Configurationally Chiral SuFEx-Based Polymers.

Novel methods to make synthetic chiral polymers are highly desirable given their potential in a rapidly increasing number of bio-inspired applications. The enantiospecific sulfur-fluorine exchange (SuFEx) reaction of chiral di-sulfonimidoyl fluorides (di-SFs) with diphenols, was used to produce high-molecular-weight chiral polymers with configurational backbone chirality. The resulting new class of polymers, polysulfonimidates, can be efficiently produced via this step-growth mechanism for a wide range of di-SFs and diphenols, yielding MnPS up to 283 kDa with a typical dispersity D around 1.6. The optical activity of the resulting chiral polymers is largely due to the intrinsic asymmetry of the S atoms (configurational chirality). Finally, the enantiospecificity (ee>98 %) of the polymerization reaction was demonstrated by the degradation of a disulfide-containing polysulfonimidate. This novel route towards configurational main-chain chirality opens up new approaches towards tailor-made chiral polymers with precisely defined properties.

Sulfur-Phenolate Exchange: SuFEx-Derived Dynamic Covalent Reactions and Degradation of SuFEx Polymers.

The products of the SuFEx reaction between sulfonimidoyl fluorides and phenols, sulfonimidates, are shown to display dynamic covalent chemistry with other phenols. This reaction was shown to be enantiospecific, finished in minutes at room temperature in high yields, and useful for both asymmetric synthesis and sustainable polymer production. Its wide scope further extends the usefulness of SuFEx and related click chemistries.

Catalytic Enantioselective Synthesis and Switchable Chiroptical Property of Inherently Chiral Macrocycles.

We report herein a strategy to construct enantiopure inherently chiral macrocycles, ABCD-type heteracalix[4]aromatics, through a catalytic enantioselective intramolecular C-N bond forming reaction. A chiral ligand-palladium complex was found to efficiently induce the inherent chirality of molecules during the macrocyclization process with ee values up to >99%. The resulting ABCD-type heteracalix[4]aromatics displayed excellent and pH-triggered switchable electronic circular dichroism and circularly polarized luminescence properties.

Analyses of mRNA-seq and miRNA-seq of the brain reveal the sex differences of gene expression and regulation before and during gonadal differentiation in 17ß-estradiol or 17α-methyltestosterone-induced olive flounder (Paralichthys olivaceus).

Olive flounder (Paralichthys olivaceus) is a commercially important flatfish species cultured in East Asia. Female flounders generally grow more rapidly than males, therefore control of the sex ratio seems to be a proposed way to increase production. However, the sex determination gene and sex determination mechanism have yet been elucidated. The brain is an important organ that is involved in gonadal development. To explore the sex differences of gene expression in the brain before and during the flounder gonadal differentiation, we used messenger RNA (mRNA)-seq technology to investigate transcriptomes of male and female brains. Between female and male brains, 103 genes were differentially expressed before ovarian differentiation, 16 genes were differentially expressed before testicular differentiation, and 64 genes were differentially expressed during gonadal differentiation. According to annotation and Kyoto Encyclopedia of Genes and Genomes information, the differentially expressed genes (DEGs) were involved in circadian rhythm, circadian rhythm-fly, circadian entrainment, dopaminergic synapse, calcium signaling, glutamatergic synapse, taste transduction, herpes simplex infection, long-term depression, retrograde endocannabinoid signaling, and the synaptic vesicle cycle pathways. MicroRNA (miRNA)-seq was performed during the gonadal differentiation and the target genes of miRNAs were predicted. Integrated analysis of mRNA-seq and miRNA-seq showed that 29 of the 64 DEGs were regulated by the differentially expressed miRNAs during the gonadal differentiation. Our study provides a basis for further studies of brain sex differentiation and the molecular mechanism of sex determination in olive flounder.

Silicon-Free SuFEx Reactions of Sulfonimidoyl Fluorides: Scope, Enantioselectivity, and Mechanism.

SuFEx reactions, in which an S-F moiety reacts with a silyl-protected phenol, have been developed as powerful click reactions. In the current paper we open up the potential of SuFEx reactions as enantioselective reactions, analyze the role of Si and outline the mechanism of this reaction. As a result, fast, high-yielding, "Si-free" and enantiospecific SuFEx reactions of sulfonimidoyl fluorides have been developed, and their mechanism shown, by both experimental and theoretical methods, to yield chiral products.

The effects of novel heme oxygenase inhibitors on the growth of Pseudomonas aeruginosa.

