γ-CuI from ionic liquid/poly(ionic liquid)s precursors with controllable morphologies and improved photocatalytic performance.

γ-phase copper(I) iodide (abbreviated to CuI hereafter) with different morphologies is realized through a one-step redox process from I-containing ionic liquid (IL) or poly(ionic liquid)s (PILs) precursors at room temperature. The phase composition, morphology, and electronic states of the synthesized CuI samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The resulting CuI products exhibit three different types of morphologies, namely nanocrystals, with an average size of 0.8 ± 0.2 µm, nanoplates, with a thickness of 35.8 ± 0.9 nm, and nanoflowers, with petals with a thickness of 12.2 ± 0.8 nm. Moreover, the as-synthesized CuI samples exhibit gradually diminishing bandgaps and improved photocatalysis performance for the photodegradation of rhodamine B (RhB) under visible light irradiation as the thickness decreases. XPS measurements confirm that IL/PILs coupled to the CuI surface, resulting in a further charge transfer between Cu and I. These results conclusively prove that IL/PILs serve as both the reducing agents and assemble as orientation templates in the formation of the CuI nanostructures, and also successfully mediate the functional properties of the samples by changing the surface electronic structures.

Solar-Driven Hydrogen Generation Catalyzed by g-C3N4 with Poly(platinaynes) as Efficient Electron Donor at Low Platinum Content.

A metal-complex-modified graphitic carbon nitride (g-C3N4) bulk heterostructure is presented here as a promising alternative to high-cost noble metals as artificial photocatalysts. Theoretical and experimental studies of the spectral and physicochemical properties of three structurally similar molecules Fo-D, Pt-D, and Pt-P confirm that the Pt(II) acetylide group effectively expands the electron delocalization and adjusts the molecular orbital levels to form a relatively narrow bandgap. Using these molecules, the donor-acceptor assemblies Fo-D@CN, Pt-D@CN, and Pt-P@CN are formed with g-C3N4. Among these assemblies, the Pt(II) acetylide-based composite materials Pt-D@CN and Pt-P@CN with bulk heterojunction morphologies and extremely low Pt weight ratios of 0.19% and 0.24%, respectively, exhibit the fastest charge transfer and best light-harvesting efficiencies. Among the tested assemblies, 10 mg Pt-P@CN without any Pt metal additives exhibits a significantly improved photocatalytic H2 generation rate of 1.38 µmol h-1 under simulated sunlight irradiation (AM1.5G, filter), which is sixfold higher than that of the pristine g-C3N4.

An integrated approach for enhancing the overall performance of constructed wetlands in urban areas.

Constructed wetlands (CWs) are an important component of the urban matrix and play an essential role in the restoration of urban ecological environments. Although existing studies have mainly focused on the efficiency of technologies for removing pollutants in wastewater, efforts to intensify the overall performance of CWs have not been reported. Here, we propose a novel theoretical scheme for promoting optimal overall performance of CWs through the development of an integrated approach, entailing simulation, evaluation, and optimization strategies for their management. We successfully simulated the water distribution system of the Yanfangdian CW in Beijing, China, applying 42 hydrological parameters within the MIKE 21 software. We further evaluated our simulation results by performing an analytic hierarchy process to calculate performance scores. The back propagation neural network was well trained to quantify the relationship between the hydrological parameters and the overall performance of CW based on its water distribution characteristics and their corresponding scores. Subsequently, a genetic algorithm was applied to determine the hydrological solution. A strategy for optimizing the water level and flow was formulated for improving the ecological, purification and storage performances of the targeted CW along with a flexible strategy for ensuring its proper functioning. Our approach provides a robust and universal platform that can contribute significantly to the advancement of CWs that have a wide range of applications and could be extended to other ecosystems.

Non-precious molybdenum nanospheres as a novel cocatalyst for full-spectrum-driven photocatalytic CO2 reforming to CH4.

Photocatalytic CO2 reforming is considered to be an effective method for clean, low-cost, and environmentally friendly reduction and conversion of CO2 into hydrocarbon fuels by utilizing solar energy. However, the low separation efficiency of charge carriers and deficient reactive sites have severely hampered the efficiency of the photocatalytic CO2 reforming process. Therefore, cocatalysts are usually loaded onto the surface of semiconductor photocatalysts to reduce the recombination of charge carriers and accelerate the rates of surface reactions. Herein, molybdenum (Mo) nanospheres are proposed as a novel non-precious cocatalyst to enhance the photocatalytic CO2 reforming of g-C3N4 significantly. The Mo nanospheres boost the adsorption of CO2 and activate the surface CO2via a photothermal effect. The time-resolved fluorescence decay spectra reveals that the lifetime of photo-induced charge carriers is prolonged by the Mo nanospheres, which guarantees the migration of charge carriers from g-C3N4 to Mo nanospheres. Unexpectedly, Mo loaded g-C3N4 can effectively utilize a wide spectral range from UV to near-infrared region (NIR, up to 800 nm). These findings highlight the potential of Mo nanospheres as a novel cocatalyst for photocatalytic CO2 reforming to CH4.

