Intracellular MicroRNA Imaging and Specific Discrimination of Prostate Cancer Circulating Tumor Cells Using Multifunctional Gold Nanoprobe-Based Thermophoretic Assay.

Circulating tumor cells (CTCs) have emerged as powerful biomarkers for diagnosis of prostate cancer. However, the effective identification and concurrently accurate imaging of CTCs for early screening of prostate cancer have been rarely explored. Herein, we reported a multifunctional gold nanoprobe-based thermophoretic assay for simultaneous specific distinguishing of prostate cancer CTCs and sensitive imaging of intracellular microRNA (miR-21), achieving the rapid and precise detection of prostate cancer. The multifunctional gold nanoprobe (GNP-DNA/Ab) was modified by two types of prostate-specific antibodies, anti-PSMA and anti-EpCAM, which could effectively recognize the targeting CTCs, and meanwhile linked double-stranded DNA for further visually imaging intracellular miR-21. Upon the specific internalization of GNP-DNA/Ab by PC-3 cells, target aberrant miR-21 could displace the signal strand to recover the fluorescence signal for sensitive detection at the single-cell level, achieving single PC-3 cell imaging benefiting from the thermophoresis-mediated signal amplification procedure. Taking advantage of the sensitive miR-21 imaging performance, GNP-DNA/Ab could be employed to discriminate the PC-3 and Jurkat cells because of the different expression levels of miR-21. Notably, PC-3 cells were efficiently recognized from white blood cells, exhibiting promising potential for the early diagnosis of prostate cancer. Furthermore, GNP-DNA/Ab possessed good biocompatibility and stability. Therefore, this work provides a great tool for aberrant miRNA-related detection and specific discrimination of CTCs, achieving the early and accurate diagnosis of prostate cancer.

Mechanism and Origins of Enantioselectivity in the Nickel-catalyzed Asymmetric Synthesis of Silicon-Stereogenic Benzosiloles.

As important π-skeletons, benzosiloles often possess unique electronic and optical properties and have been widely used in semiconductor materials. Therefore, great attention has been drawn to the area of developing novel synthetic methods for various benzosiloles. However, the synthesis of enantioenriched silicon-stereogenic benzosiloles is still at an early stage and remains to be explored. Herein, we performed systematic density functional theory studies on the recently reported nickel-catalyzed asymmetric synthesis of silicon-stereogenic benosiloles, which was enabled by an enantioselective desymmetrization of (2-alkenyl)aryl-substituted silacyclobutanes. Our computational study shows that the reaction mechanism involves ligand exchange, oxidative addition, alkene insertion, and hydrogen-transfer coupled reductive-demetalation steps. The proposed transmetalation and ß-hydride elimination mechanism was not found, which might be due to the unfavorable ring strain of the multicyclic intermediates. The novel hydrogen-transfer coupled reductive-demetalation mechanism was shown to be reasonable for the generation of the silicon-stereogenic benzosilole. Noncovalent interactions (including C-H···π and hydrogen bonding) in the rate-determining alkene insertion transition state account for the origins of the enantioselectivity. Our computational study sheds light on the detailed reaction mechanism and also provides insights for the development of novel approaches for synthesis of high-value silicon-stereogenic compounds.

A real-world study on the treatment of extremely preterm infants: a multi-center study in southwest area of Fujian Province in China.

BACKGROUND: Due to regional and cultural differences, the current status of extremely preterm infants(EPIs) treatment across different areas of mainland China remains unclear. This study investigated the survival rate and incidence of major diseases among EPIs in the southwest area of Fujian province. METHOD: This retrospective and multicenter study collected perinatal data from EPIs with gestational ages between 22-27+ 6w and born in the southwest area of Fujian province. The study population was divided into 6 groups based on gestational age at delivery. The primary outcome was the survival status at ordered hospital discharge or correct gestational age of 40 weeks, and the secondary outcome was the incidence of major diseases. The study analyzed the actual survival status of EPIs in the area. RESULT: A total of 2004 preterm infants with gestational ages of 22-27+ 6 weeks were enrolled in this study. Among them, 1535 cases (76.6%) were born in the delivery room but did not survive, 469 cases (23.4%) were transferred to the neonatal department for treatment, 101 cases (5.0%) received partial treatment, and 368 cases (18.4%) received complete treatment. The overall all-cause mortality rate was 84.4% (1691/2004). The survival rate and survival rate without major serious disease for EPIs who received complete treatment were 85.1% (313/368) and 31.5% (116/318), respectively. The survival rates for gestational ages 22-22+ 6w, 23-23+ 6w, 24-24+ 6w, 25-25+ 6w, 26-26+ 6w, and 27-27+ 6w were 0%, 0%, 59.1% (13/22), 83% (39/47), 88.8% (87/98), and 89.7% (174/198), respectively. The survival rates without major serious disease were 0%, 0%, 9.1% (2/22), 19.1% (9/47), 27.6% (27/98), and 40.2% (78/194), respectively. CONCLUSION: The all-cause mortality of EPIs in the southwest area of Fujian Province remains high, with a significant number of infants were given up after birth in the delivery room being the main influencing factor. The survival rate of EPIs who received complete treatment at 25-27 weeks in the NICU was similar to that in developed countries. However, the survival rate without major serious disease was significantly lower compared to high-income countries.

