Deep eutectic solvent extraction of myricetin and antioxidant properties.

In this study, a response surface method (RSM) was used to optimise the ultrasonic-assisted deep eutectic solvent (DES) extraction of myricetin from myricetin leaves. The results demonstrated that the DES-5 (choline chloride-oxalic acid) system exhibited better extraction results than the other seven DESs prepared. The optimum extraction conditions for myricetin were a DES-5 system with 19% water content of DES, a liquid-to-solid ratio of 37 : 1 mL g-1, an extraction time of 45 min, and an extraction temperature of 72 °C. Under these conditions, the extraction amount of myricetin was 22.47 mg g-1. To optimise the extraction process, the crude myricetin extract was purified, and the optimal conditions were as follows: an AB-8 macroporous adsorption resin was used with an anhydrous ethanol desorption agent. The adsorption rate was 1 BV per h (bed volume per hour), the desorption rate was 1 BV per h, and the desorption capacity was 2 BV (bed volume). The antioxidant properties of the myricetin were also investigated. The results demonstrated that, with an increase in concentration, the scavenging rates of DPPH and ˙OH free radicals increased. Compared to Vc, myricetin had a better scavenging ability for DPPH free radicals, whereas purified myricetin had a better antioxidant effect. At the same concentration, the radical-scavenging rate of the ˙OH radical was slightly higher in myricetin purified by the macroporous adsorption resin than in Vc, and that of the unpurified myricetin was the smallest. Myricetin was purified using a macroporous adsorption resin to improve its antioxidant properties.

Detection of key gene InDels in JAK/STAT pathway and their associations with growth traits in four Chinese sheep breeds.

OBJECTIVE: The Janus kinase/signal transducer and transporter activator (JAK/STAT) signaling pathway plays crucial roles in lipid metabolism, glucose metabolism and cell senescence, suggesting that they are potential candidate genes affecting growth traits in animals. The present study aimed to evaluate the association between InDels in the JAK/STAT pathway and growth traits of four Chinese sheep breeds, including Tong sheep, Hu sheep, Small-tailed Han sheep and Lanzhou fat-tailed sheep. RESULTS: Seventy-six indel loci of 11 genes in JAK/STAT were detected, and three genotypes were selected at four loci by PCR amplification, electrophoresis and sequencing, including one locus in STAT3, one locus in STAT5A, and two loci in JAK1. The Correlation analysis indicated that there was no significant correlation between STAT3 and growth traits in four sheep breeds (P > 0.05); STAT5A was significantly associated with body height, rump width and tube circumference in Hu sheep and body length in Tong sheep (P < 0.05); JAK1 was significantly correlated with body height, body oblique length, cross height and tube circumference in Hu sheep (P < 0.05) and body oblique length, cross height and tube circumference in small-tailed Han sheep (P < 0.05). CONCLUSION: Overall, our results indicated a potential association between the growth traits of sheep and the InDels of JAK1 and STAT5A.

Controlled Synthesis and Visible-Light-Driven Photocatalytic Activity of BiOBr Particles for Ultrafast Degradation of Pollutants.

For the purpose of regulating the visible-light-driven photocatalytic properties of photocatalysts, we selected BiOBr as the research target and various routes were used. Herein, via the use of a hydrothermal method with various solvents, BiOBr particles with controllable morphology and photocatalytic activities are obtained. In particular, through changing the volume ratio of ethylene glycol (EG) to ethanol (EtOH), BiOBr compounds possess microspheres, in which samples synthesized by using EG:EtOH = 1:2 have the highest photocatalytic activity, and can completely decompose RhB under visible light irradiation within 14 min. Furthermore, we also used different volume ratios of EG and H2O reaction solvents to prepare BiOBr particles so as to further improve its pollutant removal ability. When the volume ratio of EG to H2O is 1:1, the synthesized BiOBr particles have the best photocatalytic activity, and RhB can be degraded in only 10 min upon visible light irradiation. Aside from the reaction solvent, the impact of sintering temperature on the photocatalytic properties of BiOBr particles is also explored, where its pollutant removal capacities are restrained due to the reduced specific surface area. Additionally, the visible-light-triggered photocatalytic mechanism of BiOBr particles is determined by h+, ·OH and ·O2- active species.

