Selective Electrochemical Oxidation of Benzylic C-H to Benzylic Alcohols with the Aid of Imidazolium Radical Mediators.

Selective oxidation of benzylic C-H to benzylic alcohols is a well-known challenge in the chemical community since benzylic C-H is more prone to be overoxidized to benzylic ketones. In this work, we report the highly selective electro-oxidation of benzylic C-H to benzylic alcohols in an undivided cell in ionic liquid-based solution. As an example, the selectivity toward xanthydrol could be as high as 95.7% at complete conversion of xanthene, a typical benzylic C-H compound, on gram-scale in imidazolium bromide/H2O/DMF. Mechanism investigation reveals that the imidazolium radical generated in situ participants in a proton-coupled electron transfer process and low-barrier hydrogen bonds stabilize the reaction intermediates, together steering the redox equilibrium, favoring benzylic alcohols over benzylic ketones.

Structure and Ecological Function of Fungal Endophytes from Stems of Different Mulberry Cultivars.

To explore the microbial community structure and ecological function of mulberry and their potential relationship with the resistance of mulberry, the community structure and function of endophytic fungi in 18 mulberry cultivars were analyzed and predicted by using high-throughput sequencing technology and the FUNGuild database. A total of 352 operational taxonomic units of fungi were observed at a 97% similarity level, representing six phyla of fungi, Fungi_unclassified, Ascomycota, Basidiomycota, Zygomycota, Rozellomycota, and Chytridiomycota. Fungi_unclassified was dominant, and Ascomycota was relatively dominant in all cultivars. At the genus level, Ascomycota_unclassified was dominant, and Ampelomyces was relatively dominant, with a richness in TAIWANCHANGGUOSANG 16.47-8975.69 times that in the other cultivars. Classified Ascomycota_unclassified was 4.75-296.65 times more common in NANYUANSIJI than in the other cultivars. Based on the FUNGuild analysis method, we successfully annotated six nutrient types, namely, pathotroph, pathotroph-saprotroph, pathotroph-saprotroph-symbiotroph, saprotroph, saprotroph-symbiotroph, and symbiotroph, among which saprophytic-symbiotic accounted for the largest proportion and was absolutely dominant in TWC. This research suggests that community composition differs among cultivars and that the diversity and richness of endophytic fungi in resistant cultivars are higher than those in susceptible cultivars. The ecological functions of cultivars with different resistances are quite different.

Production of Piperidine and δ-Lactam Chemicals from Biomass-Derived Triacetic Acid Lactone.

Piperidine and δ-Lactam chemicals have wide application, which are currently produced from fossil resource in industry. Production of this kind of chemicals from lignocellulosic biomass is of great importance, but is challenging and the reported routes give low yield. Herein, we demonstrate the strategy to synthesize 2-methyl piperidine (MP) and 6-methylpiperidin-2-one (MPO) from biomass-derived triacetic acid lactone (TAL) that is produced microbially from glucose. In this route, TAL was firstly converted into 4-hydroxy-6-methylpyridin-2(1H)-one (HMPO) through facile aminolysis, subsequently HMPO was selectively transformed into MP or MPO over Ru catalysts supported on beta zeolite (Ru/BEA-X, X is the molar ratio of Si to Al) via the tandem reaction. It was found that the yield of MP could reach 76.5 % over Ru/BEA-60 in t-BuOH, and the yield of MPO could be 78.5 % in dioxane. Systematic studies reveal that the excellent catalytic performance of Ru/BEA-60 was closely correlated with the cooperative effects between active metal and acidic zeolite with large pore geometries. The related reaction pathway was studied on the basis of control experiments.

Src-mediated ligand release-independent EGFR transactivation involves TGF-ß-induced Smad3 activation in mesangial cells.

