrading performance was adversely affected. In contrast, better performance for AP-acclimated granules was observed in ex situ systems, possibly due to their higher hydrogenotrophic methanogenic activities (HMA). Moreover, when gas-liquid mass transfer limitations were alleviated, the upgrading performance was significantly improved (three-fold) for both glucose-acclimated and AP-acclimated granules. The HMA of anaerobic granules could be further enhanced to improve biogas upgrading performance via continuous cultivation with H2/CO2 as the sole substrate. During the three months' cultivation, secondary granulation and microbial population shift were observed, but anaerobic granules still remained intact and their HMA increased from 0.2 to 0.6 g COD g VSS(-1) d(-1). It indicated that the formation of hydrogenotrophic methanogenic granules, a new type of anaerobic granules specialized for high-rate hydrogenotrophic methanogenesis and biogas upgrading, might be possible. Conclusively, anaerobic granules showed great potential for biogas upgrading.

Inhibition of the phosphoinositide 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling pathway by PI3K/mTOR dual inhibitors provides a promising new approach to the treatment of cancers. In this Letter, we identified structurally novel and potent PI3K/mTOR dual inhibitors from a series of 2-amino-4-methylpyrido[2,3-d]pyrimidine derivatives. Their synthesis and structure–activity relationships are reported.

Reactive extrusion method is used to synthesizing LiMg x Fe 1− x PO 4 /C, using LiOH⋅H 2 O, FeC 2 O 4 ⋅2H 2 O, P 2 O 5 and nano-MgO as raw materials and glucose as carbon source. Samples are investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), TG–DTA analysis and electrochemical performance test. Results show that amorphous product can be achieved after the reactive extrusion process. The particle size increases with the increase of magnesium content. Appropriately Mg 2+ doping can reduce the electrode polarization effectively without seriously effect on material structure and morphology. LiMg 0.04 Fe 0.96 PO 4 /C, showing the best electrochemical performances, has an initial discharge capacity of 155, 148, 140 and 137 mA h g −1 at 0.2 C, 0.5 C, 1 C and 2 C rate, respectively. The discharge capacities remain above 99% after 20 cycles.

Copper-catalyzed amidation of acids with formamides or acetamide for the selective synthesis of amides with the aid of 1,4-diazabicyclo[2.2.2]octane as the ligand and tert-butyl hydroperoxide as the oxidant is presented. This method is highly compatible with a wide range of acids, including alkyl acids, aryl acids, α,β-unsaturated acids, and amino acids.

A practical and straightforward access to pyrazolo[3,4-c]quinolines by molecular sieve mediated dehydrogenative [2 + 2 + 1] heteroannulation of N-(o-alkenylaryl)imines with aryldiazonium salts is described using a sp3-hybrid carbon atom as a one-carbon unit. The reaction enables the formation of three new chemical bonds, a C–C bond and two C–N bonds, in a single reaction and features simple operation and excellent functional group tolerance.

A practical and straightforward access to pyrazolo[3,4-c]quinolines by molecular sieve mediated dehydrogenative [2 + 2 + 1] heteroannulation of N-(o-alkenylaryl)imines with aryldiazonium salts is described using a sp(3)-hybrid carbon atom as a one-carbon unit. The reaction enables the formation of three new chemical bonds, a C-C bond and two C-N bonds, in a single reaction and features simple operation and excellent functional group tolerance.

A metal-free radical-mediated [4+2] annulation of internal arylalkynes with tert-butyl nitrite (t-BuONO) is presented for the synthesis of benzo[e][1,2]oxazin-4-ones through the addition of t-BuONO across the C C triple bond, hydration, isomerization and aromatic C(sp(2)) H oxidation cascades. The O-18-labeling experiment shows that two oxygen atoms in the product system are from water.

An efficient and resuble copper on iron catalyst has been prepared for the cleavage of the carbon-carbon o-bond in α-aminocarbonyl compounds leading to the corresponding formylamides and acids with a maximal TON of up to 51,000. It is noteworthy that the copper on iron catalyst can be easily separated from the reaction mixture, and retains its activity after several reuses.

A new oxidative coupling of unactivated terminal alkenes with amides using peroxides is described, in which mono- and difunctionalization of alkenes are selectively achieved. In this reaction with amides, the chemoselectivity toward the functionalization of the C(sp(3))-H bonds adjacent to the nitrogen atom or the functionalization of the carbonyl C(sp(2))-H bonds across alkenes relies on the reaction conditions.

Mono- and difunctionalization of a broad scope of non-activated alkenes is achieved with excellent chemoselectivities by a new oxidative coupling method.