Kerr-lens mode-locking of an Yb:CLNGG laser.

We report on a Kerr-lens mode-locked laser based on an Yb3+-doped disordered calcium lithium niobium gallium garnet (Yb:CLNGG) crystal. Pumping by a spatially single-mode Yb fiber laser at 976 nm, the Yb:CLNGG laser delivers soliton pulses as short as 31 fs at 1056.8 nm with an average output power of 66 mW and a pulse repetition rate of ∼77.6 MHz via soft-aperture Kerr-lens mode-locking. The maximum output power of the Kerr-lens mode-locked laser amounted to 203 mW for slightly longer pulses of 37 fs at an absorbed pump power of 0.74 W, which corresponds to a peak power of 62.2 kW and an optical efficiency of 20.3%.

Multiple evaluations of atmospheric behavior between Criegee intermediates and HCHO: Gas-phase and air-water interface reaction.

Given the high abundance of water in the atmosphere, the reaction of Criegee intermediates (CIs) with (H2O)2 is considered to be the predominant removal pathway for CIs. However, recent experimental findings reported that the reactions of CIs with organic acids and carbonyls are faster than expected. At the same time, the interface behavior between CIs and carbonyls has not been reported so far. Here, the gas-phase and air-water interface behavior between Criegee intermediates and HCHO were explored by adopting high-level quantum chemical calculations and Born-Oppenheimer molecular dynamics (BOMD) simulations. Quantum chemical calculations evidence that the gas-phase reactions of CIs + HCHO are submerged energy or low energy barriers processes. The rate ratios speculate that the HCHO could be not only a significant tropospheric scavenger of CIs, but also an inhibitor in the oxidizing ability of CIs on SOx in dry and highly polluted areas with abundant HCHO concentration. The reactions of CH2OO with HCHO at the droplet's surface follow a loop structure mechanism to produce i) SOZ (), ii) BHMP (HOCH2OOCH2OH), and iii) HMHP (HOCH2OOH). Considering the harsh reaction conditions between CIs and HCHO at the interface (i.e., the two molecules must be sufficiently close to each other), the hydration of CIs is still their main atmospheric loss pathway. These results could help us get a better interpretation of the underlying CIs-aldehydes chemical processes in the global polluted urban atmospheres.

Synthesis of renewable diesel and jet fuel range alkanes using 2-methylfuran and cyclohexanone.

New solid acid catalysts were prepared by bisphenol A, paraformaldehyde and chlorosulfonic acid, and applied to hydroxylalkylation/alkylation (HAA) of 2-methylfuran (2-MF) and cyclohexanone. After optimizing the reaction conditions, the conversion of 2-MF reached 99% and the yield of 5,5'-(cyclohexane-1,1-diyl)bis(2-methylfuran) acquired 98%. The activity and catalytic efficiency were higher than those of Amberlyst 15 and Amberlyst 36 resins, which could be rationalized by high acid strength. At the same time, the catalysts were characterized by acid-base titration and FTIR. Hydrodeoxygenation (HDO) of HAA products of 2-methylfuran and cyclopentanone were processed on the Ni/SiO2 catalyst prepared by wet impregnation method to further convert into aviation kerosene, and the yield reached 93%.

Highly efficient continuous-wave and passively Q-switched Yb:YLuGdCOB compact lasers.

Highly efficient operation of an Yb:YLuGdCOB compact laser was demonstrated, producing an output power of 14.30 W around 1054 nm, with an optical-to-optical efficiency of 70.0% and a slope efficiency of 81%. In dual-polarization oscillation in an emission range of 1080 - 1085 nm, 11.37 W of output power was generated with a slope efficiency of 76%. Efficient passively Q-switched operation was also realized by incorporating a 2D MoTe2 saturable absorber into the compact resonator, producing a maximum pulsed output power of 1.56 W at 1030 nm at a repetition rate of 481 kHz; while the largest attainable pulse energy, minimum pulse duration, and highest peak power were, respectively, 3.87 µJ, 26.2 ns, and 147.7 W. The pulse width proves to be the shortest, while the peak power is the highest ever reported for solid-state lasers passively Q-switched with 2D saturable absorbers.