A great deal of evidence highlighted the pathophysiologic importance of TGF-ß1/Smad3 pathway in masangial extracellular matrix (ECM) accumulation, but some alternative signaling pathways are also involved. TGF-ß was shown recently to induce rapid and transient epidermal-like growth factor receptor (EGFR) transactivation and subsequent fibronectin expression via heparin-binding epidermal-like growth factors (HB-EGF) release and binding in mesangial cells, which is independent of Smad2 activation. However, whether TGF-ß could induce persistent EGFR transactivation remains to be identified. The present study demonstrates that in addition to transient EGFR transactivation, TGF-ß1 can also induce continuous EGFR transactivation by a non-ligand-dependent pathway in rat mesangial cells. This sustained EGFR transactivation is mainly due to Src kinase-mediated persistent EGFR tyrosine phosphorylation at Y845 rather than Y1173. TGF-ß1-induced early Smad3 phosphorylation is independent of transient EGFR transactivation and ERK1/2 activation initiated by HB-EGF release, whereas Src-mediated chronic EGFR transactivation and ERK1/2 activation participate in Smad3 activation in a relatively modest and delayed manner. Therefore, the present study further clarifies the mechanisms of EGFR transactivation in the TGF-ß-initiated ECM upregulation and raises the possibility that targeting EGFR may provide a viable alternative strategy for inhibiting TGF-ß in chronic kidney disease.

Parathyroid hormone inhibits TGF-ß/Smad signaling and extracellular matrix proteins upregulation in rat mesangial cells.

Accumulation of glomerular matrix is a hallmark of diabetic nephropathy. TGF-ß1 is a major cytokine mediating the production of various extracellular matrix (ECM) proteins. The aim of this study is to elucidate the effect of parathyroid hormone (PTH) on TGF-ß1 and high glucose-induced upregulation of ECM proteins in primary mesangial cells from Sprague-Dawley rat. The results showed that PTH pretreatment prevented TGF-ß1 and high glucose-induced Smad2/3 phosphorylation and consequent upregulation of fibronectin and type IV collagen within 4 h. The inhibitory effect of PTH is due to PTH1R activation, because knocking down PTH 1 receptor (PTH1R) by RNA interference reversed the inhibitory effect of PTH on TGF-ß1 and high glucose-induced Smad2/3 phosphorylation and ECM upregulation. Furthermore, it is found that PTH1R associated with TGF-ß type II receptor (TßR II) and both receptors internalized into the cytoplasm when mesangial cells were stimulated with PTH alone. The internalization of TßR II might reduce the amount of membrane TßR II, attenuate the sensitivity of mesangial cells to TGF-ß1, and therefore inhibit Smad activation and ECM upregulation induced by TGF-ß1 and high glucose. Further studies are needed to know whether the endocytic receptors are to be degraded or recycled, and evaluate the role of PTH in TGF-ß1 signaling more comprehensively.

A dual-mode turn-on fluorescent BODIPY-based probe for visualization of mercury ions in living cells.

A novel turn-on fluorescent 8-amino BODIPY-based probe carrying a thiourea unit as the mercury ion recognition unit has been developed. Due to the cascade reaction processes, consecutive color changes reflecting the electronic absorption and emission responses were observed upon addition of increased concentrations of mercury(ii) ions. The likely sensing mechanism was proposed as mercury ion-promoted cyclization and subsequent hydrolysis. The probe displayed a selective response to mercury ions over other metal ions. Additionally, experiments with living Human Hepatoma SMMC-7721 cells to visualize intracellular mercury ions in biological systems were carried out with the probe.

Highly selective and sensitive 1-amino BODIPY-based red fluorescent probe for thiophenols with high off-to-on contrast ratio.

A highly selective and sensitive turn-on red fluorescent 1-amino BODIPY-based probe (where BODIPY denotes indole-based boron-dipyrromethene) with high off-to-on contrast ratio has been developed. The probe displayed selective response to thiophenols over aliphatic thiols. Probe 1 is promising for the quantitative detection of thiophenol with a linear response from 6 × 10(-6) M to 1 × 10(-4) M, and the detection limit for thiophenol (PhSH) reaches 4 × 10(-6) M measured in acetonitrile/PBS buffer. The detection limit could be improved to 37 nM (detection limit to 4 ppb) in water when 1% Tween 20 was used to assist the dissolvation of probe 1 in water. Probe 1 is also a useful fluorescent probe for detecting thiophenols in living cells in red emission, which may greatly improve the detectable sensitivity.