Aromatic 1,4,2,3-Diazadiborole Featuring an Unsymmetrical B=B Entity: A Versatile Synthon for Unusual Boron Heterocycles.

The replacement of a CC unit with an isoelectronic BN unit in aromatic systems can give rise to molecules and materials with fascinating properties. We report here the synthesis, characterization, and reactivity of a 1,4,2,3-diazadiborole species, 2, featuring an unprecedented 6π-aromatic BN-heterocyclic moiety that is isoelectronic to cyclopentadienide (Cp-). Bearing an unsymmetrical B=B entity, 2 exhibits reactivity toward oxidants, protic reagents, electrophiles, and unsaturated substrates. This reactivity facilitates the synthesis of a variety of novel mono- and bicyclic organoboron derivatives through mechanisms including ring retention, cleavage/recombination, annulation, and expansion. These findings reveal innovative synthetic routes to BN-embedded aromatic compounds via desymmetrization, affording unique building blocks for synthetic chemistry.

Enantioselective Nickel-Catalyzed Denitrogenative Transannulation En Route to N-N Atropisomers.

Nickel-catalyzed transannulation reactions triggered by the extrusion of small gaseous molecules have emerged as a powerful strategy for the efficient construction of heterocyclic compounds. However, their use in asymmetric synthesis remains challenging because of the difficulty in controlling stereo- and regioselectivity. Herein, we report the first nickel-catalyzed asymmetric synthesis of N-N atropisomers by the denitrogenative transannulation of benzotriazones with alkynes. A broad range of N-N atropisomers was obtained with excellent regio- and enantioselectivity under mild conditions. Moreover, density functional theory (DFT) calculations provided insights into the nickel-catalyzed reaction mechanism and enantioselectivity control.

Rhodium-Catalyzed Intramolecular Nitrogen Atom Insertion into Arene Rings.

In this study, we describe the direct insertion of an intramolecular nitrogen atom into an aromatic C-C bond. In this transformation, carbamoyl azides are activated by a Rh catalyst and subsequently directly inserted into the C-C bond of an arene ring to access fused azepine products. This transformation is challenging, owing to the existence of a competitive C-H amination pathway. The use of a paddlewheel dirhodium complex Rh2(esp)2 effectively inhibited the undesired C-H insertion. Density functional theory calculations were performed to reveal the reaction mechanism and origin of the chemoselectivity of the Rh-catalyzed reactions. The novel fused azepine products are highly robust and allow for downstream diversification.

Oriented Self-Assembly of Hierarchical Branch Organic Crystals for Asymmetric Photonics.

Organic hierarchical branch micro/nanostructures constituted by single crystals with inherent multichannel characteristics exhibit superior potential in regulating photon transmission for photonic circuits. However, organic branch micro/nanostructures with precise branch positions are extremely difficult to achieve due to the randomness of the nucleation process. Herein, by taking advantage of the dislocation stress field-impurity interaction that solute molecules deposit preferentially along the dislocation line, twinning deformation was introduced into microcrystals to induce oriented nucleation sites, and ultimately organic branch microstructures with controllable branch sites were fabricated. The growth mechanism of these controllable single crystals with an angle of 140° between trunk and branch is attributed to the low lattice mismatching ratio (η) of 4.8%. These as-prepared hierarchical branch single crystals with asymmetrical optical waveguide characteristics have been demonstrated as an optical logic gate with multiple input/out channels, which provides a route to command the nucleation sites and offers potential applications in the organic optoelectronics at the micro/nanoscale.

Reactivity and Selectivity of the Diels-Alder Reaction of Anthracene in [Pd6L4]12+ Supramolecular Cages: A Computational Study.