Synthesis of butadiene/isoprene-styrene di-block copolymer with high cis-1,4 unit content based on a neodymium phosphate ester.

A novel two-step synthesis strategy based on a liquid neodymium phosphate ester (Nd(P507)3) catalyst was used to synthesize diene-styrene di-block copolymers with high cis-1,4 unit content, such as butadiene-styrene (PB-b-PS), isoprene-styrene (PI-b-PS), and so on. The strategy not only makes full use of the high cis-1,4 stereo-selectivity of the rare earth catalyst to conjugated dienes, but also adjusts the electron cloud density of the catalytic active center by introducing triphenyl phosphine (PPh3). Thus, the catalytic activity of the neodymium-based catalyst center toward styrene has been largely improved, and a series of PB/PI-b-PSs with high cis-1,4 unit content (98.3 and 98.1% respectively), narrow molecular weight distribution and controllable block ratio were successfully synthesized. Herein, molecular weight (M n), molecular weight distribution (M w/M n) and microstructure of the block polymers were characterized using SEC-MALLS, FT-IR, 1H NMR, 13C NMR and DSC. The DSC curve of a PB-b-PS with 98.3% cis-1,4 unit and 18.6% polystyrene content shows a T g of -103.1 °C, which means it has relatively excellent mechanical properties at lower temperature. The results show that these PB/PI-b-PS materials have good application prospects in harsh low temperature environments.

Mesoporous magnetic g-C3N4 nanocomposites for photocatalytic environmental remediation under visible light.

Mesoporous magnetic Fe3O4/g-C3N4 nanocomposites were synthesized by a facile precipitation method using deionized water as solution. And the prepared magnetic materials were characterized by mean of various detection methods. At the same time, the photocatalytic activity of the synthetic material as photocatalyst under visible light was tested by taking the degradation of rhodamine B in water as a mark. Results show that as-synthesized Fe3O4/g-C3N4 nanocomposites have high specific surface areas of about 5-10.5 times that of pure g-C3N4 and high saturation magnetizations, which can ensure the smooth recovery of used nanomaterials under the action of external magnetic field. The addition of Fe3O4 greatly extents the response range of g-C3N4 nanomaterials to visible light and reduces the recombination rate of photoinduced electron-hole pairs. Meanwhile, the photocatalytic activity of the synthetic materials increases so that the degradation ratio of rhodamine B in water reached 97.6% after 4 h visible light irradiation. Furthermore, prepared magnetic Fe3O4/g-C3N4 nanocomposites have also excellent stability so that the degradation ratio of rhodamine B was almost not reduce after 5 times of continuous reuse of photocatalyst. Free radical scavenging experiments shows that hydroxyl groups are the main free radicals of photocatalytic reaction, peroxyradicals and holes play the secondary role. Therefore, it can be predicted that the synthesized mesoporous magnetic Fe3O4/g-C3N4 nanomaterials will have a broad application prospect in environmental remediation.

Fabrication of CdS-SBA-15 nanomaterials and their photocatalytic activity for degradation of salicylic acid under visible light.

CdS-SBA-15 nanomaterials were synthesized by solvothermal method using cadmium nitrate as cadmium source and thiourea as sulfur source. The properties of as-prepared materials were characterized by means of XRD, FTIR, TEM, XPS, N2 physisorption, UV-Vis DRS and PL spectra, etc. The results show as-synthesized materials have partially ordered mesoporous structure, larger specific surface area, and higher content of CdS and good crystallinity. The combination of SBA-15 and CdS did almost no reduction in the absorption light range of CdS, but greatly increased the photocapacity of the composite. The synergistic effect of CdS and SBA-15 leads to improving the photocatalytic degradation activity of salicylic acid under visible light. When the photocatalyst was 30 mg (0.75 g/L) and the concentration of salicylic acid was 10 mg/L, the maximum degradation efficiency of salicylic acid was 84.93% after 6 h of light. Photocatalytic reaction has a lower activation energy (2.90 kJ/mol), activation enthalpy (3.13 kJ/mol) and activation entropy (-281.00 J/(mol K)). The photocatalytic mechanism study demonstrates that superoxide radicals (O2•-) are the most key active species, e- and h+ have something to do with the photocatalytic reaction, while ·OH has little to do with the photocatalytic reaction. In sum, the protection effect of SBA-15 on CdS nanomaterials makes the composite have a higher photolumination intensity and a higher photocatalytic activity.

