Ecological risk assessment of dissolved heavy metals in the Yangtze River Estuary and Zhejiang coastal waters, China.

The study applied a tiered ecological risk assessment method to evaluate the long-term status and trend of the ecological risks of dissolved heavy metals from 2011 to 2019 in the Yangtze River Estuary and Zhejiang coastal waters, China. The results for spring, summer, and autumn of 2019 indicated that Pb, Cd, and Zn posed no adverse ecological risk, Cu posed a potential ecological risk, and As posed an ecological risk. The annual results from 2011 to 2019 suggested that Pb, Cd, and Zn posed no adverse ecological risks, and As and Cu posed an ecological risk.

Visible-Light Photocatalytic Highly Selective Oxidation of Alcohols into Carbonyl Compounds by CsPbBr Perovskite.

Conversion of alcohols into corresponding carbonyl compounds through an oxidation reaction with high conversion and selectivity simultaneously under mild conditions still remains a great challenge. Herein, a cost-effective and highly efficient photocatalytic protocol for selective oxidation of alcohols was developed using CsPbBr perovskite as a heterogeneous photocatalyst, which afforded aldehydes/ketones exclusively with a yield of 99% at ambient temperature under an air atmosphere. Moreover, the photocatalyst can be recycled at least 5 times without a significant decrease in catalytic activity.

Visible-Light-Driven [2 + 2] Photocycloaddition for Constructing Dimers of ,'-Diacyl-1,4-dihydropyrazines: Experimental and Theoretical Investigation.

In this study, the visible-light-driven [2 + 2] photocycloaddition of 1,4-dihydropyrazines in solution was reported. The ,-diacyl-1,4-dihydropyrazines with different substituents showed completely different reactivity under the irradiation of a 430 nm blue light-emitting diode (LED) lamp. ,'-Diacetyl-1,4-dihydropyrazine and ,'-dipropionyl-1,4-dihydropyrazine were the only compounds capable of undergoing a [2 + 2] photocycloaddition reaction, yielding syn-dimers and cage-dimers (known as 3,6,9,12-tetraazatetraasteranes) with overall yields of 76 and 83%, correspondingly.

Pd-catalyzed decarboxylative 1,4-addition reactions of benzofuran-based azadienes with allyl phenyl carbonates.

Under the catalysis of Pd(OAc)/dppf/NaCO, the decarboxylative 1,4-addition reaction of benzofuran-based azadienes with allyl phenyl carbonates took place easily and delivered the desired products in reasonable chemical yields. The chemical structure of the target compounds was clearly identified by single crystal X-ray structural analysis.

New di-spirocyclic labdane diterpenoids from the aerial parts of Leonurus japonicus.

Phytochemical investigation on the ethanol extract of a well-known medicinal herb Leonurus japonicus, led to the separation of 18 labdane type diterpenoids (1-18). Through comprehensive spectroscopic analyses and quantum chemical calculations, these compounds were structurally characterized as six new interesting 5,5,5-di-spirocyclic ones (1-6), two new (7 and 8) and six known (13-18) interesting 6,5,5-di-spirocyclic ones, a new rare 14,15-dinor derivative (9), and three new ones incorporating a γ-lactone unit (10-12). An in vitro neuroprotective assay in RSC96 cells revealed that compounds 7 and 12 exhibited neuroprotective activity in a concentration-dependent way, comparable to the reference drug N-acetylcysteine.

Pregnane steroid glycosides with multidrug resistance reversal activity from the stems of Marsdenia tenacissima.

Eighteen previously unreported pregnane glycosides, namely marsdenosides S1-S18, along with 15 known analogues, have been isolated from the stems of Marsdenia tenacissima. The structures of the undescribed compounds were elucidated by spectroscopic means, and their absolute configurations were established on the basis of time-dependent density functional theory (TD-DFT) based electronic circular dichroism (ECD) calculation, X-ray crystallography and acid hydrolysis. All the isolates were evaluated for their chemo-reversal ability against P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) in MCF-7/ADR cell line, and nine ones displayed moderate MDR reversal activity with reversal folds in the range of 2.

Chemoselective [2 + 2]/[3 + 2] Photocycloaddition of 1,4-Dihydropyridines: Experimental and Theoretical Investigation.

The photocycloaddition of 1,4-dihydropyridines (1,4-DHPs) is a main approach to synthesize structurally complex compounds, which are important intermediates for the preparation of cage compounds, such as 3,9-diazatetraasterane, 3,6-diazatetraasterane, 3,9-diazatetracyclododecane, and 6,12-diazaterakishomocubanes. The acquisition of different cage compounds depended on the chemoselectivity, which is mainly caused by the reaction conditions and structural characteristics of 1,4-DHPs. This study aimed to investigate the effect of the structural characteristics on chemoselectivity in [2 + 2]/[3 + 2] photocycloaddition of 1,4-DHPs.