Radical Cation Salt-Promoted Catalytic Aerobic sp(3) C-H Oxidation: Construction of Quinoline-Fused Lactones and Lactams.

A direct construction of quinoline-fused lactones and lactams was achieved by sp(3) C-H bond oxidation of N-aryl glycine esters and amides under catalytic radical cation salt-induced conditions. These polycyclic products are formed in a single step from readily accessible starting materials, and this method provides a new synthetic approach to this class of heterocycles.

Akt and RhoA activation in response to high glucose require caveolin-1 phosphorylation in mesangial cells.

Glomerular matrix accumulation is a hallmark of diabetic renal disease. Serine/threonine kinase PKC-ß1 mediates glucose-induced Akt S473 phosphorylation, RhoA activation, and transforming growth factor (TGF)-ß1 upregulation and finally leads to matrix upregulation in mesangial cells (MCs). It has been reported that glucose-induced PKC-ß1 activation is dependent on caveolin-1 and the presence of intact caveolae in MCs; however, whether activated PKC-ß1 regulates caveolin-1 expression and phosphorylation are unknown. Here, we showed that, although the caveolin-1 protein level had no significant change, the PKC-ß-specific inhibitor LY-333531 blocked caveolin-1 Y14 phosphorylation in high glucose (HG)-treated MCs and in the renal cortex of diabetic rats. The Src-specific inhibitor SU-6656 prevented the HG-induced association between PKC-ß1 and caveolin-1 and PKC-ß1 membrane translocation, whereas PKC-ß1 small interfering RNA failed to block Src activation, indicating that Src kinase is upstream of PKC-ß1 activation. Although LY-333531 blocked PKC-ß1 membrane translocation, it had no effect on the PKC-ß1/caveolin-1 association, suggesting that PKC-ß1 activation requires the interaction of caveolin-1 and PKC-ß1. PKC-ß1-mediated Akt S473 phosphorylation, RhoA activation, and fibronectin upregulation in response to HG were prevented by SU-6656 and nonphosphorylatable mutant caveolin-1 Y14A. In conclusion, Src activation by HG mediates the PKC-ß1/caveolin-1 association and PKC-ß1 activation, which assists in caveolin-1 Y14 phosphorylation by Src kinase. The downstream effects, including Akt S473 phosphorylation, RhoA activation, and fibronectin upregulation, require caveolin-1 Y14 phosphorylation. Caveolin-1 is thus an important mediator of the profibrogenic process in diabetic renal disease.

Catalytic sp3 C-H oxidation of peptides and their analogues by radical cation salts: from glycine amides to quinolines.

A catalytic α-sp(3) C-H oxidation of peptides and glycine amides was achieved under radical cation salt catalysis in the presence of O2, producing a series of substituted quinolines. The scope of this reaction shows good functional group tolerance and high efficiency of the oxidative functionalization.

Non-destructive prediction and visualization of anthocyanin content in mulberry fruits using hyperspectral imaging.

Being rich in anthocyanin is one of the most important physiological traits of mulberry fruits. Efficient and non-destructive detection of anthocyanin content and distribution in fruits is important for the breeding, cultivation, harvesting and selling of them. This study aims at building a fast, non-destructive, and high-precision method for detecting and visualizing anthocyanin content of mulberry fruit by using hyperspectral imaging. Visible near-infrared hyperspectral images of the fruits of two varieties at three maturity stages are collected. Successive projections algorithm (SPA), competitive adaptive reweighted sampling (CARS) and stacked auto-encoder (SAE) are used to reduce the dimension of high-dimensional hyperspectral data. The least squares-support vector machine and extreme learning machine (ELM) are used to build models for predicting the anthocyanin content of mulberry fruit. And genetic algorithm (GA) is used to optimize the major parameters of models. The results show that the higher the anthocyanin content is, the lower the spectral reflectance is. 15, 7 and 13 characteristic variables are extracted by applying CARS, SPA and SAE respectively. The model based on SAE-GA-ELM achieved the best performance with R2 of 0.97 and the RMSE of 0.22 mg/g in both the training set and testing set, and it is applied to retrieve the distribution of anthocyanin content in mulberry fruits. By applying SAE-GA-ELM model to each pixel of the mulberry fruit images, distribution maps are created to visualize the changes in anthocyanin content of mulberry fruits at three maturity stages. The overall results indicate that hyperspectral imaging, in combination with SAE-GA-ELM, can help achieve rapid, non-destructive and high-precision detection and visualization of anthocyanin content in mulberry fruits.

