Alkyl halide/tertiary amine as novel initiators for free radical polymerizations of methyl methacrylate, methyl acrylate and styrene

A series of combinations of alkyl halide with tertiary amine such as ethyl α-bromophenylacetate/tris[2-(dimethylamino)ethyl)]amine (αEBP/Me6TREN), ethyl 2-bromoisobutyrate/triethylamine (EBiB/TEA), and ethyl 2-chloropropionate/N,N,N′,N′,N′′-pentamethyldiethylenetriamine (ECP/PMDETA) have been developed as novel free radical initiators and used for the polymerizations of methyl acrylate (MA), methyl methacrylate (MMA) and styrene (St). The effects of the structure of alkyl halide and tertiary amine on the polymerization of MA were investigated. Gel permeation chromatograph (GPC) and proton nuclear magnetic resonance (1H NMR) have been utilized to analyze the end group of the obtained poly(methyl acrylate). Electron spin resonance (ESR) spectroscopy was employed to identify the structure of the radicals produced by αEBP/Me6TREN, and the results indicated that αEBP reacted with Me6TREN via a single electron transfer (SET) nucleophilic mechanism to produce corresponding ethyl α-phenylacetate radicals which subsequently initiated the polymerization of MA. As both alkyl halide and tertiary amine are commercially available at low cost, non-explosive, and ease of use and storage in comparison with conventional azo, peroxide or persulfate initiators, the combination of alkyl halide and tertiary amine as a free radical initiator is promising for large-scale practical applications.</p

Ni Nanoparticles Inlaid Nickel Phyllosilicate as a Metal–Acid Bifunctional Catalyst for Low-Temperature Hydrogenolysis Reactions

Hydrogenolysis of carbon–oxygen bonds is a versatile synthetic method, of which hydrogenolysis of bioderived 5-hydroxymethylfurfural (HMF) to furanic fuels is especially attractive. However, low-temperature hydrogenolysis (in particular over non-noble catalysts) is challenging. Herein, nickel nanoparticles (NPs) inlaid nickel phyllosilicate (NiSi-PS) are presented for efficient hydrogenolysis of HMF to yield furanic fuels at 130–150 °C, being much superior with impregnated Ni/SiO₂ catalysts prepared from the same starting materials. NiSi-PS also shows a 2-fold HMF conversion intrinsic rate and 3-fold hydrogenolysis rate compared with the impregnated Ni/SiO₂. The superior performance originated from the synergy of highly dispersed nickel NPs and substantially formed acid sites due to coordinatively unsaturated Ni (II) sites located at the remnant nickel phyllosilicate structure, as revealed by detailed characterizations. The model reactions over the other reference catalysts further highlighted the metal–acid synergy for hydrogenolysis reactions. NiSi-PS can also efficiently catalyze low-temperature hydrogenolysis of bioderived furfural and 5-methylfurfural, demonstrating a great potential for other hydrogenolysis reactions

Cu Nanoparticles Inlaid Mesoporous Al₂O₃ As a High-Performance Bifunctional Catalyst for Ethanol Synthesis via Dimethyl Oxalate Hydrogenation

Ethanol synthesis from syngas via dimethyl oxalate (DMO) hydrogenation is of crucial importance for environment- and energy-related applications. Herein, we designed the bifunctional Cu nanoparticle (NP) inlaid mesoporous Al₂O₃ catalyst and first applied it to ethanol synthesis with high efficiency. The catalyst was made based on the spatial restriction strategy by pinning the Cu NPs on mesoporous Al₂O₃ to conquer the sintering problem and facilitate the stability (>200 h at 270 °C), which has potential values in high-temperature and exothermic reactions. The plentiful pores, highly exposed and properly assembled Cu-acid sites, furnished the catalyst with high ethanol yield (∼94.9%). A structure-sensitive behavior that the intrinsic activity increases with the decreasing NP size was discussed. It was attributed to the change in metal–acid interfacial sites, morphology, and electronic structure and balance of surface Cu⁰–Cu⁺ species. The mechanism for DMO hydrogenation to ethanol involving activation of CO, C–O, and O–H bands was also proposed. As cleavage of these bonds is a versatile tool to utilize bioderived molecules (e.g., polyols), the bifunctional catalysts can also be applied to hydrogenolysis of C–O bonds or etherification of O–H groups to produce various chemicals

