•Hydrogels synthesized from microcrystalline cellulose (MCC) and acrylamide (AAm) and acrylic acid (AA).•Synergy between AA, AAm and MCC enhanced adsorption of Cu (II), Pb (II) and Cd (II).•The metal ...ions attached to functional groups and formed chelate compounds.
Modified cellulose hydrogels were prepared by blending and cross-linking with acrylamide and acrylic acid. The structure of hydrogels was characterized and analyzed with fourier transform infrared spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Under the optimized conditions, the maximum absorption capacity in modified cellulose hydrogels of Cu (II), Pb (II) and Cd (II) ions were 157.51, 393.28 and 289.97 mg/g, respectively. In addition, the metal ion adsorption process accorded with pseudo-second-order rate equation and Langmuir adsorption isotherm. Based on the microstructure analysis and adsorption kinetics, the adsorption mechanisms such as physical, chemical, and electrostatic interactions are discussed. The adsorption process was controlled by the ion-exchange mechanism.
The construction of exceptionally robust and high-quality semiconductor–cocatalyst heterojunctions remains a grand challenge toward highly efficient and durable solar-to-fuel conversion. Herein, ...novel graphitic carbon nitride (g-C3N4) nanosheets decorated with multifunctional metallic Ni interface layers and amorphous NiS cocatalysts were fabricated via a facile three-step process: the loading of Ni(OH)2 nanosheets, high-temperature H2 reduction, and further deposition of amorphous NiS nanosheets. The results demonstrated that both robust metallic Ni interface layers and amorphous NiS can be utilized as electron cocatalysts to markedly boost the visible-light H2 evolution over g-C3N4 semiconductor. The optimized g-C3N4-based photocatalyst containing 0.5 wt % Ni and 1.0 wt % NiS presented the highest hydrogen evolution of 515 μmol g–1 h–1, which was about 2.8 and 4.6 times as much as those obtained on binary g-C3N4-1.0%NiS and g-C3N4-0.5%Ni, respectively. Apparently, the metallic Ni interface layers play multifunctional roles in enhancing the visible-light H2 evolution, which could first collect the photogenerated electrons from g-C3N4, and then accelerate the surface H2-evolution reaction kinetics over amorphous NiS cocatalysts. More interestingly, the synergetic effects of metallic Ni and amorphous NiS dual-layer electron cocatalysts could also improve the TEOA-oxidation capacity through upshifting the VB levels of g-C3N4. Comparatively speaking, the multifunctional metallic Ni layers are dominantly favorable for separating and transferring photoexcited charge carriers from g-C3N4 to amorphous NiS cocatalysts owing to the formation of Schottky junctions, whereas the amorphous NiS nanosheets are mainly advantageous for decreasing the thermodynamic overpotentials for surface H2-evolution reactions. It is hoped that the implantation of multifunctional metallic interface layers can provide a versatile approach to enhance the photocatalytic H2 generation over different semiconductor–cocatalyst heterojunctions.
Eu/BiVO(4) composite photocatalysts have been hydrothermally synthesized and characterized by XRD, XPS, SEM, EDS and DRS techniques. The photocatalytic activities of these catalysts were evaluated by ...the decolorization of methyl orange in aqueous solution under visible light irradiation (lambda>420 nm). It proved that the enhanced activities of Eu/BiVO(4) composites are mainly ascribed to the dopants for the effective electron-hole separation effect, and the optimum content of the doped metal can be controlled by adjusting the ratio of the rare materials in precursor.
•FeCl3-catalyzed ethanol pretreatment was developed to recover xylose and glucose.•The enzymatic hydrolysis reached ∼100% after FeCl3-catalyzed ethanol pretreatment.•The enhancement of Tween 80 was ...relevant to lignin content, enzyme dosage, and hydrolysis time.•The addition of Tween 80 reduced cellulase dosage and shorten hydrolysis time.
In this work, a FeCl3-catalyzed organosolv pretreatment was employed at 160 °C to remove hemicellulose and lignin in sugarcane bagasse leaving the cellulose-enriched residue for enzymatic hydrolysis to sugars. The solubilized hemicellulose fractions consisted more monomer xylose than oligomer xylose. The FeCl3-catalyzed organosolv pretreatment significantly improved the enzymatic hydrolysis, nearly 100% of cellulose components were converted to glucose after pretreatment with 0.05 M FeCl3. Structural analysis was employed to reveal how pretreatment affected the enzymatic hydrolysis. With the addition of Tween 80, the same level of glucose was obtained with 50% reduction of enzyme dosage after 24 h. Furthermore, the influence of Tween 80 on different pretreatment systems was investigated, indicating that the improvement was increased as the lignin content increased, decreased with high enzyme loading and extending hydrolysis time. This work suggested that the addition of Tween 80 could improve the enzymatic hydrolysis, reduce the hydrolysis time and enzyme dosage.