Pregnane steroids and steroid glycosides with multidrug resistance reversal activity from Marsdenia tenacissima.

Twenty compounds comprising four pregnane steroids (2-4 & 20) and 16 pregnane glycosides (1 & 5-19) have been obtained from the ethanol extract of the roots of a Dai ethnological herb, Marsdenia tenacissima. Their structures were characterized on the basis of comprehensive spectroscopic analyses with 17 ones (1-17) being reported for the first time, including the rare cases (2 & 3) of free C steroids with 17α-acetyl substitution, compounds 4-7 bearing an unusual 14α-OH, and the first examples with simultaneous 14α-OH/17α-acetyl substitution (7) and glycosylation at C-12 position (10 & 11). An empirical rule for the identification of C-17 configuration, in C steroids incorporating the marsdenin constitution structure, was also proposed.

Distributed fiber mountain seismic monitoring and steady-state analysis under natural earthquakes.

Mountain dynamic response monitoring plays important roles in geological disaster evolution monitoring and warning. A distributed mountain seismic monitoring and steady-state analysis method is demonstrated with distributed acoustic sensing (DAS) and a natural earthquake stimulus. In the field test, the seismic detection capability is first verified by comparing the recorded seismic waveforms from DAS and existing seismic stations.

Steroid glycosides from the roots of Marsdenia tenacissima.

Eleven undescribed glycosylated C steroids and nine known homologous glycosides with diverse acyl substituents, as well as their common steroid aglycone, have been obtained from the roots of Marsdenia tenacissima. Their structures were elucidated mainly by comprehensive spectroscopic analyses and comparison with previously reported analogues, with the absolute configuration assignment being supported by chemical degradation, X-ray crystallography and ECD exciton chirality method. Among them, two pairs of regioisomers were found to exist as inseparable equilibrium mixtures due to an interesting intramolecular transesterification, and nicotinoyl substitution was first reported for metabolites from the title plant.

Development of pyrazolo[3,4-d]pyrimidin-4-one scaffold as novel CDK2 inhibitors: Design, synthesis, and biological evaluation.

A series of pyrazolo[3,4-d]pyrimidin-4-one scaffold were designed and synthesized as novel CDK2 inhibitors. By analyzing the common motifs of various known inhibitors, the designed compounds 1 were virtually screen for their inhibitory activity by docking into the active pocket of CDK2. The influence of different substitutes on the docking results was investigated.

Studies on chemoselective synthesis of 1,4- and 1,2-dihydropyridine derivatives by a Hantzsch-like reaction: a combined experimental and DFT study.

In the experimental process of preparing diethyl 3,5-dicarboxylate-1,4-dihydropyridine (1,4-DHP) by a Hantzsch-like reaction, it was found that a by-product named diethyl 3,5-dicarboxylate-1,2-dihydropyridine (1,2-DHP) was produced in the reaction. To discuss this phenomenon, the effects of the reaction conditions on the yield ratio of 1,4-DHP and 1,2-DHP were studied by using aromatic amines, aromatic aldehydes and ethyl propiolate as raw materials. The mechanisms for the formation of 1,4-DHP and 1,2-DHP were proposed based on the isolated intermediate named diethyl 4-((phenylamino)methylene)pent-2-enedioate generated by the Michael addition of aniline and ethyl propiolate.

Relationship between infertility-related stress and resilience with posttraumatic growth in infertile couples: gender differences and dyadic interaction.

Study Question: Are there any gender differences and dyadic interactions in the associations between infertility-related stress and resilience and posttraumatic growth in infertile couples?

Summary Answer: Husbands' posttraumatic growth was only impacted by their own infertility-related stress and resilience, whereas wives' posttraumatic growth was influenced by their own resilience and their spouses' resilience.

What Is Known Already: Posttraumatic growth may play a significant role in protecting the infertile couples' psychological well-being and contribute to positive pregnancy outcomes. The reciprocal influence on each other within the infertile couple in terms of relationships between infertility-related stress and resilience and posttraumatic growth has been largely overlooked.

Bioactive sesquiterpenoids from the flower buds of Tussilago farfara.

Eleven new compounds including five bisabolane (1-5) and three oplopane (6-8) sesquiterpenoids, a pair of benzopyran enantiomers (9 & 10) and a benzofuran derivative (11), along with six known sesquiterpenoid co-metabolites (12-17), have been obtained from the flower buds of Tussilago farfara. Their structures were elucidated by comprehensive spectroscopic analyses and comparison with structurally related known analogues. The absolute configurations of all the compounds except 11 were unequivocally assigned by various techniques, including Mosher's method and time-dependent density functional theory (TD-DFT) based calculations of C NMR and electronic circular dichroism (ECD) data.

Prenylated indole alkaloids and lignans from the flower buds of Tussilago farfara.