The Rise of Calcination Temperature Enhances the Performance of Cu Catalysts: Contributions of Support

To develop the high-performance supported metal catalyst for industrial processes, it is highly desirable to elucidate and fully utilize the indispensable support part. Herein, the relationship between catalytic performance and the structure of support ZrO₂ was elucidated by comprehensive analysis of the progressive calcination experiments, tests over model catalysts, and various characterizations of catalyst structures. We demonstrated that combination of Cu and tetragonal ZrO₂ makes a highly active, selective, and especially stable catalyst for the hydrogenation of dimethyl oxalate to ethylene glycol. To obtain stable Cu particles, the catalyst was annealed at high temperatures (e.g., from 450 to 850 °C). The stable large Cu particles were formed, and the number of exposed Cu sites decreased. Fortunately, support ZrO₂ was motivated into the tetragonal phase, compensating for and even improving the activity. Thus, the yield of ethylene glycol was greatly improved from ∼26 to 99%, and a stable performance was achieved (life span of >600 h). The strategy alleviated the dependence of hydrogenation on highly dispersed metal sites and provided an alternative way to enhance the catalytic stability. This simple way simultaneously improved the efficiency and reduced the level of irreversible deactivation due to sintering, which has great potential for industrial applications. Tetragonal ZrO₂ also proved to be effective for a series of carbonyl hydrogenations (e.g., esters, aldehydes, ketones, and acids), indicating a general promotion of these reactions by ZrO₂

Enhanced Nickel-Catalyzed Methanation Confined under Hexagonal Boron Nitride Shells

Encapsulation of metal nanoparticles with porous oxide shells is a successful strategy to design catalysts with high catalytic performance. We suggest an alternative route to cover metal nanoparticles with two-dimensional (2D) material shells such as hexagonal boron nitride (h-BN), in which active metal components are stabilized by the outer shells and meanwhile catalytic reactions occur at interfaces between cores and shells through feasible intercalation of the 2D material covers. As an illustration, Ni nanoparticles encapsulated with few-layer h-BN shells were constructed and applied in syngas methanation. Ni@h-BN core–shell nanocatalysts exhibit enhanced methanation activity, higher resistance to particle sintering, and suppressed carbon deposition and Ni loss in reactions. Surface science studies in h-BN/Ni(111) model systems and chemisorption data confirm the occurrence of methanation reactions on Ni surfaces under h-BN cover. The confinement effect of h-BN shells improves Ni-catalyzed reaction activity and Ni catalyst stability

Differentially expressed gene analysis between siRNA-NC and si-circMEF2A1 transfected SMSCs (fold change > 1.2 and <i>P</i>-value < 0.05).

(A) The volcano plot of the differentially expressed genes between circMEF2A1 knockdown and negative control. (B) The heat map of myogenic marker genes and circMEF2A1/miR-30a-3p target genes in the differentially expressed genes. (TIF)</p

Detection of the knockdown efficiency of different siRNAs.

(A) Knockdown efficiency of three siRNAs against circMEF2A1 analyzed by qRT-PCR, and siRNA-3 was chosen for further analysis and named si-circMEF2A1 in the main documents, n = 3. (B) Knockdown efficiency of three siRNAs against PPP3CA analyzed by qRT-PCR, siRNA-2 was chosen for further analysis and named si-PPP3CA in the main documents, n = 3. (C) Knockdown efficiency of three siRNAs against circMEF2A2 analyzed by qRT-PCR, siRNA-2 was chosen for further analysis and named si-circMEF2A2 in the main documents, n = 3. (D) Knockdown efficiency of three siRNAs against SLIT3 analyzed by qRT-PCR, siRNA-3 was chosen for further analysis and named si-SLIT3 in the main documents, n = 3. (E) Knockdown efficiency of three siRNAs against ROBO2 analyzed by qRT-PCR, siRNA-3 was chosen for further analysis and named si-ROBO2 in the main documents, n = 3. (F) Knockdown efficiency of three siRNAs against MEF2A analyzed by qRT-PCR, siRNA-2 was chosen for further analysis and named si-MEF2A in the main documents, n = 3. (G) Knockdown efficiency of two siRNAs against mmu-circMef2a1 analyzed by qRT-PCR, siRNA-2 was chosen for further analysis and named si-mmu-circMef2a1 in the main documents, n = 3. (H) Knockdown efficiency of two siRNAs against mmu-circMef2a2 analyzed by qRT-PCR, siRNA-1 was chosen for further analysis and named si-mmu-circMef2a2 in the main documents, n = 3. Data were displayed as mean ± SEM, independent sample t-test was used to analyze the statistical differences between each dataset, **P P (TIF)</p

The relation between circMEF2As and MEF2A.