OBJECTIVES: This study was aimed to develop small molecule inhibitors of the P. aeruginosa heme oxygenase (pa-HemO) as potential treatment of infections caused by P. aeruginosa. METHODS: New compounds were designed based on the crystal structure of pa-HemO. The binding affinities (KD) were determined using intrinsic fluorescence quenching assays. The anti-microbial effects of the new compounds was evaluated by minimal inhibitory concentration 50% (MIC50). RESULTS: Eleven compounds were synthesized as potential pa-HemO inhibitors. New compounds demonstrated KD values ranging from 1.5 to 180 µM, and MIC50 values ranging from 26 to 260 µg/mL. The compounds had good affinity with HemO and promising anti-microbial effects on P. aeruginosa. CONCLUSIONS: The new inhibitors described herein can inhibit the growth of P. aeruginosa via the inhibition of pa-HemO. There may be broad prospects for HemO inhibitors to treat P. aeruginosa related infections.

Roles of forkhead box protein L2 (foxl2) during gonad differentiation and maintenance in a fish, the olive flounder (Paralichthys olivaceus).

As an important maricultured fish, the olive flounder Paralichthys olivaceus shows sex-dimorphic growth. Thus, the molecular mechanisms involved in sex control in P. olivaceus have attracted researchers' attention. Among the sex-related genes, forkhead box protein L2 (foxl2) exhibits significant sex-dimorphic expression patterns and plays an important role in fish gonad differentiation and development. The present study first investigated the expression levels and promoter methylation dynamics of foxl2 during flounder gonad differentiation under treatments of high temperature and exogenous 17ß-oestradiol (E2). During high temperature treatment, the expression of flounder foxl2 may be repressed via maintenance of DNA methylation. Then, flounder with differentiated testis at Stages I-II were treated with exogenous 5ppm E2 or 5ppm E2+150ppm trilostane (TR) to investigate whether exogenous sex hormones could induce flounder sex reversal. The differentiated testis exhibited phenotypic variations of gonadal dysgenesis with upregulation of female-related genes (foxl2 and cytochrome P450 family 19 subfamily A (cyp19a)) and downregulation of male-related genes (cytochrome P450 family 11 subfamily B member 2 (cyp11b2), doublesex- and mab-3 related transcription factor 1 (dmrt1), anti-Mullerian hormone (amh) and SRY-box transcription factor 9 (sox9)). Furthermore, a cotransfection assay of the cells of the flounder Sertoli cell line indicated that Foxl2 was able alone or with nuclear receptor subfamily 5 group A member 2 (Nr5a2) jointly to upregulate expression of cyp19a. Moreover, Foxl2 and Nr5a2 repressed the expression of dmrt1. In summary, Foxl2 may play an important role in ovarian differentiation by maintaining cyp19a expression and antagonising the expression of dmrt1. However, upregulation of foxl2 is not sufficient to induce the sex reversal of differentiated testis.

Synthesis and Structure of Functionalized Homo Heteracalix[2]arene[2]triazines: Effect of All Heteroatom Bridges on Macrocyclic Conformation.

A number of unprecedented homo heteracalix[2]arene[2]triazines were synthesized by means of a fragment coupling approach. Two directional nucleophilic substitution reactions of N-Boc-protected 1,3-dihydrazobenzene with cyanuric acid chloride and 2-butoxy-4,6-dichloro-1,3,5-triazine led to hydrazo-linked trimers, which underwent an efficient macrocyclic condensation reaction with functionalized resorcinol derivatives to afford (NHNBoc)2,O2-calix[2]arene[2]triazine macrocycles, which contain a functional group either on the upper rim or the lower rim. The use of 1,3-phenylenediamines instead of resorcinol in the reaction produced (NR)2,(NHNBoc)2-calix[2]arene[2]triazines. Postmacrocyclization modifications such as a nucleophilic substitution reaction of chloro on triazine by amines and the removal of Boc from hydrazo moieties produced homo calix[2]arene[2]triazine derivatives. In the solid state, (NHNR)2,O2-bridged calix[2]arene[2]triazines with and without a substituent on the upper rim position and (NMe)2,(NHNBoc)2-calix[2]arene[2]triazine adopted a typical partial cone conformation while the heavily twisted 1,3-alternate conformational structures were observed for both (NHNBoc)2,O2-calix[2]arene[2]triazines bearing a functional group on the lower rim position and (NH)2,(NHNBoc)2-calix[2]arene[2]triazine. In solution, all synthesized homo heteracalix[2]arene[2]triazines existed as the mixture of different macrocyclic conformers, which underwent slow interconversions at room temperature relative to the NMR time scale.