Six new compounds including four prenylated indole alkaloids (1-4) and two lignans (5-6), along with eight known cometabolites (7-14), were isolated from the flower buds of Tussilago farfara. Structures of the new compounds were elucidated by comparison with structurally related known analogues and also by comprehensive spectroscopic analyses. Their absolute configurations were determined by a variety of means including Mosher's method, Marfey's analysis, electronic circular dichroism (ECD) exciton chirality method and ECD calculations.

Design, Synthesis and Biological Evaluation of 4-Aryl-5,7-dihydro-6H-pyrrolo[2,3-d]pyrimidin-6-one Derivatives as a PI3Kα Inhibitor.

A novel series of 4-aryl-5,7-dihydro-6H-pyrrolo[2,3-d]pyrimidin-6-one derivatives were designed as a phosphoinositide 3-kinase α (PI3Kα) inhibitor by scaffold hopping. The target compounds, characterized by H-NMR, C-NMR and high resolution (HR)-MS, were synthesized from diethyl malonate and ethyl chloroacetate by nucleophilic substitution, ring-closure, chlorination and Suzuki reaction, etc. The biological activities were evaluated with cytotoxic activity in vitro on Uppsala 87 Malignant Glioma (U87MG) and prostate cancer-3 (PC-3) by Cell Counting Kit-8 (CCK-8).

New octadecanoid derivatives from the seeds of Ipomoea nil.

Four new octadecanoid derivatives (1-4) including a pair of enantiomers (1/2), along with 12 known analogues (5-16), were isolatedfrom the seeds of Ipomoea nil. Their structures were determined by detailed spectroscopic analyses and comparison with reported data of structurally related compounds, with the absolute configurations of 1 and 2 being assigned by an in situ dimolybdenum ECD method. Our bioassays revealed that these isolates did not show ABTS radical scavenging activity while 10 and 13 displayed better α-glucosidase inhibitory activity than the positive control acarbose (IC 167.

Chromane Enantiomers from the Flower Buds of Tussilago farfara L. and Assignments of Their Absolute Configurations.

Fourteen chromane derivatives of seven pairs of enantiomers (1-14) have been obtained from the ethanolic extract of the flower buds of Tussilago farfara L. Their structures with absolute configurations have been elucidated by detailed spectroscopic analyses, chemical methods, and particularly comparison of experimental ECD spectra with theoretically computed ones. Biological evaluations revealed that they did not show cytoprotective, antimicrobial, and α-glucosidase inhibitory activities.

Cytotoxic and antibacterial triterpenoids from the roots of Morinda officinalis var. officinalis.

Seven new pentacyclic triterpenoids including six ursane-type, marinoids A-F (1-6), and one oleanane-type, marinoid G (7), along with five known analogues (8-12), were separated from the roots of Morinda officinalis var. officinalis. Their structures were assigned by spectroscopic means especially analysis of 2D NMR data, with the absolute configurations of 1 and 2 being determined via comparison of their experimental ECD spectra with the computed ones.

Development of a loop-mediated isothermal amplification assay for the detection of chicken anemia virus.

Chicken anemia virus (CAV) infection has been reported in various poultry industries worldwide. Since CAV infection is becoming increasingly prevalent, especially in local chickens of China, rapid CAV detection has become essential. The conventional diagnostic methods are time consuming and need special expertise.

Formal [5+2] cycloaddition of vinylethylene carbonates to oxazol-5-(4H)-ones for the synthesis of 3,4-dihydrooxepin-2(7H)-ones.

Under the catalysis of Pd2(dba)3 (2.5 mol%), PPh3 (10.0 mol%) and TMSCl (1.

Diastereoselective and Enantioselective Synthesis of Barbiturate-Fused Spirotetrahydroquinolines via Chiral Palladium(0)/Ligand Complex Catalyzed [4 + 2] Cycloaddition of Vinyl Benzoxazinanones with Barbiturate-Based Olefins.

Under the catalysis of chiral palladium(0)/ligand complex, the [4 + 2] cycloaddition between vinyl benzoxazinanones and barbiturate-based olefins proceeded readily and provided barbiturate-fused spirotetrahydroquinolines in up to 96% chemical yield with up to >99:1 dr and 97% ee. The absolute configuration of barbiturate-fused spirotetrahydroquinolines was clearly identified by X-ray single crystal structure analysis. The reaction mechanism was proposed to shed light on the enantioselective formation of barbiturate-fused spirotetrahydroquinolines.

New Octadecanoid Enantiomers from the Whole Plants of .

In this study, 19 octadecanoid derivatives-four pairs of enantiomers (⁻), two racemic/scalemic mixtures (⁻), and nine biosynthetically related analogues-were obtained from the ethanolic extract of a Chinese medicinal plant, Willd. Their structures were elucidated on the basis of detailed spectroscopic analyses, with the absolute configurations of the new compounds assigned by time-dependent density functional theory (TD-DFT)-based electronic circular dichroism (ECD) calculations. Six of them (, ⁻ and ) were reported for the first time, while , and have been previously described as derivatives and are currently obtained as natural products.