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The well-conserved correlation between juvenility and tissue regeneration was first discussed by Charles Darwin. Ectopic Lin28 is known to play an important role in somatic reprogramming and tissue regeneration, but endogenous Lin28’s role in tissue homeostasis and juvenility had remained unclear. Through lineage tracing, we found that a rare subset of muscle stem cells (MuSCs) expressing Lin28a can respond to acute injury by proliferating as Pax3+ or Pax7+ MuSCs, and contribute to all types of myofibers during muscle regeneration. Compared with conventional Pax7+ MuSCs, Lin28a+ MuSCs express more Pax3 and show enhanced myogenicity in vitro. In terms of the epigenetic clock, adult Lin28a+ MuSCs lie between adult Pax7+ MuSCs and embryonic Pax7+ myoblasts according to their DNA methylation profiles. We found that Lin28a+ MuSCs upregulate several embryonic limb bud mesoderm transcription factors and could maintain a juvenile state with enhanced stem cell self-renewal and stress-responsiveness in vitro and in vivo. When combined with telomerase and TP53 inhibition to biomimic mouse Lin28a+ MuSCs, we found that Lin28a can rejuvenate and dedifferentiate aged human primary myoblasts into engraftable, self-renewing MuSCs. Mechanistic studies revealed that Lin28a activated the HIF1A pathway by optimizing mitochondrial ROS (mtROS), thereby rejuvenating MuSC self-renewal and muscle regeneration. Our findings connect the stem cell factor Lin28, mtROS metabolism and stress response pathways to the process of stem cell rejuvenation and tissue regeneration.

Plant height is an important agronomic trait for lodging resistance and yield. Here, we report a new plant-height-related gene, OsUBR7 in rice (Oryza sativa L.); knockout of OsUBR7 caused fewer cells in internodes, resulting in a semi-dwarf phenotype. OsUBR7 encodes a putative E3 ligase containing a plant homeodomain finger and a ubiquitin protein ligase E3 component N-recognin 7 (UBR7) domain. OsUBR7 interacts with histones and monoubiquitinates H2B (H2Bub1) at lysine148 in coordination with the E2 conjugase OsUBC18. OsUBR7 mediates H2Bub1 at a number of chromatin loci for the normal expression of target genes, including cell-cycle-related and pleiotropic genes, consistent with the observation that cell-cycle progression was suppressed in the osubr7 mutant owing to reductions in H2Bub1 and expression levels at these loci. The genetic divergence of OsUBR7 alleles among japonica and indica cultivars affects their transcriptional activity, and these alleles may have undergone selection during rice domestication. Overall, our results reveal a novel mechanism that mediates H2Bub1 in plants, and UBR7 orthologs could be utilized as an untapped epigenetic resource for crop improvement.

Isolable dialkylsilylene 5 reacts with dihydrogen in the presence of a small amount of a conventional Lewis acid (BPh3, BEt3) or a base (PPh3, PEt3, NPh3, NEt3) at low temperatures in a hydrocarbon solvent, giving the corresponding dihydrosilane 10 in high yields. Both 5/Lewis acid and Lewis base/5 pairs work as a frustrated Lewis pair (FLP) to split dihydrogen, being in accord with the amphoteric nature of silylene 5.

Hybrids between divergent populations commonly show hybrid sterility; this reproductive barrier hinders hybrid breeding of the japonica and indica rice (Oryza sativa L.) subspecies. Here we show that structural changes and copy number variation at the Sc locus confer japonica–indica hybrid male sterility. The japonica allele, Sc-j, contains a pollen-essential gene encoding a DUF1618-domain protein; the indica allele, Sc-i, contains two or three tandem-duplicated ~ 28-kb segments, each carrying an Sc-j-homolog with a distinct promoter. In Sc-j/Sc-i hybrids, the high-expression of Sc-i in sporophytic cells causes suppression of Sc-j expression in pollen and selective abortion of Sc-j-pollen, leading to transmission ratio distortion. Knocking out one or two of the three Sc-i copies by CRISPR/Cas9 rescues Sc-j expression and male fertility. Our results reveal the gene dosage-dependent allelic suppression as a mechanism of hybrid incompatibility, and provide an effective approach to overcome the reproductive barrier for hybrid breeding., A reproductive barrier between japonica and indica rice subspecies hinders hybrid breeding. Here, the authors reveal that structural and copy number variations of a pollen-essential gene, which encodes a DUF1618-domain protein, result in allelic suppression and subsequently cause hybrid male sterility.