Ce-Doped Graphitic Carbon Nitride Derived from Metal Organic Frameworks as a Visible Light-Responsive Photocatalyst for H2 Production.

Novel fibrous graphitic carbon nitride (g-C3N4) derivatives prepared from metal organic frameworks (MOFs) were doped with Ce3+ (Ce-C3N4) as photocatalytic materials. Ce-C3N4 was characterized using various techniques, revealing its high specific surface area, excellent photocatalytic activity, and stability for H2 evolution under visible light irradiation. The fluorine modified samples show superior photocatalytic activity under visible light irradiation, which is due to the presence of more active sites and enhanced absorption of solar energy. This work provides a new synthetic route for MOF-derived g-C3N4 that can be doped with different metal ions. The fluorine modified Ce-C3N4 is an efficient photocatalyst with potential for many applications related to energy and the environment.

Multifunctional Zn-Al layered double hydroxides for surface-enhanced Raman scattering and surface-enhanced infrared absorption.

Surface-enhanced Raman scattering (SERS) and surface-enhanced infrared absorption (SEIRA) are complementary techniques, and both provide fingerprint structural information on various materials with a high sensitivity. Herein, Zn-Al layered double hydroxides (LDHs) are proposed for the first time as highly sensitive and uniform substrates for both SERS and SEIRA. Zn-Al LDHs show a remarkable SERS effect with an enhancement factor (EF) as high as 1.637 × 104 by using 4-mercaptobenzoic acid (4-MBA) as the probe molecule, where the charge transfer and hydrogen bonds are believed to result in the SERS effect. Interestingly, Zn-Al LDHs also exhibit SEIRA by using 4-methoxybenzenethiol (4-MTP), where the resultant substrates possess excellent long-term stability. This study not only presents a facile route to fabricate LDH materials, but also provides a novel substrate that can be used in both SERS and SEIRA.

Stannous oxide promoted charge separation in rationally designed heterojunction photocatalysts with a controllable mechanism.

Due to the sluggish mobility of holes, the low charge-separation rate remains an intrinsic issue that limits further increase of the photocatalytic conversion efficiency. Herein, we proposed an in situ hydrothermal method to expedite the charge transfer with enhanced photocatalytic H2 evolution rate and photodegradation activities via introducing SnO microplates into TiO2. As compared to bare TiO2, the SnO/TiO2 heterojunction achieves remarkable 470% and 150% higher efficiency for the photocatalytic H2 evolution rate and photodegradation of rhodamine B, respectively. In particular, it is demonstrated that the charge transfer mechanism of SnO/TiO2 can be switched from the Z-scheme to type II by Pt loading, leading to a significant enhancement of photocatalytic performances. Furthermore, the photocatalytic H2 evolution activities of ZnO and C3N4 can also be improved by introducing SnO via simple mechanical mixing. This work provides not only a new versatile stimulant for enhancing photocatalytic activities but also in-depth understanding of the charge transfer mechanism of heterointerfaces of semiconductors.

Improving the Visible-Light Photocatalytic Activity of Graphitic Carbon Nitride by Carbon Black Doping.

Hydrogen production by water splitting and the removal of aqueous dyes by using a catalyst and solar energy are an ideal future energy source and useful for environmental protection. Graphitic carbon nitride can be used as the photocatalyst with visible light irradiation. However, it typically suffers from the high recombination of carriers and low electrical conductivity. Here, we have developed a facile mix-thermal strategy to prepare carbon black-modified graphitic carbon nitrides, which possess high electrical conductivity, a wide adsorption range of visible light, and a low recombination rate of carriers. With the help of carbon black, highly crystallized graphitic carbon nitrides with built-in triazine and heptazine heterojunctions are obtained. Improved photocatalytic activities have been achieved in carbon black-modified graphitic carbon nitride. The dye removal rate can be three times faster than that of pristine graphitic carbon nitride and the photocatalytic H2 generation is 234 µmol h-1 g-1 under visible light irradiation.

Effects of unsaturated fatty acids on calcium-activated potassium current in gastric myocytes of guinea pigs.