Characteristics of Cyp11a during Gonad Differentiation of the Olive Flounder Paralichthys olivaceus.

The P450 side-chain cleavage enzyme, P450scc (Cyp11a) catalyzes the first enzymatic step for the synthesis of all steroid hormones in fish. To study its roles in gonads of the olive flounder Paralichthys olivaceus, an important maricultured fish species, we isolated the cyp11a genomic DNA sequence of 1396 bp, which consists of 5 exons and 4 introns. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) results indicated that the flounder cyp11a was exclusively expressed in gonad and head kidney tissues. Its expression level in the testis was higher than that in the ovary. According to the in situ hybridization patterns, cyp11a was mainly expressed in the Leydig cells of the testis, and the thecal cells of the ovary. Immunofluorescence analysis showed that Cyp11a was located in the cytoplasm of the cultured flounder testis cells. Further quantitative real-time PCR results presented the cyp11a differential expression patterns during gonad differentiation. Among different sampling points of the 17ß-estradiol (E2, 5 ppm) treatment group, cyp11a expression levels were relatively high in the differentiating ovary (30 and 40 mm total length, TL), and then significantly decreased in the differentiated ovary (80, 100 and 120 mm TL, p < 0.05). The pregnenolone level also dropped in the differentiated ovary. In the high temperature treatment group (HT group, 28 ± 0.5 °C), the cyp11a expression level fluctuated remarkably in the differentiating testis (60 mm TL), and then decreased in the differentiated testis (80, 100 mm TL, p < 0.05). In the testosterone (T, 5 ppm) treatment group, the cyp11a was expressed highly in undifferentiated gonads and the differentiating testis, and then dropped in the differentiated testis. Moreover, the levels of cholesterol and pregnenolone of the differentiating testis in the HT and T groups increased. The expression level of cyp11a was significantly down-regulated after the cultured flounder testis cells were treated with 75 and 150 µM cyclic adenosine monophosphate (cAMP), respectively (p < 0.05), and significantly up-regulated after treatment with 300 µM cAMP (p < 0.05). Both nuclear receptors NR5a2 and NR0b1 could significantly up-regulate the cyp11a gene expression in a dosage dependent way in the testis cells detected by cell transfection analysis (p < 0.05). The above data provides evidence that cyp11a would be involved in the flounder gonad differentiation and development.

Iodobenzene-Catalyzed Synthesis of Phenanthridinones via Oxidative C-H Amidation.

We report a novel synthesis of phenanthridinones from N-methoxybenzamides using an oxidative C-H amidation reaction at room temperature in open air with modest to excellent yields. This method demonstrated unprecedented substrate scope. In particular, it solved the long-standing challenge in the synthesis of phenanthridinones with sterically demanding substitutions.

One-pot sequential reaction to 2-substituted-phenanthridinones from N-methoxybenzamides.

The sequential use of a hypervalent iodine reagent leads to the one-pot synthesis of 2-bromo/chloro-phenanthridinones via an amidation of arenes followed by a regioselective halogenation reaction. These consecutive C-H functionalization reactions can be used efficiently to construct 2-substituted-phenanthridinones at room temperature with good to high yields. Application of the current method is highlighted by the concise synthesis of the natural product PJ34.

Significant association of cyp19a promoter methylation with environmental factors and gonadal differentiation in olive flounder Paralichthys olivaceus.

The sex ratio of olive flounder Paralichthys olivaceus is sensitive to temperature or exogenous hormone exposures in the period of gonadal differentiation. Among sex-related genes, cyp19a, encoding cytochrome P450 aromatase, exhibits significant sex-dimorphic expression pattern and plays an important role in fish gonadal differentiation and development. The present study investigated the expression levels and promoter methylation dynamics of cyp19a and its regulators (nr5a2 and nr0b1), and sex-steroid hormone levels during flounder gonadal differentiation under the treatments of high temperature and estradiol-17ß (E2). The results showed that levels of flounder cyp19a expression and estradiol-17ß were repressed by high temperature treatment during this period. The up-regulation of nr5a2 by E2 treatment may be related to the all-female formation, and up-regulation of nr0b1 by high temperature treatment may be associated with masculinization. Co-transfection assay indicated that nr5a2 and nr0b1 were antagonist regulators of cyp19a. Furthermore, cyp19a promoter exhibited significant demethylation phenomenon at early stage of ovarian differentiation. While, high temperature could repress the demethylation process, resulting in hypermethylation maintenance in cyp19a promoter. The hypermethylation promoter was able to suppress cyp19a expression by blocking the nr5a2-mediated transactivation activity in vitro. The DNA methylation of epigenetic modification in cyp19a promoter might be the vital way linking environmental factors and gonadal differentiation in flounder.