We describe here a new metal-free route for the synthesis of 3-nitroindoles by the nitrative cyclization of N-aryl imines with tert-butyl nitrite. The radical transformation allows the assembly of the indole framework through oxidative cleavage of multi C–H bonds, a nitration, cyclization and isomerization cascade.

Two complexes [PyH][Ni(Mnt)2] (I) and [QlH][Ni(Mnt)2] (II) (Mnt2– = maleonitriledithiolate, [PyH]+ = pyridinium, [QlH]+ = quinolinium) were synthesized and characterized by elemental analysis and IR spectra. ESR spectra of polycrystalline samples collected at room temperature are isotropic with g = 2.039 for Iand anisotropic with g z = 1.997, g y ≈ g x = 2.102 (g av = 2.068) for II. The magnetic susceptibility data of I and II have been measured in the temperature range of 2–300 K. The results obtained suggest the antiferromagnetic coupling interactions between neighboring Ni3+ ions for I and ferromagnetic coupling interactions for II, respectively. Based on the crystal structure analysis of I, the magnetic properties of two complexes were discussed.

A novel route to Δ(2)-isoxazolines is presented via silver-mediated radical cyclization of α-halo ketoximes with 1,3-dicarbonyl compounds. This method is performed using a radical strategy, and represents a new example of silver-initiated generation of oxime radicals for the formation of the C(sp(3))-O bonds.

Various different functionalized alkynes can be methylated through a C(sp)—C(sp3) bond formation process.

Copper-catalyzed amidation of acids with formamides or acetamide for the selective synthesis of amides with the aid of 1,4-diazabicyclo[2.2.2]octane as the ligand and tert-butyl hydroperoxide as the oxidant is presented. This method is highly compatible with a wide range of acids, including alkyl acids, aryl acids, α,β-unsaturated acids, and amino acids.

A novel palladium-catalyzed methylation protocol for the synthesis of methyl-functionalized internal alkynes has been established. This methylation method is achieved through a C(sp)-C(sp(3)) bond formation process and represents a new synthetic application of sulfonium ylides.

Effect of calcium on the solubility of zinc oxide in the sodium hydroxide solution was studied in this paper. Results showed that ZnO equilibrium concentration was different at different temperatures when CaO or Ca(OH)2 was added to the saturated sodium zincate solution of Na2O-ZnO-H2O system. ZnO equilibrium concentrations had little change with Ca(OH)2 added at 100°C. But the concentrations became complicated at the temperature of 25°C, 50°C and 75°C, which decreased at Na2O ≤ 20% and then had no change at Na2O > 20% with Ca(OH)2 added at 25°C, 50°C and 75°C. The curves of the decreased equilibrium concentration formed arc shape when CaO or Ca(OH)2 added. Moreover, the curves of the concentration added CaO more crooked than that added Ca(OH)2. The dissociated Ca from Ca(OH)2 bonded to oxygen of ZnO22- and produced calcium zincate precipitation(Ca(Zn(OH)3)2•2H2O), which leads to zinc loss in the solution and decreases the balance concentration of zinc oxide. Therefore, in order to avoid the loss of zinc when CaO or Ca(OH)2 added to sodium zincate solution, Na2O concentration would be controlled above 20% or temperature be about 100°C.

The substitution pattern at the indan products depends on the phosphine ligand in conditions A) or B).

A selective protocol for the synthesis of 2-methylene-3-substituted-2,3-dihydro-1H-inden-1-ones and 2-benzylidene-2,3-dihydro-1H-inden-1-ones has been developed via palladium-catalyzed cyclocarbonylation reactions of arynes with allyl carbonates and carbon monooxide (CO). It is noteworthy that the selectivity of this new route is depended on both substrates and ligands.

A series of waterborne polyurethane(WPU) dispersions with different molar ratio of —NCO to —OH(n(—NCO)/n(—OH)) were synthesized using tetramethyl xylene diisocyanate(TMXDI),polyester diol and dimethylolpropionic acid as raw materials.The effect of n(—NCO)/n(—OH) on the properties of WPU was investigated.The experiment results showed that with the increase of n(—NCO)/n(—OH),the particle size increased while the particle size distribution became wider;the crystallinity,thermostability and the water resistance tend to decrease as well.When n(—NCO)/n(—OH) was 3.0,the particle size of WPU based TXMDI was fallen in the range of 10 to 30 nm,the decomposition temperature and 24 h water absorption of WPU film were 275 ℃ and below 10%,respectively.