Non-destructive detection of protein content in mulberry leaves by using hyperspectral imaging.

Protein content is one of the most important indicators for assessing the quality of mulberry leaves. This work is carried out for the rapid and non-destructive detection of protein content of mulberry leaves using hyperspectral imaging (HSI) (Specim FX10 and FX17, Spectral Imaging Ltd., Oulu, Finland). The spectral range of the HSI acquisition system and data processing methods (pretreatment, feature extraction, and modeling) is compared. Hyperspectral images of three spectral ranges in 400-1,000 nm (Spectral Range I), 900-1,700 nm (Spectral Range II), and 400-1,700 nm (Spectral Range III) were considered. With standard normal variate (SNV), Savitzky-Golay first-order derivation, and multiplicative scatter correction used to preprocess the spectral data, and successive projections algorithm (SPA), competitive adaptive reweighted sampling, and random frog used to extract the characteristic wavelengths, regression models are constructed by using partial least square and least squares-support vector machine (LS-SVM). The protein content distribution of mulberry leaves is visualized based on the best model. The results show that the best results are obtained with the application of the model constructed by combining SNV with SPA and LS-SVM, showing an R 2 of up to 0.93, an RMSE of just 0.71 g/100 g, and an RPD of up to 3.83 based on the HSI acquisition system of 900-1700 nm. The protein content distribution map of mulberry leaves shows that the protein of healthy mulberry leaves distributes evenly among the mesophyll, with less protein content in the vein of the leaves. The above results show that rapid, non-destructive, and high-precision detection of protein content of mulberry leaves can be achieved by applying the SWIR HSI acquisition system combined with the SNV-SPA-LS-SVM algorithm.

Protocol for fabricating a photonic structure consisting of ZnO/Ag/ZnO film perforated with 2D periodic apertures based on photolithography technology.

A ZnO/Ag/ZnO film with 2D periodic apertures can have a high visible transmittance and low emittances in atmospheric windows for visible-infrared compatible camouflage and a high transmittance in 5-8 µm for heat dissipation by radiation. This following protocol details the fabrication process of such a photonic structure based on photolithography technology. Also described are the related challenges and troubleshooting steps. For complete details on the use and execution of this protocol, please refer to Dang and Ye (2021).

Regulator of calcineurin 1 deletion attenuates mitochondrial dysfunction and apoptosis in acute kidney injury through JNK/Mff signaling pathway.

Ischemia-reperfusion (I/R) induced acute kidney injury (AKI), characterized by excessive mitochondrial damage and cell apoptosis, remains a clinical challenge. Recent studies suggest that regulator of calcineurin 1 (RCAN1) regulates mitochondrial function in different cell types, but the underlying mechanisms require further investigation. Herein, we aim to explore whether RCAN1 involves in mitochondrial dysfunction in AKI and the exact mechanism. In present study, AKI was induced by I/R and cisplatin in RCAN1flox/flox mice and mice with renal tubular epithelial cells (TECs)-specific deletion of RCAN1. The role of RCAN1 in hypoxia-reoxygenation (HR) and cisplatin-induced injury in human renal proximal tubule epithelial cell line HK-2 was also examined by overexpression and knockdown of RCAN1. Mitochondrial function was assessed by transmission electron microscopy, JC-1 staining, MitoSOX staining, ATP production, mitochondrial fission and mitophagy. Apoptosis was detected by TUNEL assay, Annexin V-FITC staining and Western blotting analysis of apoptosis-related proteins. It was found that protein expression of RCAN1 was markedly upregulated in I/R- or cisplatin-induced AKI mouse models, as well as in HR models in HK-2 cells. RCAN1 deficiency significantly reduced kidney damage, mitochondrial dysfunction, and cell apoptosis, whereas RCAN1 overexpression led to the opposite phenotypes. Our in-depth mechanistic exploration demonstrated that RCAN1 increases the phosphorylation of mitochondrial fission factor (Mff) by binding to downstream c-Jun N-terminal kinase (JNK), then promotes dynamin related protein 1 (Drp1) migration to mitochondria, ultimately leads to excessive mitochondrial fission of renal TECs. In conclusion, our study suggests that RCAN1 could induce mitochondrial dysfunction and apoptosis by activating the downstream JNK/Mff signaling pathway. RCAN1 may be a potential therapeutic target for conferring protection against I/R- or cisplatin-AKI.