(A) qRT-PCR analysis of linear MEF2A, preMEF2A, circMEF2A1, and circMEF2A2 in the cDNA samples generated from MEF2A siRNA (si-MEF2A) and siRNA-NC transfected SMSCs, n = 3. (B) qRT-PCR analysis of linear MEF2A, preMEF2A, circMEF2A1, and circMEF2A2 in the cDNA samples generated from MEF2A-flag fusion protein overexpression vector (ov-MEF2A-flag) and ov-NC transfected SMSCs, n = 3. (C) Partial MEF2A gene promoter sequences containing MEF2A protein binding site, the chicken MEF2A promoter sequence segment containing wild-type (WT) and mutant-type (MT) of MEF2A protein binding site were subcloned into promoter activity analyze dual-luciferase reporter vector. (D) Dual-luciferase report analysis of empty vector, promoter WT and promoter MT transfected SMSCs, additionally, promoter WT and promoter MT also co-transfected with ov-MEF2A-flag independently, n = 3. (E) Cut & tag PCR analysis were performed to test MEF2A protein binding ability on MEF2A promoter in ov-MEF2A-flag transfected SMSCs; DNA marker: DL2000. (F) RNA level and protein level of MEF2A in si-circMEF2A1 and siRNA-NC transfected SMSCs, n = 3. (G) RNA level and protein level of MEF2A in ov-circMEF2A1 or ov-NC and miR-30a-3p mimic or mimic NC co-transfected SMSCs, n = 3. (H) RNA level and protein level of MEF2A in si-circMEF2A2 and siRNA-NC transfected SMSCs, n = 3. (I) RNA level and protein level of MEF2A in ov-circMEF2A2 or ov-NC and miR-148a-5p mimic or mimic NC co-transfected SMSCs, n = 3. (J) Dual-luciferase report analysis of MEF2A-WT and MEF2A-MT in DF-1 cells which co-transfected with miR-30a-3p mimic or mimic NC, n = 3. (K) Dual-luciferase report analysis of MEF2A-WT and MEF2A-MT in DF-1 cells which co-transfected with miR-148a-5p mimic or mimic NC, n = 3. (L) qRT-PCR analysis of myogenic genes in the cDNA samples generated from ov-circMEF2A1, ov-circMEF2A2, ov-NC, siRNA-NC, and si-MEF2A co-transfected SMSCs, n = 3. (M) Immunofluorescence of MyHC in ov-circMEF2A1, ov-circMEF2A2, ov-NC, siRNA-NC, and si-MEF2A co-transfected SMSCs. Scale bars: 200 μm. (N) The relative myotube area of ov-circMEF2A1, ov-circMEF2A2, ov-NC, siRNA-NC, and si-MEF2A co-transfected SMSCs was calculated by Image pro plus software, n = 9. (O) The proportion of MyHC+ cells of ov-circMEF2A1, ov-circMEF2A2, ov-NC, siRNA-NC, and si-MEF2A co-transfected SMSCs was calculated by Image pro plus software, n = 9. Data were displayed as mean ± SEM, independent sample t-test was used to analyze the statistical differences between each dataset, **P P < 0.05.</p

CircMEF2A2 targets and regulates miR-148a-5p.