The field of supramolecular metal-organic cage catalysis has grown rapidly in recent years. However, theoretical studies regarding the reaction mechanism and reactivity and selectivity controlling factors for supramolecular catalysis are still underdeveloped. Herein, we demonstrate a detailed density functional theory study on the mechanism, catalytic efficiency, and regioselectivity of the Diels-Alder reaction in bulk solution and within two [Pd6L4]12+ supramolecular cages. Our calculations are consistent with experiments. The origins of the catalytic efficiency of the bowl-shaped cage 1 have been elucidated to be the host-guest stabilization of the transition states and the favorable entropy effect. The reasons for the switch of the regioselectivity from 9,10-addition to 1,4-addition within the octahedral cage 2 were attributed to the confinement effect and the noncovalent interactions. This work would shed light on the understanding of [Pd6L4]12+ metallocage-catalyzed reactions and provide a detailed mechanistic profile otherwise difficult to obtain from experiments. The findings of this study could also aid to the improvement and development of more efficient and selective supramolecular catalysis.

Catalytic Enantioselective Biltz Synthesis.

The Biltz synthesis establishes straightforward access to 5,5-disubstituted (thio)hydantoins by combining a 1,2-diketone and a (thio)urea. Its appealing features include inherent atom and step economy together with the potential to generate structurally diverse products. However, control of the stereochemistry of this reaction has proven to be a daunting challenge. Herein, we describe the first example of enantioselective catalytic Biltz synthesis which affords more than 40 thiohydantoins with high stereo- and regio-control, irrespective of the symmetry of thiourea structure. A one pot synthesis of corresponding hydantoins is also documented. Remarkably, experimental studies and DFT calculations establish the reaction pathway and origin of stereoselectivity.

Enantioselective Nickel-Catalyzed Hydrosilylation of 1,1-Disubstituted Allenes.

Here, we report the first example of Ni-catalyzed asymmetric hydrosilylation of 1,1-disubstituted allenes with high level of regioselectivities and enantioselectivities. The key to achieve this stereoselective hydrosilylation reaction was the development of the SPSiOL-derived bisphosphite ligands (SPSiPO). This protocol features broad substrate scope, excellent functional group, and heterocycle tolerance, thus provides a versatile method for the construction of enantioenriched tertiary allylsilanes in a straightforward and atom-economic manner. DFT calculations were performed to reveal the reaction mechanism and the origins of the enantioselectivity.

Utilizing Heterostructured Porous Particles to Improve Traditional Paper Chromatography for Spontaneous Protein Separation.

Chromatography is a classical technique for protein separation. However, the chromatography column is filled with tightly packed separation materials and requires an additional pressurizing pump to propel the flow of fluidic samples, largely restraining their applications. Here, we combine heterostructured porous particles with paper strips, realizing spontaneous separation of similarly sized proteins. The interconnected nanofibrous structure and good hydrophility of paper strips enable the spontaneous flow of the liquid sample, and the heterostructured porous particles provide versatile tools for protein separation via electrostatic interaction. The fabricated paper strips are inexpensive, user-friendly, and disposable and exhibit good separation performance. This work may offer a new avenue for fabricating on-site bioseparation tools and purifying various biomacromolecules.

Oxidation of Hypophosphorous Acid by a Ruthenium(VI) Nitrido Complex in Aqueous Acidic Solution. Evidence for a Proton-Coupled N-Atom Transfer Mechanism.

The oxidation of hypophosphorous acid (H3PO2) by a ruthenium(VI) nitrido complex, [(L)RuVI(N)(OH2)]+ (RuVIN; L = N,N'-bis(salicylidene)-o-cyclohexyldiamine dianion), has been studied in aqueous acidic solutions at pH 0-2.50. The reaction has the following stoichiometry: 2[(L)RuVI(N)(OH2)]+ + 3H3PO2 + H2O → 2[(L)RuIII(NH2P(OH)2)(OH2)]+ + H3PO3. The pseudo-first-order rate constant, kobs, depends linearly on [H3PO2], and the second-order rate constant k2 depends on [H+] according to the relationship k2 = k[H+]/([H+] + Ka), where k is the rate constant for the oxidation of H3PO2 molecule and Ka is the dissociation constant of H3PO2. At 298.0 K and I = 1.0 M, k = (2.04 ± 0.19) × 10-2 M-1 s-1 and Ka = (6.38 ± 0.63) × 10-2 M. A kinetic isotope effect (KIE) of 2.9 ± 0.1 was obtained when kinetic studies were carried out with D3PO2 at pH 1.16, suggesting P-H bond cleavage in the rate-determining step. On the other hand, when the kinetics were determined in D2O, an inverse KIE of 0.21 ± 0.03 (H3PO2 in H2O vs H3PO2 in D2O) was found. On the basis of experimental results and DFT calculations, the proposed mechanism involves an acid-catalyzed tautomerization of H2P(O)(OH) to HP(OH)2; the latter molecule is the reacting species which reacts with RuVIN via a proton-coupled N-atom transfer pathway.