Passive Q-switching induced by few-layer MoTe2 in an Yb:YCOB microchip laser.

We report on passive Q-switching action induced by a few-layer MoTe2 saturable absorber in an Yb:YCa4O(BO3)3 (Yb:YCOB) microchip laser. With a sapphire-based few-layer MoTe2 incorporated into the 4 mm long plane-parallel resonator of the Yb:YCOB microchip laser, efficient stable passively Q-switched operation was achieved under output couplings of 40%-70%, producing, at an incident pump power of 5.0 W, an average output power of 1.58 W at a repetition rate of 704 kHz with a slope efficiency of 36%; the pulse energy and peak power were respectively 2.25 µJ and 40.8 W, while the shortest pulse duration obtained was 52 ns.

Fixation of CO2 along with bromopyridines on a silver electrode.

Resulting from the drastic increase of atmospheric CO2 concentration day by day, global warming has become a serious environmental issue nowadays. The fixation of CO2 to obtain desirable, economically competitive chemicals has recently received considerable attention. This work investigates the fixation of CO2 along with three bromopyridines via a facile electrochemical method using a silver cathode to synthesize picolinic acids, which are important industrial and fine chemicals. Cyclic voltammetry is employed to investigate the cyclic voltammetric behaviour of bromopyridines. In addition, systematic study is conducted to study the relationships between the picolinic acids' yield and the electrolysis conditions and intrinsic parameters. The results show that the target picolinic acids' yields are strongly dependent on various conditions such as solvent, supporting electrolyte, current density, cathode material, charge passed, temperature and the nature of the substrates. Moreover, in the studied electrode materials such as Ag, Ni, Ti, Pt and GC, electrolysis and cyclic voltammetry show that Ag has a good electrocatalytic effect on the reduction and carboxylation of bromopyridine. This facile electrochemical route for fixation of CO2 provides an indispensable reference for the conversion and utilization of CO2 under mild conditions.

Multi-watt sub-30 ns passively Q-switched Yb:LuPO4/WS2 miniature laser operating under high output couplings.

We report on a miniature Yb:LuPO4 crystal laser at 1.01 µm that is passively Q-switched with a sapphire-based few-layer WS2 saturable absorber, and that can be operated under very high output couplings (≥80%). With 12.6 W of pump power absorbed, an average output power of 4.35 W is generated at a repetition rate of 1.33 MHz with a slope efficiency of 47%. The maximum pulse energy and highest peak power achieved are 3.41 µJ and 110 W, respectively; while the shortest pulse duration obtained is 28.6 ns. To the best of our knowledge, these results represent the highest output power and shortest pulse duration ever achieved in the 1 µm region from solid-state lasers passively Q-switched by using two-dimensional saturable absorbers.

Few-layer Bi2Te3: an effective 2D saturable absorber for passive Q-switching of compact solid-state lasers in the 1-µm region.

An experimental investigation was carried out to evaluate the potential of few-layer Bi2Te3 topological insulator in use as a saturable absorber for passive Q-switching of compact solid-state lasers in the 1-µm spectral region. By incorporating a sapphire-based few-layer Bi2Te3 sample into a Yb:LuPO4 laser that was formed with a 4-mm plane-parallel resonator, we realized efficient, high-power, high-repetition-rate pulsed laser operation. Depending on the output coupling utilized, single- or dual-wavelength laser action could be achieved. A maximum output power of 5.02 W at 1014.5 nm was produced at a pulse repetition rate of 1.67 MHz, with an optical-to-optical efficiency of 41% and a slope efficiency of 54%; while operating at 1004.9/1012.7 nm, the pulsed laser could produce an output power of 3.94 W at 1.38 MHz, with a pulse duration being as short as 34 ns. The largest pulse energy and highest peak power achieved were 3.0 µJ and 85.3 W. The results demonstrated in our experiment reveal the great potential of the few-layer Bi2Te3 topological insulator in the development of pulsed compact solid-state lasers in the 1-µm region.