(A) Venn analysis of human, mouse, and chicken circMEF2A2 targeted miRNAs which predicted by RNAhybrid software, three co-targeted miRNAs including miR-148a-5p, miR-34b-3p, and miR-34c-3p were observed. (B, C) qRT-PCR analysis of these three co-targeted miRNAs in the cDNA samples generated from si-circMEF2A2, siRNA-NC, ov-circMEF2A2, and ov-NC transfected SMSCs, n = 3. (D) RNA FISH analysis revealed the subcellular localization of circMEF2A2 and miR-148a-5p in normal growing SMSCs. Scale bars: 20 μm. (E) The image of circMEF2A2 and miR-148a-5p hybridization which was predicted by RNAhybrid software. (F) Partial sequence of circMEF2A2 containing wild-type (circMEF2A2-WT) and mutant-type (circMEF2A2-MT) of miR-148a-5p response element were subcloned into the dual-luciferase reporter vector. (G) Dual-luciferase report analysis of circMEF2A2-WT and circMEF2A2-MT in DF-1 cells which co-transfected with miR-148a-5p mimic or mimic NC, n = 3. (H, I) qRT-PCR analysis of miR-148a-5p in cDNA samples generated from miR-148a-5p inhibitor, inhibitor NC, miR-148a-5p mimic and mimic NC transfected SMSCs, n = 3. (J, K) qRT-PCR analysis of myogenic genes in the cDNA samples generated from miR-148a-5p inhibitor, inhibitor NC, miR-148a-5p mimic and mimic NC transfected SMSCs, n = 3. (L) Immunofluorescence of MyHC in miR-148a-5p inhibitor, inhibitor NC, miR-148a-5p mimic and mimic NC transfected SMSCs. Scale bars: 200 μm. (M, N) The relative myotube area of miR-148a-5p inhibitor, inhibitor NC, miR-148a-5p mimic, and mimic NC transfected SMSCs was calculated by Image pro plus software, n = 9. (O, P) The proportion of MyHC+ cells of miR-148a-5p inhibitor, inhibitor NC, miR-148a-5p mimic and mimic NC transfected SMSCs was calculated by Image pro plus software, n = 9. Data were displayed as mean ± SEM, independent sample t-test was used to analyze the statistical differences between each dataset, **P P < 0.05.</p

CircMEF2A1 promotes myogenesis in vitro and in vivo.

(A, B) qRT-PCR analysis of circMEF2A1 in the cDNA samples generated from circMEF2A1 siRNA (si-circMEF2A1), negative control siRNA (siRNA-NC), overexpression vector (ov-circMEF2A1), and negative control vector (ov-NC) transfected SMSCs, n = 3. (C, D) qRT-PCR analysis of myogenic genes including MyoD1, MyoG, MyF5, and MyHC in the cDNA samples generated from si-circMEF2A1, siRNA-NC, ov-circMEF2A1, and ov-NC transfected SMSCs, n = 3. (E) Immunofluorescence of MyHC in si-circMEF2A1, siRNA-NC, ov-circMEF2A1, and ov-NC transfected SMSCs. Scale bars: 200 μm. (F, G) The relative myotube area of si-circMEF2A1, siRNA-NC, ov-circMEF2A1, and ov-NC transfected SMSCs was calculated by Image pro plus software, n = 9. (H, I) The proportion of MyHC+ cells of si-circMEF2A1, siRNA-NC, ov-circMEF2A1, and ov-NC transfected SMSCs was calculated by Image pro plus software, n = 9. (J, K) qRT-PCR analysis of myogenic genes in the cDNA samples generated from lentivirus packaged circMEF2A1 shRNA (LV-si-circMEF2A1), negative control shRNA (LV-si-NC), overexpression vector (LV-ov-circMEF2A1), and negative control vector (LV-ov-NC) infected breast muscles of Tianfu chicks, n = 3. (L, M) The breast muscle rate of the LV-si-circMEF2A1, LV-si-NC, LV-ov-circMEF2A1, and LV-ov-NC infected Tianfu chicks, n = 6. (N, O) Representative photographs of the unilateral breast muscles of the LV-si-circMEF2A1, LV-si-NC, LV-ov-circMEF2A1, and LV-ov-NC infected Tianfu chicks. (P, Q) Hematoxylin and eosin (H&E) staining of the cross-section of LV-si-circMEF2A1, LV-si-NC, LV-ov-circMEF2A1, and LV-ov-NC infected chicks’ breast muscle. Scale bars: 200 μm. (R, S) The myofiber cross-sectional area of LV-si-circMEF2A1, LV-si-NC, LV-ov-circMEF2A1, and LV-ov-NC infected chicks’ breast muscles was calculated by Image J software, n = 9. Data were displayed as mean ± SEM, independent sample t-test was used to analyze the statistical differences between each dataset, **P P < 0.05.</p