In order to avoid the secondary pollution of the toxic residue of chemical crosslinking agent accompanied by chemical hydrogel adsorbent and enhance the adsorption performance of physical hydrogel, ...chitosan/calcium alginate/bentonite (CTS/CA/BT) composite physical hydrogel was constructed. The formation mechanism and structure of the composite hydrogel were determined by FTIR, XRD and SEM. Adsorption performances of the hydrogel toward Pb
, Cu
and Cd
in water under different condition as well as multi-ion competitive sorption were investigated. The adsorption processes were described with the canonical adsorption kinetics and isotherms models. With the utilization of XPS analysis and adsorption thermodynamics analysis, it was found that the adsorptions were spontaneous physico-chemical adsorptions. The results showed that the maximum adsorption capacity of the hydrogel for Pb
, Cu
and Cd
reached up to 434.89, 115.30 and 102.38 mg·g
, respectively, better than those of other physical hydrogels or chitosan/bentonite composite. Moreover, the composite hydrogel improved the collectability of bentonite and showed a good reusability. The modification of bentonite and the formation of hydrogel were completed simultaneously, which greatly simplifies the operation process compared with the prior similar works. These suggest that the CTS/CA/BT composite hydrogel has promising application prospects for removal of heavy metal ions from water.
Plasma homocysteine (Hcy) levels may be associated with all-cause mortality risk. However, the results of this association are conflicting and the dose-response relationship between them has not been ...clearly defined. In this meta-analysis, we conducted a systematic literature search of the PubMed, Embase, Web of Science and Cochrane Library for the relevant articles dated up to February 2017. Pooled relative risks (RRs) and corresponding 95% confidence intervals (CIs) were calculated to evaluate the estimates, and the dose-response relationship was estimated using a restricted cubic spline model. Eleven prospective studies (4,110 deaths among 27,737 individuals) were included. The summary RR of all-cause mortality for the highest Hcy category vs. the lowest Hcy category was 1.80 (95% CI: 1.51, 2.14) with the random effects model. In dose-response meta-analysis, Hcy levels were significantly associated with all-cause mortality risk in a linear fashion (p
= 0.255), and the risk of all-cause mortality increased by 33.6% for each 5 µmol/L increase in Hcy levels (RR = 1.336, 95% CI: 1.254-1.422, p < 0.001). Findings from this dose-response meta-analysis suggest that Hcy levels are linearly and positively associated with risk of all-cause mortality.
Following a previous genome-wide association study (GWAS 1) including 744 cases and 895 controls, we analyzed genome-wide association data from a new cohort of Han Chinese (GWAS 2) with 1,510 ...polycystic ovary syndrome (PCOS) cases and 2,016 controls. We followed up significantly associated signals identified in the combined results of GWAS 1 and 2 in a total of 8,226 cases and 7,578 controls. In addition to confirming the three loci we previously reported, we identify eight new PCOS association signals at P < 5 × 10(-8): 9q22.32, 11q22.1, 12q13.2, 12q14.3, 16q12.1, 19p13.3, 20q13.2 and a second independent signal at 2p16.3 (the FSHR gene). These PCOS association signals show evidence of enrichment for candidate genes related to insulin signaling, sexual hormone function and type 2 diabetes (T2D). Other candidate genes were related to calcium signaling and endocytosis. Our findings provide new insight and direction for discovering the biological mechanisms of PCOS.
Introduction
Promoting crop growth and regulating denitrification process are two main ways to reduce soil N
2
O emissions in agricultural systems. However, how biochar and arbuscular mycorrhizal ...fungi (AMF) can regulate crop growth and denitrification in soils with different phosphorus (P) supplies to influence N
2
O emission remains largely unknown.
Method
Here, an eight-week greenhouse and one-year field experiments biochar and/or AMF (only in greenhouse experiment) additions under low and high P environments were conducted to characterize the effects on wheat (Triticum aestivum L.) growth and N
2
O emission.
Results
With low P supply, AMF addition decreased leaf Mn concentration (indicates carboxylate-releasing P-acquisition strategies), whereas biochar addition increased leaf Mn concentration, suggesting biochar and AMF addition regulated root morphological and physiological traits to capture P. Compared with low P supply, the high P significantly promoted wheat growth (by 16-34%), nutrient content (by 33-218%) and yield (by 33-41%), but suppressed soil N
2
O emissions (by 32-95%). Biochar and/or AMF addition exhibited either no or negative effects on wheat biomass and nutrient content in greenhouse, and biochar addition promoted wheat yield only under high P environment in field. However, biochar and/or AMF addition decreased soil N
2
O emissions by 24-93% and 32% in greenhouse and field experiments, respectively. This decrease was associated mainly with the diminished abundance of N
2
O-producing denitrifiers (nirK and nirS types, by 17-59%, respectively) and the increased abundance of N
2
O-consuming denitrifiers (nosZ type, by 35-65%), and also with the increased wheat nutrient content, yield and leaf Mn concentration.
Discussion
These findings suggest that strengthening the plant-soil-microbe interactions can mitigate soil N
2
O emissions via manipulating plant nutrient acquisition and soil denitrification.
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