AIM: To investigate the effects of exogenous unsaturated fatty acids on calcium-activated potassium current (I(K(Ca))) in gastric antral circular myocytes of guinea pigs. METHODS: Gastric myocytes were isolated by collagenase from the antral circular layer of guinea pig stomach. The whole-cell patch clamp technique was used to record I(K(Ca)) in the isolated single smooth muscle cells with or without different concentrations of arachidonic acid (AA), linoleic acid (LA), and oleic acid (OA). RESULTS: AA at concentrations of 2,5 and 10 micromol/L markedly increased I(K(ca)) in a dose-dependent manner. LA at concentrations of 5, 10 and 20 micromol/L also enhanced I(K(Ca)) in a dose-dependent manner. The increasing potency of AA, LA, and oleic acid (OA) on I(K(Ca)) at the same concentration (10 micromol/L) was in the order of AA>LA>OA. AA (10 micromol/L)-induced increase of I(K(ca)) was not blocked by H-7 (10 micromol/L), an inhibitor of protein kinase C (PKC), or indomethacin (10 micromol/L), an inhibitor of the cyclooxygenase pathway, and 17-octadecynoic acid (10 micromol/L), an inhibitor of the cytochrome P450 pathway, but weakened by nordihydroguaiaretic acid (10 micromol/L), an inhibitor of the lipoxygenase pathway. CONCLUSION: Unsaturated fatty acids markedly increase I(K(ca)), and the enhancing potencies are related to the number of double bonds in the fatty acid chain. The lipoxygenase pathway of unsaturated fatty acid metabolism is involved in the unsaturated fatty acid-induced increase of I(K(ca)) in gastric antral circular myocytes of guinea pigs.

Effect of actin microfilament on potassium current in guinea pig gastric myocytes.

AIM: To investigate the effect of actin microfilament on potassium current and hyposmotic membrane stretch-induced increase of potassium current in gastric antral circular myocytes of guinea pig. METHODS: Whole-cell patch clamp technique was used to record potassium current in isolated gastric myocyes. RESULTS: When the membrane potential was clamped at -60 mV, an actin microfilament disruptor, cytochanlasin-B(Cyt-B, 20 micromol/L in pipette) increased calcium-activated potassium current (I(K(Ca))) and delayed rectifier potassium current (I(K(V))) to 138.4+/-14.3% and 142.1+/-13.1% respectively at +60 mV. In the same condition, an actin microfilament stabilizer phalloidin (20 micromol/L in pipette) inhibited I(K(Ca)) and I(K(V)) to 74.2+/-7.1% and 75.4+/-9.9% respectively. At the holding potential of -60 mV, hyposmotic membrane stretch increased I(K(Ca)) and I(K(V)) by 50.6+/-9.7% and 24.9+/-3.3% at +60 mV respectively. In the presence of cytochalasin-B and phalloidin (20 micromol/L, in the pipette) condition, hyposmotic membrane stretch also increased I(K(Ca)) by 44.5+/-7.9% and 55.7+/-9.8% at +60 mV respectively. In the same condition, cytochalasin-B and phalloidin also increased I(K(V)) by 23.0+/-5.5% and 30.3+/-4.5% respectively. However, Cyt-B and phalloidin did not affect the amplitude of hyposmotic membrane stretch-induced increase of I(K(Ca)) and I(K(V)). CONCLUSION: Actin microfilaments regulate the activities of potassium channels, but they are not involved in the process of hyposmotic membrane stretch-induced increase of potassium currents in gastric antral circular myocytes of guinea pig.

Comparative study in the effect of C-type natriuretic peptide on gastric motility in various animals.

