Attempts to create metal-organic frameworks (MOFs) with zeolitic topologies, metal (zinc(II) and cobalt(II)) imidazolates have repeatedly been used as the metal-organic motifs of inorganic silicate analogues. By modulating the synthetic strategy based on the solvothermal and liquid diffusion method, seven further MOFs (including at least three zeolitic MOFs) of zinc(II) imidazolates, [Zn(im)2.x G] (G=guest molecule, x=0.2-1) 1 a-7 a, have been successfully synthesized. Of these, 1 a-3 a are isostructural with the previously reported cobalt analogues 1 b-3 b, respectively, while 4 a-7 a are new members of the metal imidazolate MOF family. Complex 4 a exhibits a structure related to silicate CaAl2Si2O8 of CrB4 topology, but with a higher network symmetry; complex 5 a has a structure with zeolitic DFT topology that was discovered in zeolite-related materials of DAF-2, UCSB-3, and UCSB-3GaGe; complex 6 a demonstrates an unprecedented zeolite-like topology with one dimensional channels with 10-rings; and 7 a displays a structure of natural zeolite GIS (gismondine) topology. All of these polymorphous MOFs were created only by using certain solvents as structure-directing agents (SDAs). Further extensive metal-organic frameworks with zeolitic topologies can be envisaged if other solvents were to be used.

The objectives of this study were to investigate the effects of different forage-to-concentrate ratios and sampling times on the genetic diversity of carbohydrate-active enzymes (CAZymes) and the taxonomic profile of rumen microbial communities in dairy cows. Six ruminally cannulated Holstein cows were arbitrarily divided into groups fed high-forage (HF) or low-forage (LF) diets. The results showed that, for glycoside hydrolase (GH) families, there were greater differences based on dietary forage-to-concentrate ratio than sampling time. The HF treatment group at 4 h after feeding (AF4h) had the most microbial diversity. Genes that encode GHs had the highest number of CAZymes, and accounted for 57.33% and 56.48% of all CAZymes in the HF and LF treatments, respectively. The majority of GH family genes encode oligosaccharide-degrading enzymes, and GH2, GH3, and GH43 were synthesized by a variety of different genera. Notably, we found that GH3 was higher in HF than LF diet samples, and mainly produced by Prevotella , Bacteroides , and unclassified reads. Most predicted cellulase enzymes were encoded by GH5 (the BF0h group under HF treatment was highest) and GH95 (the BF0h group under LF treatment was highest), and were primarily derived from Bacteroides , Butyrivibrio , and Fibrobacter. Approximately 67.5% (GH28) and 65.5% (GH53) of the putative hemicellulases in LF and HF treatments, respectively. GH28 under LF treatment was more abundant than under HF treatment, and was mainly produced by Ruminococcus , Prevotella , and Bacteroides . This study revealed that HF-fed cows had increased microbial diversity of CAZyme producers, which encode enzymes that efficiently degrade plant cell wall polysaccharides in the cow rumen.

The objectives of this study were to investigate the difference in the mechanism of VFAs production combined with macrogenome technology under different forage-to-concentrate ratios and sampling times. Six ruminally cannulated Holstein cows were used in a randomized complete block design. The high forage (HF) and high concentrate (HC) diets contained 70 and 35% dietary forage, respectively. The results showed that pH was affected by sampling time, at 4 h after feeding had lower value. Excepted for acetate, the VFAs was increased with forage decreased. Propionate formation via the succinic pathway, in which succinate CoA synthetase (EC 6.2.1.5) and propionyl CoA carboxylase (EC 2.8.3.1) were key enzymes, and significantly higher in HC treatment than in HF treatment, Selenomonas, Ruminobacter, Prevotella, and Clostridium were the main microorganism that encodes these key enzymes. Butyrate formation via the succinic pathway, in which phosphate butyryltransferase (EC 2.3.1.19), butyrate kinase (EC 2.7.2.7) and pyruvate ferredoxin oxidoreductase (EC 1.2.7.1) are the important enzymes, Prevotella and Bacteroides played important role in encodes these key enzymes. This research gave a further explanation on the metabolic pathways of VFAs, and microorganisms involved in VFAs production under different F:C ration, which could further reveal integrative information of rumen function.

A novel and effective method was described in this work to prepare two-dimensional hexagonally ordered mesoporous CMK-5 carbon materials. This method is based on the chemical vapor deposition (CVD) of ferrocene in the mesopores of SBA-15 at 500 °C, followed by graphitization at different temperatures. Both the silica/carbon composite and the resulting CMK-5 were characterized by N 2 adsorption, powder X-ray diffraction, Raman spectroscopy, transmission electron microscopy, high-resolution transmission electron microscopy (HRTEM), and thermogravimetric analysis. It was found that the ferrocene could be used as a new precursor to prepare CMK-5 nanopipes, with pipe thicknesses varying from 0.8 to 2.6 nm, by increasing the CVD time from 20 to 120 min. The resulting CMK-5 exhibits high Brunauer-Emmett-Teller (BET) surface area (1044-2449 m 2 /g) and large pore volume (1.13-2.20 cm 3 /g). The graphitization degree of the resulting CMK-5 was investigated by pyrolyzing the corresponding silica/carbon composite at different temperatures. Pyrolysis temperatures below 850 °C led to gradually improved graphitization degrees of CMK-5 nanopipes. Pyrolysis temperatures above 850 °C resulted in the partial collapse of ordered CMK-5 nanopipes accompanied by the appearance of a considerable amount of entangled graphitic ribbons. The structural evolution process of CMK-5 from ordered nanopipes to the final entangled graphitic ribbons was observed by HRTEM. The obtained CMK-5 was applied as a catalyst support of Pt for methanol oxidation. The electrochemical activities of Pt nanoparticles loaded on the CMK-5 carbon materials were investigated by cyclic voltammograms and compared with the commercial Pt/Vulcan XC-72 catalyst. It was found that the specific mass activity of Pt/CMK-5 was much higher than Pt/Vulcan XC-72.