Glucose-derived solid acids and their stability enhancement for upgrading biodiesel via esterification

Utilization of biomass-derived materials or chemicals plays a significant role in reducing the dependence of unsustainable resources of petroleum and coal. A series of sulfonated glucose-derived solid acids(SGSAs) were developed in this study through a one-step method. These catalysts were characterized by XRD, FT-IR, SEM,and BET to determine their physiochemical properties, and their acid content was measured by acid–base titration. The catalytic performances of SGSA catalysts were evaluated in two esterification reactions: propionic acid or oleic acid with methanol(a typical reaction to upgrade biodiesel). Conversion of oleic acid and selectivity of methyl oleate can reach as high as 93.3% and 94.7% respectively over SGSA-6, which has the highest -SO3 H density. Moreover, regeneration of spent catalysts by sulfuric acid solution can significantly enhance their stability and reusability.

Selective photocatalytic reduction of CO2 to CO mediated by a[FeFe]-hydrogenase model with a 1,2-phenylene S-to-S bridge

Photocatalytic reduction of CO2 to CO is a promising approach for storing solar energy in chemicals and mitigating the greenhouse effect of CO2.Our recent studies revealed that[(μ-bdt)Fe2(CO)6](1,bdt=benzene-1,2-dithiolato),a[FeFe]-hydrogenase model with a rigid and conjugate S-to-S bridge,was catalytically active for the selective photochemical reduction of CO2 to CO,while its analogous complex[(μ-edt)Fe2(CO)6](2,edt=ethane-1,2-dithiolato)was inactive.In this study,it was found that the turnover number of 1 for CO evolution reached 710 for the 1/[Ru(bpy)3]2+/BIH(BIH=1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]-imidazole)system under optimal conditions over 4.5 h of visible-light irradiation,with a turnover frequency of 7.12 min−1 in the first hour,a high selectivity of 97%for CO,and an internal quantum yield of 2.8%.Interestingly,the catalytic selectivity of 1 can be adjusted and even completely switched in a facile manner between the photochemical reductions of CO2 to CO and of protons to H2 simply by adding different amounts of triethanolamine to the catalytic system.The electron transfer in the photocatalytic system was studied by steady-state fluorescence and transient absorption spectroscopy,and a plausible mechanism for the photocatalytic reaction was proposed.

Dietary saccharin sodium supplementation improves the production performance of dairy goats without residue in milk in summer

The purpose of this study was to investigate the effects of dietary saccharin sodium supplementation on production performance,serum biochemical indicators,and rumen fermentation of dairy goats in summer.Twelve Guanzhong dairy goats with similar body weight,days in milk,and milk yield were randomly divided into two dietary treatments:(1)CON:basal diet;(2)SS:basal diet+150 mg/kg saccharin sodium on the basis of dry matter.The experiment lasted 35 d,including 7 d for adaptation and 28 d for dietary treatments,sampling and data collection.Each dairy goat was housed individually in a clean separate pen with ad libitum access to diet and water.The goats fed SS diet had increased dry matter intake(DMI;P=0.037),4%fat corrected milk yield(P=0.049),energy corrected milk yield(P=0.037),milk protein yield(P=0.031),and total solids yield(P=0.036).Serum activity of aspartate aminotransferase(P=0.047)and concentrations of 70-kDa heat shock protein(P=0.090),malondialdehyde(P=0.092),and total protein(P=0.057)were lower in goats fed SS diet than those fed CON diet.Supplementation of saccharin sodium tended to increase activity of glutathione peroxidase in serum(P=0.079).The concentrations of rumen total volatile fatty acid(P=0.042)and butyrate(P=0.038)were increased by saccharin sodium supplementation.Dietary supplementation of saccharin sodium increased the relative abundance of Lachnobacterium(P=0.022),Pseudoramibacter(P=0.022),Shuttleworthia(P=0.025),and Syntrophococcus(P=0.037),but reduced the relative abundance of Prevotella_1(P=0.037)and Lachnospiraceae_UCG_008(P=0.037)in rumen.Saccharin sodium was observed in feces and urine of goats fed diet supplemented with saccharin sodium,but saccharin sodium was undetectable in the milk of goats receiving SS diet.In conclusion,administration of saccharin sodium was effective in increasing fat and energy corrected milk yield by increasing DMI and improving rumen fermentation and antioxidant capacity of dairy goats in summer.In addition,saccharin sodium residue was undetectable in the milk.