Short-Term Nutritional Support Improves The Preoperative Nutritional Status of Infants With Non-Restrictive Ventricular Septal Defect: A Prospective Controlled Study.

OBJECTIVE: To investigate the effect of short-term nutritional support on improving preoperative nutritional status of infants with non-restrictive ventricular septal defect. METHODS: A prospective randomized controlled study was conducted from June 2021 to December 2021 at a provincial children's hospital in China. The difference of nutritional status between the intervention group and the control group after short-term nutritional support was compared. RESULTS: After one month of nutritional support, the weight, STRONGkids score, albumin, prealbumin, and hemoglobin in the intervention group significantly were higher than those in the control group (P < 0.05). The postoperative intensive care time and discharge time of the two groups significantly were lower in the intervention group than those in the control group (P < 0.05). CONCLUSION: The preoperative nutritional support of 1 month for infants with non-restrictive ventricular septal defect can effectively improve their preoperative nutritional status and promote postoperative recovery.

Biomineralization-inspired magnetic nanoflowers for sensitive miRNA detection based on exonuclease-assisted target recycling amplification.

Biomineralization-inspired magnetic hybrid nanoflowers were prepared facilely, and capture probes were easily immobilized on the obtained nanoflowers without tedious processing. Based on the magnetic hybrid nanoflowers and exonuclease-assisted target recycling amplification, a fluorescence miRNA sensor was fabricated. The presence of target miRNA leads to the formation of the double-strand structure, which would then be selectively digested by the exonuclease and increase fluorescence intensity. The target miRNA can be released for recycling and signal amplification. Under optimized reaction conditions, the hybrid nanoflower-based miRNA sensor had a broad detection range from 0.001 nM to 100 nM and a limit of detection of 0.23 pM (S/N = 3). The sensitive detection of miRNA in serum was also achieved with recoveries from 94.3% to 116.1%. This work provides a new insight into the fabrication of bioconjugated materials and shows great potential in miRNA sensing.

[Dynamic control of ERG20 expression to improve production of monoterpenes by engineering Saccharomyces cerevisiae].

Monoterpenes are widely used in cosmetics, food, medicine, agriculture and other fields. With the development of synthetic biology, it is considered as a potential way to create microbial cell factories to produce monoterpenes. Engineering Saccharomyces cerevisiae to produce monoterpenes has been a research hotspot in synthetic biology. In S. cerevisiae, the production of geranyl pyrophosphate(GPP) and farnesyl pyrophosphate(FPP) is catalyzed by a bifunctional enzyme farnesyl pyrophosphate synthetase(encoded by ERG20 gene) which is inclined to synthesize FPP essential for yeast growth. Therefore, reasonable control of FPP synthesis is the basis for efficient monoterpene synthesis in yeast cell factories. In order to achieve dynamic control from GPP to FPP biosynthesis in S. cerevisiae, we obtained a novel chassis strain HP001-pERG1-ERG20 by replacing the ERG20 promoter of the chassis strain HP001 with the promoter of cyclosqualene cyclase(ERG1) gene. Further, we reconstructed the metabolic pathway by using GPP and neryl diphosphate(NPP), cis-GPP as substrates in HP001-pERG1-ERG20. The yield of GPP-derived linalool increased by 42.5% to 7.6 mg·L~(-1), and that of NPP-derived nerol increased by 1 436.4% to 8.3 mg·L~(-1). This study provides a basis for the production of monoterpenes by microbial fermentation.

The Rational Design and Atroposelective Synthesis of Axially Chiral C2-Arylpyrrole-Derived Amino Alcohols.

Axially chiral biaryl diols have achieved great success in asymmetric catalysis. By contrast, axially chiral biaryl amino alcohols are far less developed. Herein, we have rationally designed a versatile C1 -symmetric biaryl amino alcohol scaffold 1-(1-amino-pyrrol-2-yl)naphthalen-2-ol (NPNOL) on the basis of axially chiral C2-arylpyrrole framework. For its enantioselective synthesis, the chiral phosphoric acid-catalyzed asymmetric Attanasi reaction between 1,3-dicarbonyl compounds and azoalkenes had been established. By using this practical method, a wide range of NPNOLs were readily prepared in high yields and excellent atroposelectivities (38 examples, up to 89 % yield and 99 % ee). DFT calculations were performed to reveal the reaction mechanism and the origins of the enantioselectivity. The easy transformations of NPNOL-derived products into organocatalysts/ligands and their preliminary applications in asymmetric catalytic reactions demonstrated the promising utility of NPNOL.