Design and characterization of oil-in-water nanoemulsion for enhanced oil recovery stabilized by amphiphilic copolymer, nonionic surfactant, and LAPONITE® RD.

The application of nanotechnology in the oil and gas industry has attracted widespread attention in recent years. This study aims to develop a nanoemulsion (NE) for use in enhanced oil recovery (EOR). The NE stabilized by anion amphiphilic copolymer, nonionic surfactant (Brij30) and modified LAPONITE® RD was prepared by the phase inversion composition (PIC) method. The appearance of the emulsion is translucent and the average particle size is less than 60 nm. The micromorphology and interfacial tension (IFT) are examined using transmission electron microscopy (TEM) and a spinning drop IFT meter, respectively. The NE possesses good stability evaluated by conductivity and particle size tests. The absolute value of the zeta potential of NE increases when modified LAPONITE® RD is added. In a core flooding experiment with an artificial sandstone core, the NE flooding increased oil recovery by 23.53% compared to water flooding.

Highly fluorescent carbon dots from coix seed for the determination of furazolidone and temperature.

In this work, blue emission fluorescent carbon dots (CDs) were fabricated by using the hydrothermal strategy from coix seed for the first time. We found that the prepared CDs possessed many excellent characteristics including excitation-dependent properties, good solubility and strong photostability. The optimal excitation and emission wavelength of CDs were 363 and 435 nm, respectively. Unbelievably, the fluorescence of CDs was selectively and effectively quenched with the addition of furazolidone (Fu). The quenching mechanisms might be assumed to the static quenching and inner filter effect (IFE). Based on this principle, a novel fluorescence probe was developed for the determination of Fu. At the same time, the proposed probe showed excellent sensitivity and selectivity towards Fu with a wide linear range from 0.5 to 100 µM, and the corresponding detection limit was 0.096 µM. Moreover, the CDs also could be applied for the sensing of temperature. The practical application of the CDs for Fu detection in real samples was also confirmed with the satisfactory recoveries changing from 96.6% to 108.5%, which provided huge possibility in the field of medical analysis.

Photoassisted Electron-Ion Synergic Doping Induced Phase Transition of n-VO2/p-GaN Thin-Film Heterojunction.

As a typical correlated metal oxide, vanadium dioxide (VO2) shows specific metal-insulator transition (MIT) properties and demonstrates great potential applications in ultrafast optoelectronic switch, resistive memory, and neuromorphic devices. Effective control of the MIT process is essential for improving the device performance. In the current study, we have first proposed a photoassisted ion-doping method to modulate the phase transition of the VO2 layer based on the photovoltaic effect and electron-ion synergic doping in acid solution. Experimental results show that, for the prepared n-VO2/p-GaN nanojunction, this photoassisted strategy can effectively dope the n-VO2 layer by H+, Al3+, or Mg2+ ions under light radiation and trigger consecutive insulator-metal-insulator transitions. If combined with standard lithography or electron beam etching processes, selective doping with nanoscale size area can also be achieved. This photoassisted doping method not only shows a facile route for MIT modulation via a doping route under ambient conditions but also supplies some clues for photosensitive detection in the future.

PKC-beta1 mediates glucose-induced Akt activation and TGF-beta1 upregulation in mesangial cells.