Watt-level passively Q-switched Yb:LuPO4 miniature crystal laser with few-layer MoS2 saturable absorber.

We demonstrate a Yb:LuPO4 miniature crystal laser that is formed with a 5 mm long plane-parallel resonator, and is passively Q-switched by a few-layer MoS2 saturable absorber. With 6.53 W of pump power absorbed, an average output power of 2.06 W at 1020.8 nm is generated at a pulse repetition rate of 429 kHz with a slope efficiency of 50%; the resulting pulse energy, duration, and peak power are respectively 4.8 µJ, 83 ns, and 57.8 W. While operating at 1010.5 nm, the laser is capable of producing an average output power of 1.53 W at a repetition rate of 870 kHz, with pulse duration being shortened to 61 ns. These results represent a significant progress in the development of Yb- or Nd-ion lasers passively Q-switched by two-dimensional MoS2.

High-energy passively Q-switched laser operation of Yb:Ca3La2(BO3)4 disordered crystal.

Efficient high-energy passively Q-switched laser operation was demonstrated with Yb:Ca3La2(BO3)4 disordered crystal, producing an average output power of 3.0 W at 1018.7 nm, at a pulse repetition frequency of 5.0 kHz; the resulting pulse energy, duration, and peak power were 600 µJ, 5.3 ns, and 113.2 kW, respectively.

High-energy passively Q-switched operation of Yb:GdCa(4)O(BO(3))(3) laser with a GaAs semiconductor saturable absorber.

High-energy passively Q-switched operation of a Yb:GdCa(4)O(BO(3))(3) laser is demonstrated, with a GaAs crystal plate acting as saturable absorber. An average output power of 1.31 W at 1027 nm is produced at a pulse repetition rate of 1.92 kHz, the resulting pulse energy, duration, and peak power being respectively 0.68 mJ, 9.0 ns, and 75.6 kW. The shortest pulse duration obtained is 4.9 ns; whereas the maximum pulse energy achievable amounts to 0.83 mJ, which proves to be nearly one order of magnitude higher than ever generated from Yb or Nd lasers passively Q-switched by a GaAs saturable absorber.

Acousto-optic Q-switching laser performance of Yb:GdCa(4)O(BO(3))(3)crystal.

We report on the active Q-switching laser performance of Yb:GdCa4O(BO3)3 crystal, demonstrated by employing an acousto-optic Q-switch in a compact plano-concave resonator. Stable repetitively Q-switched operation is achieved with pulse repetition rates varying from 30 to 0.2 kHz, producing an average output power of 10.2 W at 1027.5 nm at 30 kHz of repetition rate, with an optical-to-optical efficiency of 30%. The maximum pulse energy generated at the lowest repetition rate of 0.2 kHz is 4.75 mJ, with a pulse width being 11 ns, gives rise to a peak power that amounts to 432 kW.

High-power passively Q-switched Yb:YCa4O(BO3)3 laser with a GaAs crystal plate as saturable absorber.

We report on efficient high-power passively Q-switched operation of a Yb:YCa4O(BO3)3 laser with a GaAs crystal plate acting as the saturable absorber. An average output power of 5.7 W at 1032 nm is generated at a pulse repetition rate of 166.7 kHz when the incident pump power is 26.8 W, with a slope efficiency determined to be 24.5%. The averaged pulse energy achieved is roughly 30 µJ and is increased to about 40 µJ when the output coupling used changes from 30% to 50%, while the shortest pulse width is measured to be 153 ns.

Spectroscopic properties and continuous-wave laser operation of Yb:LuPO4 crystal.

For the first time, and to the best of our knowledge, we report a continuous-wave (cw) laser operation of Yb:LuPO4 crystal, demonstrated at room temperature in a compact plano-concave resonator end pumped by a diode laser. 1.61 W of cw output power around 1039 nm were generated with 2.40 W of pump power at 976 nm absorbed in a 0.3 mm thick crystal, leading to an optical-to-optical efficiency of 67%, whereas the slope efficiency was 75%. Polarized absorption and emission cross-section spectra are also presented and discussed in detail.