Sequential Norrish-Yang Cyclization and C-C Cleavage/Cross-Coupling of a [4.1.0] Fused Saturated Azacycle.

Methods that functionalize the periphery of azacylic scaffolds have garnered increasing interest in recent years. Herein, we investigate the selectivity of a solid-state Norrish-Yang cyclization (NYC) and subsequent C-C cleavage/cross-coupling reaction of a strained cyclopropane-fused azacyclic system. Surprisingly, the NYC primarily furnished a single lactam constitutional and diastereo-isomer. The regioselectivity of the C-C cleavage of the α-hydroxy-ß-lactam moiety could be varied by altering the ligand set used in the coupling chemistry. Experimental and computational observations are discussed.

Dendritic porous silica nanoparticles with high-curvature structures for a dual-mode DNA sensor based on fluorometer and person glucose meter.

A dual-mode DNA sensor was constructed to detect nucleic acid sensitively and selectively. Based on dendritic porous silica nanoparticles (DPSNs) and hybridization chain reaction (HCR) amplification strategy, the fabricated DNA sensor showed good sensitivity with low detection limits down to 2.18 pM and 4.02 pM by fluorescence (excited at 488 nm and emitted at 508 nm) and personal glucose meter (PGM) assays, respectively. This dual-mode detection of DNA offered superior reliability and accuracy and could meet the requirements of different testing environments, including laboratory confirmation and portable detection. Moreover, the impact of nanoparticles morphology on detection performance was also discussed. Due to the center-radial pores, DPSNs had high curvature morphology, which improved the coverage capacity, footprint, and deflection angle of probes. This work fabricated a dual-mode DNA sensor and revealed the relationship between morphology and detection performance, which brought new insights in novel biosensor development.

Reactivity and Selectivity Controlling Factors in the Pd/Dialkylbiarylphosphine-Catalyzed C-C Cleavage/Cross-Coupling of an N-Fused Bicyclo α-Hydroxy-ß-Lactam.

Density functional theory was employed in order to elucidate the mechanism and factors that lead to the observed regioselectivity in the dialkylbiarylphosphine (Phos)/Pd-catalyzed C-C cleavage/cross-coupling of an N-fused bicyclo α-hydroxy-ß-lactam, 1. We have identified that (a) a complex [(1)(Cs2CO3)]-PdL(PhBr) forms prior to a "base-mediated oxidative addition"; (b) Cs-carbonate (rather than a halide) deprotonates the alcohol substrate in the lowest energy pathway en route to Pd-alcoholate formation; (c) reactions using Phos ligands bearing OCF3 and OCF2H substituents on the "B"-ring are predicted to be selective toward proximal ring opening of 1; (d) steric repulsion between the bottom "B"-ring of the Phos ligand and the piperidine moiety of 1 controls the regioselectivity of the C-C cleavage followed by cross-coupling; and (e) the α- vs ß-selective functionalization of the piperidine moiety in 1 is influenced by the bulkiness of the R2-substituent of the coupling partner. These studies will aid in the design of selective functionalizations of the piperidine moiety in 1.

Mechanistic Study on Palladium-Catalyzed Regioselective Oxidative Amination: Roles of Ammonium Salts.

Anti-Markovnikov selective oxidative amination reaction with simple alkenes is particularly promising but challenging because of the inherent electronic effect of the alkene substrate which is in favor of the Markovnikov product. In a recently reported Pd-catalyzed anti-Markovnikov oxidative amination reaction, the addition of quaternary ammonium salts is shown to be critical. We performed a comprehensive DFT study to elucidate the reaction mechanism and the origin of the regioselectivity, as well as the roles of the ammonium salts. Our results show that without and with the ammonium salts the reaction mechanisms are different. Detailed analyses indicate that the steric effects account for the switch of regioselectivity. The roles of the quaternary ammonium salts have been elucidated: (1) Me4NOAc plays the role of base in deprotonating the phthalimide and allows the reaction to proceed through a trans-aminopalladation mechanism; (2) Me4NCl facilitates the thermodynamically favorable transformation of Pd(OAc)2 to the palladate ([Pd(AcO)2Cl2]2-), which lessens the polarity of the carbon-carbon double bond, minimizes the inherent electronic effects, and leads to a steric-effect-controlled reaction; (3) Me4NCl is essential in decreasing the activation barrier in the rate-determining ligand exchange step by Cl- acting as a better leaving group (compared to AcO-).