AIM: To investigate the effect of natriuretic peptides on gastric motility in various animals, and the effect of C-type natriuretic peptide (CNP) on spontaneous contraction of gastric smooth muscle in rat, guinea-pig and human in vitro was compared. METHODS: Spontaneous contraction of gastric smooth muscle was recorded by four channel physiograph. RESULTS: In the guinea-pig and rat gastric antral circular smooth muscle, CNP markedly decreased the amplitude of spontaneous contraction but it didn't affect the frequency, however, the contractile activity was completely inhibited by CNP in gastric antral longitudinal smooth muscle. In the human gastric antral circular and longitudinal smooth musle, CNP completely inhibited spontaneous contraction. In the circular smooth muscle of guinea-pig and rat gastric fundus, CNP obviously decreased the amplitude of spontaneous contraction but it didn't affect the frequency, however, the contractile activity was completely inhibited by CNP in smooth muscle of fundus longitudinal. In the circular and longitudinal smooth muscle of guinea-pig gastric body, CNP at first induced a relaxation and then an increase in amplitude of spontaneous contraction (rebound contraction), but the frequency was not changed. After the circular smooth muscle of gastric body was pretreated with atropine, an M receptor blocker, the rebound contraction was abolished; In circular and longitudinal smooth muscle of rat gastric body, CNP induced a transient and slight relaxation and successively followed by the recovery in amplitude of spontaneous contraction but it also didn't affect the frequency. After the smooth muscle was pretreated with atropine, the transient and slight relaxation was replaced by long term and complete inhibition; The percentage of CNP-induced inhibition was 76.77+/-6.21 % (fundus), 67.21+/-5.32 % (body) and 58.23+/- 6.21 % (antral) in the gastric circular muscle, however, the inhibitory percentage was 100+/-0.00 % (fundus), 68.66+/- 3.55 % (body) and 100+/-0.00 % (antrum) in the gastric longitudinal smooth muscle of guinea-pigs; In the rat, the percentage of CNP-induced inhibition was 95.87+/-4.12 % (fundus), 94.91+/-5.08 % (body) and 66.32+/-7.32 % (antrum)in the gastric circular smooth muscle, but in the longitudinal smooth muscle, CNP completely inhibited the spontaneous contraction. Using LY83583, a guanylate cyclase inhibitor, and zaparinast as a phosphoesterase inhibitor to inhibit the generation of cGMP, the effect of CNP on the spontaneous contraction was markedly weakened by LY83583, however, the inhibitory effect was enhanced by zaparinast. CONCLUSION: (1) CNP can obviously inhibit the spontaneous contraction of gastric antral circular and longitudinal smooth muscle in the rat, guinea-pig and human. The order of inhibitory potency is human >rat> guinea-pig. (2) In the same animals, the inhibitory effect of CNP on spontaneous contraction is the most powerful in fundus and the weakest in antrum, in the same position, the inhibitory effect on the circular smooth muscle is more powerful than that on longitudinal smooth muscle. (3) The inhibitory effect of CNP on spontaneous contraction in the gastric smooth muscle is mediated by a cGMP dependent pathway.

Role of unsaturated fatty acids in the enhancement of muscarinic current by hyposmotic membrane stretch in guinea pig smooth muscle cells.

To investigate the function of exogenous unsaturated fatty acids in hyposmotic membrane stretch enhancement of muscarinic current (ICCh) in antral circular smooth muscle cells of guinea pig, we recorded the membrane current with the conventional whole cell patch-clamp technique. I(CCh) elicited by 50 micromol/L carbachol (CCh) at the holding potential of 20 mV under isosmotic condition was taken as control. Hyposmotic membrane stretch increased I(CCh) to 226.0+/-21.0%. When the cells were pretreated with 5 micromol/L arachidonic acid (AA), linoleic acid (LA) or oleic acid (OA), I(CCh)was inhibited to 3.8+/-0.6%, 35.2+/-0.8% and 66.6+/-0.6% respectively. Hyposmotic membrane stretch increased I(CCh) to 106.0+/-2.5%, 173.2+/-6.8% and 222.1+/-11.0% of the control respectively. Five micromol/L AA inhibited hyposmotic membrane stretch-enhanced I(CCh) by 51.2+/-3.8%, while the control I(CCh) under isosmotic condition was inhibited by 96.2+/-1.6%. The results suggest that unsaturated fatty acids inhibited I(CCh) and the inhibitory effect is more significant when the unsaturation degree is increased. However, the unsaturated fatty acids are not involved in the increase of I(CCh) induced by hyposmotic membrane stretch.

Hyposmotic membrane stretch potentiated muscarinic receptor agonist-induced depolarization of membrane potential in guinea-pig gastric myocytes.

AIM: To investigate the relationship between hyposmotic membrane stretch and muscarinic receptor agonist-induced depolarization of membrane potential in antral gastric circular myocytes of guinea-pig. METHODS: Using whole cell patch-clamp technique recorded membrane potential and current in single gastric myocytes isolated by collagenase. RESULTS: Hyposmotic membrane stretch hyperpolarized membrane potential from -60.0mV+/-1.0mV to -67.9mV+/-1.0mV. TEA (10 mmol/L), a nonselective potassium channel blocker significantly inhibited hyposmotic membrane stretch-induced hyperpolarization. After KCl in the pipette and NaCl in the external solution were replaced by CsCl to block the potassium current, hyposmotic membrane stretch depolarized the membrane potential from -60.0 mV+/-1.0mV to -44.8 mV+/-2.3mV (P<0.05), and atropine (1 micromol/L) inhibited the depolarization of the membrane potential. Muscarinic receptor agonist Carbachol depolarized membrane potential from -60.0mV+/-1.0mV to -50.3 mV+/-0.3mV (P<0.05) and hyposmotic membrane stretch potentiated the depolarization. Carbachol induced muscarinic current (I( cch )) was greatly increased by hyposmotic membrane stretch. CONCLUSION: Hyposmotic membrane stretch potentiated muscarinic receptor agonist-induced depolarization of membrane potential, which is related to hyposmotic membrane stretch-induced increase of muscarinic current.