An isolable dicoordinate dialkylsilylene, 2,2,5,5-tetrakis(trimethylsilyl)silacyclopentane-1,1-diyl (6), was found to react with CO2 and ArN═C═X (X = O, S) smoothly to give the corresponding bis(silyl)carbonate, 4-imino-1,3-dioxasiletane and 4-imino-1,3-dithiasiletane derivatives in high yields, respectively. The molecular structures of these products were determined by X-ray crystallography. All these reactions are parallel to those of a hypercoordinate silylene with η5-pentamethylcyclopentadienyl ligands, decamethylsilicocene, reported by Jutzi et al. and are suggested to involve similarly the formation of the corresponding Si═X doubly bonded compounds (X = O, S) at the initial steps. Mechanistic details of the multistep reaction of a model dialkylsilylene with CO2 were investigated using DFT calculations.

Activated carbons derived from corncob (CACs) were prepared by pyrolysis carbonization and KOH activation. Through modifying activation conditions, samples with large pore volume and ultrahigh BET specific surface area could be obtained. The sample achieved the highest hydrogen uptake capacity of 5.80 wt% at 40 bar and −196 °C. The as-obtained samples were characterized by N 2 -sorption, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Besides, thermogravimetric analysis was also employed to investigate the activation behavior of CACs. Detailed investigation on the activation parameters reveals that moderate activation temperature and heating rate are favorable for preparing CACs with high surface area, large pore volume and optimal pore size distribution. Meanwhile, the micropore volume between 0.65 nm and 0.85 nm along with BET surface area and total pore volume has great effects on hydrogen uptake capacities. The present results indicate that CACs are the most promising materials for hydrogen storage application.

The corncob-derived activated carbons (CACs) with ultrahigh surface area have been prepared by KOH activation. The as-obtained samples were characterized by N2-sorption, scanning electron microscopy (SEM), and high resolution transmission electron microscopy (HRTEM). The pore size distribution (PSD) was analyzed by using DFT method integrated slit-shaped pore model. An activated carbon sample (CAC4) shows BET surface area of 3708 m2 g−1 and pore volume of 2.0 cm3 g−1. The size effect of carbonized particle mixed with KOH was analyzed with the change of activation temperature. The results show the high activation temperature and smaller particle size are suitable to prepare activated carbons with high surface area and large pore volume, and the low activation temperature and bigger particle size are helpful to prepare activated carbons with smaller pore size and narrow pore size distribution. The hydrogen storage results show corncob-derived activated carbons have high hydrogen uptake capacity. The excess hydrogen uptake of sample CAC4 was 3.21 wt% at 1 bar and 77 K, and 5.80 wt% at about 40 bar and 77 K (the H2 uptake gets the highest at about 40 bar for CACs). The high-pressure hydrogen uptake at 298 K is different from the data at 77 K. The sample CAC3 shows the highest hydrogen uptake capacity of 1.05 wt% at 298 K and 164 bar, and higher than sample CAC4. This means that the changes of H2 uptake are related to textural characters materials caused by the preparation parameters as well as storage temperature and pressure.

Corncob-derived activated carbon (CAC) was prepared by potassium hydroxide activation. The Pt/Pd-doped CAC samples were prepared by two-step reduction method (ethylene glycol reduction plus hydrogen reduction). The as-obtained samples were characterized by N 2 -sorption, TEM and XRD. The results show the texture of CAC is varied after doping Pt/Pd. The Pd particles are easier to grow up than Pt particles on the surface of activated carbon. For containing Pt samples, the pore size distributions are different from original sample and Pd loaded sample. The hydrogen uptake results show excess hydrogen uptake capacity on the Pt/Pd-doped CAC samples are higher than pure CAC at 298 K, which should be attributed to hydrogen spillover effects. The 2.5%Pt and 2.5%Pd hybrid doped CAC sample shows the highest hydrogen uptake capacity (1.65 wt%) at 298 K and 180 bar, The particle size and distribution of Pt/Pd catalysts could play a crucial role on hydrogen uptake by spillover. The total hydrogen storage capacity analysis show that total H 2 storage capacities for all samples are similar, and spillover enhanced H 2 uptakes of metal-doped samples could not well support total H 2 storage capacity. The total pore volume of porous materials also is a key factor to affect total hydrogen storage capacity.