Long range detection of line-array multi-pulsed coding lidar by combining the Accumulation coherence and Subpixel-energy detection method.

This paper presents a multi-pulsed line-array push broom lidar, the pixel array scale reaches Geiger mode detectors in time-of-flight (TOF) depth imaging: by using time and space correlation between array elements of array avalanche photo detector (APD), light coding technology and a diode pumped solid-state laser with 10kHz repetition rate and 5µJ per pulses. Two signal enhancement methods, accumulation-coherence and high accuracy energy detection were combined improves the decode effect and realizes further long detection range. Experimental results and theory analysis indicating that the retrieval and denoising results of both simulated and real signals demonstrate that our method is practical and effective; what's more, the increasing scale of array sensor and the code bits can further improve system performance.

Quasi van der Waals Epitaxy of Single Crystalline GaN on Amorphous SiO2/Si(100) for Monolithic Optoelectronic Integration.

The realization of high quality (0001) GaN on Si(100) is paramount importance for the monolithic integration of Si-based integrated circuits and GaN-enabled optoelectronic devices. Nevertheless, thorny issues including large thermal mismatch and distinct crystal symmetries typically bring about uncontrollable polycrystalline GaN formation with considerable surface roughness on standard Si(100). Here a breakthrough of high-quality single-crystalline GaN film on polycrystalline SiO2/Si(100) is presented by quasi van der Waals epitaxy and fabricate the monolithically integrated photonic chips. The in-plane orientation of epilayer is aligned throughout a slip and rotation of high density AlN nuclei due to weak interfacial forces, while the out-of-plane orientation of GaN can be guided by multi-step growth on transfer-free graphene. For the first time, the monolithic integration of light-emitting diode (LED) and photodetector (PD) devices are accomplished on CMOS-compatible SiO2/Si(100). Remarkably, the self-powered PD affords a rapid response below 250 µs under adjacent LED radiation, demonstrating the responsivity and detectivity of 2.01 × 105 A/W and 4.64 × 1013 Jones, respectively. This work breaks a bottleneck of synthesizing large area single-crystal GaN on Si(100), which is anticipated to motivate the disruptive developments in Si-integrated optoelectronic devices.

[Local adenosine A1 receptors of baihui acupoint mediate cerebral ischemia tolerance induced by Electroacupuncture].

OBJECTIVE: To investigate whether local A1R of Baihui acupoint mediate cerebral ischemia tolerance induced by electro-acupuncture (EA). METHODS: Sixty SD rats were randomly divided into five groups, i.e., the sham-operation (S) group, the model group (M), the electroacupuncture (E) group, the CCPA group and the DMSO group. The focal cerebral ischemia/reperfusion model was established by middle cerebral artery occlusion (MCAO) in rats. Rats in the E group were received EA pretreatment baihui acupoint at 2 h before established MCAO. The rats in DMSO group and the CCPA group were injected with DMSO (20 µl) and CCPA (0.1 mmol/L) 20 µl into Baihui, respectively, at 2 h before established MCAO. After 24 h reperfusion, the rats' behavior, cerebral infarct volume, the cerebral Bcl-2 protein expression were assessed. RESULTS: Compared with M group, the rats' behavior was improved, the cerebral infarct volume was decreased and the Bcl-2 protein expression was up-regulated (P < 0.05) in the E group. Compared with M and DMSO group, the rats' behavior was improved, the cerebral infarct volume was decreased and the Bcl-2 protein expression was up-regulated (P < 0.05) in the CCPA group. There were no statistical differences between CCPA and E group. CONCLUSIONS: EA induced cerebral ischemia tolerance. Local A1R of Baihui acupoint possible mediate cerebral ischemia tolerance induced by Electroacupuncture.

Glycogen synthase kinase-3ß mediates toll-like receptors 4/nuclear factor kappa-B-activated cerebral ischemia-reperfusion injury through regulation of fat mass and obesity-associated protein.