Accumulation of glomerular matrix is a hallmark of diabetic nephropathy. The serine/threonine kinase Akt mediates glucose-induced upregulation of collagen I in mesangial cells through transactivation of the EGF receptor (EGFR). In addition, in renal tubular cells, glucose-induced secretion of TGF-beta requires phosphoinositide-3-OH kinase, suggesting a possible role for Akt in the modulation of TGF-beta expression, but the mechanisms of Akt activation and its involvement in TGF-beta regulation are unknown. Here, in primary mesangial cells, high glucose induced AktS473 phosphorylation, which correlates with its activation, in a protein kinase C beta (PKC-beta)-dependent manner. Glucose led to PKC-beta1 membrane translocation and association with Akt, and PKC-beta1 immunoprecipitated from glucose-treated cells phosphorylated recombinant Akt on S473. PKC is known to mediate glucose-induced TGF-beta1 upregulation through the transcription factor AP-1; here, inhibitors of phosphoinositide-3-OH kinase, PKC-beta and Akt, and dominant-negative Akt all prevented glucose-induced activation of AP-1 and upregulation of TGF-beta1. Finally, pharmacologic and dominant negative inhibition of EGFR blocked glucose-induced activation of PKC-beta1, phosphorylation of AktS473, activation of AP-1, and upregulation of TGF-beta1. In vivo, the PKC-beta inhibitor ruboxistaurin prevented Akt activation in the renal cortex of diabetic rats. In conclusion, PKC-beta1 is an Akt S473 kinase in glucose-treated mesangial cells, and TGF-beta1 transcriptional upregulation requires EGFR/PKC-beta1/Akt signaling. New therapeutic approaches for diabetic nephropathy may result from targeting components of this pathway, particularly the initial EGFR transactivation.

Highly Efficient Synthesis of Amino Acids by Amination of Bio-Derived Hydroxy Acids with Ammonia over Ru Supported on N-Doped Carbon Nanotubes.

The amino acids have extensive applications, and their productions from biomass-derived feedstocks are very attractive. In this work, the synthesis of amino acids by amination of bio-derived hydroxy acids with ammonia over different metallic nano-catalysts supported on various supports is studied. It is found that Ru nano-catalysts on the nitrogen-doped carbon nanotubes (Ru/N-CNTs) have an outstanding performance for the reaction. Different hydroxy acids can be catalytically converted into the corresponding amino acids with yields up to 70.0 % under mild conditions, which is higher than those reported. The reasons for the high efficiency of the catalyst are investigated, and the reaction pathway is proposed on the basis of control experiments.

Transit From Autotrophism to Heterotrophism: Sequence Variation and Evolution of Chloroplast Genomes in Orobanchaceae Species.

The family Orobanchaceae including autotrophic, hemiparasitic, and holoparasitic species, is becoming a key taxa to study the evolution of chloroplast genomes in different lifestyles. But the early evolutionary trajectory in the transit from autotrophism to hemiparasitism still maintains unclear for the inadequate sampling. In this study, we compared 50 complete chloroplast genomes in Orobanchaceae, containing four newly sequenced plastomes from hemiparasitic Pedicularis, to elucidate the sequence variation patterns in the evolution of plastomes. Contrasted to the sequence and structural hypervariabilities in holoparasites, hemiparasitic plastomes exhibited high similarity to those of autotrophs in gene and GC contents. They are generally characterized with functional or physical loss of ndh/tRNA genes and the inverted small-single-copy region. Gene losses in Orobanchaceae were lineage-specific and convergent, possibly related to structural reconfiguration and expansion/contraction of the inverted region. Pseudogenization of ndh genes was unique in hemiparasites. At least in Pedicularis, the ndhF gene might be most sensitive to the environmental factors and easily pseudogenized when autotrophs transit to hemiparasites. And the changes in gene contents and structural variation potentially deeply rely on the feeding type. Selective pressure, together with mutational bias, was the dominant factor of shaping the codon usage patterns. The relaxed selective constraint, potentially with genome-based GC conversion (gBGC) and preferential codon usage, drive the fluctuation of GC contents among taxa with different lifestyles. Phylogenetic analysis in Orobanchaceae supported that parasitic species were single-originated while holoparasites were multiple-originated. Overall, the comparison of plastomes provided a good opportunity to understand the evolution process in Orobanchaceae with different lifestyles.