2.5-dimension soil seismic response to oblique incident waves based on exact free-field solution

With the three dimensional(3D)oblique incident waves exactly determined for the free field,the soil seismic responses in both frequency and time domains are studied by the 2.5 dimension(2.5D)finite/infinite element method.First,the free-field responses in frequency domain are solved exactly for 3D arbitrary incident P and SV waves,which requires no coordinate conversion or extra effort for SV waves with super-critical incident angles.Next,the earthquake spectra are incorporated by the concept of equivalent seismic forces on the near-field boundary,based only on the displacements input derived for unit ground accelerations of each frequency using the 2.5D approach.For the asymmetric 2.5D finite/infinite element model adopted,the procedure for soil seismic analysis is presented.The solutions computed by the proposed method are verified against those of Wolf’s and de Barros and Luco’s and for inversely calculated ground motions.Of interest is that abrupt variation in soil response occurs around the critical angle on the wave propagation plane for SV waves.In addition,the horizontal displacements attenuate with increasing horizontal incident angle,while the longitudinal ones increase inversely for 3D incident P and SV waves.

Seismic analysis of underground tunnels subjected to 3D oblique incident P and SV waves by 2.5D approach

This paper presents,for the first time,the consideration of three-dimensional(3D)oblique incident P and SV waves in calculating the 3D seismic response of a lined tunnel embedded in a half-space by the 2.5D finite/infinite element method(FIEM).Firstly,the applicability of the 2.5D FIEM for 3D seismic analysis is summarized.With the exact solutions obtained for the free field in the Appendix,the equivalent seismic forces are rationally computed for the near-field boundary,considering the horizontal and vertical excitations of the Chi-Chi Earthquake.By performing seismic analysis of the half space embedded with a tunnel using the 2.5D FIEM,the time-domain responses of the tunnel are obtained.The accuracy of the present solutions is verified against those of de Barros and Luco.Conclusions drawn from the parametric study include:(1)Stress concentration for the principal stress under oblique incident seismic waves occurs at the polar angles of 0(vault),90,180(inverted arch),and 270of the lining wall.(2)The vault and inverted arch are the weakest parts of the tunnel during earthquakes.(3)The accelerations of the tunnel during earthquakes can be regarded as of the rigid body type.(4)The responses of the tunnel lining caused by SV waves of an earthquake are much more critical than those by P waves.(5)For arbitrary seismic waves,the maximum longitudinal acceleration azmax is of the same order of magnitude as the maximum horizontal acceleration axmax.

Soil seismic analysis for 2D oblique incident waves using exact free-field responses by frequency-based finite/infinite element method

The seismic analysis of a viscoelastic half-space under two-dimensional(2D)oblique incident waves is carried out by the finite/infinite element method(FIEM).First,the frequency-domain exact solutions for the displacements and stresses of the free field are derived in general form for arbitrary incident P and SV waves.With the present formulation,no distinction needs to be made for SV waves with over-critical incident angles that make the reflected P waves disappear,while no critical angle exists for P waves.Next,the equivalent seismic forces of the earthquake(Taft Earthquake 1952)imposed on the near-field boundary are generated by combining the solutions for unit ground accelerations with the earthquake spectrum.Based on the asymmetric finite/infinite element model,the frequency-domain motion equations for seismic analysis are presented with the key parameters selected.The results obtained in frequency and time domain are verified against those of Wolf’s,Luco and de Barros’and for inversely computed ground motions.The parametric study indicated that distinct phase difference exists between the horizontal and vertical responses for SV waves with over-critical incident angles,but not for under-critical incident angles.Other observations were also made for the numerical results inside the text.

Traditional Chinese medicine mediated tumor suppression via regulating psychological factors

Chronic psychological stress causes physiological stress and leads to disturbance in the body's internal environment.There is growing evidence that stress can promote cancer biological processes,including proliferation,genomic instability,angiogenesis,metastasis,immune evasion,and metabolic disorders,through neuroendocrine mechanisms,immune and inflammatory responses,and epigenetic alterations,and may even impact tumor therapy.In addition,as the tumor development process advances,the body also promotes depressive and anxietylike behaviors through one or more of these mechanisms,generating a vicious cycle that contributes to the tumor's poor prognosis.However,psychosomatic behavioral interventions(PBI)and Chinese medicine can also effectively mitigate the effects of stress in cancer patients.In this review,we will explore the potential pathways of stresstumor interactions.