BACKGROUND: Glycogen synthase kinase-3ß (GSK3ß), fat mass and obesity-associated protein (FTO), and toll-like receptors 4 (TLR4) take on critical significance in different biological processes, whereas their interactions remain unclear. The objective was the investigation of the interaction effect in cerebral ischemia-reperfusion (I/R) injury. METHODS: The function of the cerebral cortex in the mouse middle cerebral artery occlusion (MCAO) model (each group n = 6) and P12 cells oxygen-glucose deprivation/reoxygenation (OGD/R) model was analyzed using short hairpin GSK3ß lentivirus and overexpression of FTO lentivirus (in vitro), TLR4 inhibitor (TAK242), and LiCl to regulate GSK3ß, FTO, TLR4 expression, and GSK3ß activity, respectively. RESULTS: After GSK3ß knockdown in the OGD/R model of PC12 cells, the levels of TLR4 and p-p65 were lower than in the control, and the level of FTO was higher than in the control. Knockdown GSK3ß reversed the OGD/R-induced nuclear factor kappa-B transfer to the intranuclear nuclei. As indicated by the result, TLR4 expression was down-regulated by overexpressed FTO, and TLR4 expression was up-regulated notably after inhibition of FTO with the use of R-2HG. After the inhibition of the activity of GSK3ß in vivo, the reduction of FTO in mice suffering from MCAO was reversed. CONCLUSIONS: Our research shows that GSK3ß/FTO/TLR4 pathway contributes to cerebral I/R injury.

Enantiospecific Synthesis of Aniline-Derived Sulfonimidamides.

Reaction of sulfonimidoyl fluorides with anilines and Ca(NTf2)2 results in the formation of chiral sulfonimidamides. The reaction proceeds with inversion of the stereocenter at a sulfur atom. Enantiospecificity of the reaction was observed for all studied non-heterocyclic anilines. Combined experimental and computational mechanistic studies highlight chelate-type coordination of the sulfonimidoyl group to Ca(NTf2)2 and the formation of a SN2-like transition state, in which leaving F- coordinates with the Ca2+ ion.

Efficient Strategy for Radiative Cooling Based on Ultra-Broad-Band Infrared Regulation of Flexible Bilayer Film.

Flexible thermal radiation films with adjustable broad-band infrared radiation could maintain various heat-generating electronic devices working stably in corresponding operating temperatures, making them good candidates for radiative cooling (RC) material. However, the controllable radiation peaks of the metamaterial were narrow, and manipulation was a time-consuming and complex process. Herein, we design a simple TiN/Si bilayer film with controllable broad-band radiation peaks at a thermal radiation wavelength of 3.5-20 µm by impedance matching. Meanwhile, the different bilayer films applied to aluminum devices at different temperatures exhibit outstanding heat dissipation efficiency and maintain the corresponding equilibrium temperature to ensure that devices work stably for a long time. Moreover, the bilayer films deposited on the flexible PI substrates exhibit preferable thermostability and higher tensile strength than existing radiative cooling materials deposited on PDMS, PE, PMMA or TPX, etc. This work provides an effective strategy to realize efficient radiation cooling for flexible electronic devices and spacecraft appendages.

A live-cell image-based machine learning strategy for reducing variability in PSC differentiation systems.

The differentiation of pluripotent stem cells (PSCs) into diverse functional cell types provides a promising solution to support drug discovery, disease modeling, and regenerative medicine. However, functional cell differentiation is currently limited by the substantial line-to-line and batch-to-batch variabilities, which severely impede the progress of scientific research and the manufacturing of cell products. For instance, PSC-to-cardiomyocyte (CM) differentiation is vulnerable to inappropriate doses of CHIR99021 (CHIR) that are applied in the initial stage of mesoderm differentiation. Here, by harnessing live-cell bright-field imaging and machine learning (ML), we realize real-time cell recognition in the entire differentiation process, e.g., CMs, cardiac progenitor cells (CPCs), PSC clones, and even misdifferentiated cells. This enables non-invasive prediction of differentiation efficiency, purification of ML-recognized CMs and CPCs for reducing cell contamination, early assessment of the CHIR dose for correcting the misdifferentiation trajectory, and evaluation of initial PSC colonies for controlling the start point of differentiation, all of which provide a more invulnerable differentiation method with resistance to variability. Moreover, with the established ML models as a readout for the chemical screen, we identify a CDK8 inhibitor that can further improve the cell resistance to the overdose of CHIR. Together, this study indicates that artificial intelligence is able to guide and iteratively optimize PSC differentiation to achieve consistently high efficiency across cell lines and batches, providing a better understanding and rational modulation of the differentiation process for functional cell manufacturing in biomedical applications.