A series of super activated carbon have been prepared by potassium hydroxide activation of corncob. The as-obtained samples were characterized by SEM, TEM and N2-sorption. The results show morphologies and textural of activated carbon are highly depended on the activation temperature, heating rate, whereas the activation time is not a key factor. Morphologies and porous structure of activated carbons can be regulated by adjusting preparation parameters. A super activated carbon with BET surface area of 3530 m2/g and total pore volume of 1.94 cm3/g is obtained. However, the other activated carbon with smaller pore size exhibited the highest hydrogen uptake capacities exceeding 2.85 wt% at −196 °C and 1.0 bar, whose BET surface area is only 2988 m2/g. The correlation investigations show the micropore volume between 0.65 nm and 1.5 nm can be more important than BET surface area and total pore volume for hydrogen uptakes at −196 °C. The present results indicate that the corncob-derived activated carbons can be promising materials for hydrogen storage.

In recent years, CD133 has been identified as a cancer stem cell (CSC) marker in gliomas. Nevertheless, the clinical and prognostic value of CD133 in glioma patients remains controversial. Therefore, we conducted a systematic meta-analysis to evaluate the correlation of CD133 with World Health Organization (WHO) grade, age, gender, overall survival (OS), and progression-free survival (PFS) in glioma patients. Eligible studies on this subject were included, and then pooled odd ratios (ORs) and hazard ratios (HRs) with 95 % confidence intervals (95 % CIs) were estimated. Publication bias was assessed by the funnel plots, and heterogeneity and sensitivity were analyzed as well. In the present study, 21 articles with the total number of 1535 patients were included. High expression of CD133 in glioma patients was associated with high WHO grade (III + IV) (n = 11, OR 5.10, 95 % CI 2.99–8.69; p = 0.000), rather than age (n = 4, OR 2.54, 95 % CI 0.68–9.52; p = 0.167) and gender (n = 4, OR 0.71, 95 % CI 0.21–2.45; p = 0.587). In addition, survival analysis demonstrated a significant association between CD133 high expression and poor 2-year OS (n = 11, HR 2.18, 95 % CI 1.29–3.7; p = 0.004), 5-year OS (n = 4, HR 10.39, 95 % CI 2.59–41.63; p = 0.001), as well as PFS (n = 10, HR 2.34, 95 % CI 1.62–3.37; p = 0.000). Taken together, this study suggests that CD133 expression correlates to higher grade of gliomas and worse prognosis in glioma patients. Thus, CD133 could be recommended as a useful pathological and prognostic biomarker in clinical practice.

The reaction of silylene (I) with aromatic nitriles bearing electron-donating substituents on the phenyl ring (II) leads to the desired 1,4-diaza-2-siloles (III), whilst the reaction with aromatic nitriles with strong electron-withdrawing substituents (IV) affords 1,3-diaza-2-siloles (V).

The reactions of isolable dialkylsilylene 1 with aromatic acyl chlorides afforded aroylsilanes 3a–3c exclusively. Aroylsilanes 3a–3c were characterized by 1H-, 13C-, and 29Si-NMR spectroscopy, high-resolution mass spectrometry (HRMS), and single-crystal molecular structure analysis. The reaction mechanisms are discussed in comparison with related reaction of 1 with chloroalkanes and chlorosilanes.

The 1 : 2 reactions of isolable dialkylsilylene 1 with nitriles having electron-donating aromatic substituents gave 1,4-diaza-2-siloles with a hitherto-unknown type of ring system, in contrast to the previous studies showing exclusive formation of the corresponding 1,3-diaza-2-siloles; the reactions of 1 with aromatic nitriles bearing electron-withdrawing substituents afforded the latter ring system. The remarkable diversity of the reactions is explained by invoking the corresponding nitrile silaylides as key intermediates whose polarity switches depending on the substituents of nitriles.