Search

Resource partitioning through temporal, spatial and/or trophic dimensions is suggested as a mechanism for long‐term coexistence among sympatric species. However, how the combined effects of the different dimensions contribute to the partitioning during the ontogenetic process is unclear.We sampled two sympatric icefish species [Protosalanx hyalocranius (Abbott, 1901) and Neosalanx taihuensis (Chen, 1956)] monthly from July 2015 to June 2016 in Hongze Lake, China. We evaluated the hypothesis that combined effects of separation in gonad development dynamics and ontogenetic diet shifts facilitate resource partitioning in temporal and trophic dimensions during the entire life cycle process of the two icefish species.Increased gonadosomatic index (GSI) of female P. hyalocranius occurred during October 2015 to January 2016, and that of female N. taihuensis occurred during January to March 2016. Thus, energy and nutrition investments in gonad development separated seasonally between the two species. Consequently, temporal separations in gonad development between P. hyalocranius (GSI peaked in January) and N. taihuensis (GSI peaked in March) indicated potential segregations in spawning time and consequent larval abundance peaks, suggesting reduced overlap of prey consumption during the early life stages.The dominant diet of P. hyalocranius shifted from cladocerans to copepods, and then shrimp, and finally to fish during its ontogeny, whereas the dominant diet of N. taihuensis changed gradually from cladocerans to copepods during its ontogeny. The diet overlap in cladocerans during May was high between the two species.Our findings support the hypothesis of an associative strategy, combining temporal (separations in gonad development and subsequently spawning time) and trophic (ontogenetic diet shifts) dimensions, for the resource partitioning between P. hyalocranius and N. taihuensis, which may be an important mechanism for long‐term coexistence among sympatric short‐lived fishes. [ABSTRACT FROM AUTHOR]

The development of high activity, low-cost and stability hydrogen evolution reaction (HER) catalysts is a core issue in the field of water splitting. Herein, the bimetallic CoMo MOFs-derived N-doped carbon nanospheres with Co/Mo–N bonds is proposed to effectively improve the electrocatalytic HER performance. Meanwhile, the combination of the porous and spherical structure further promotes the effective contact on the electrode/electrolyte interface while enhancing the electrolyte into the inner structure of the material for a fast HER process. In addition, the N-doped and bimetallic Co/Mo oxides on the rough surface of nanospheres have the capability to furnish more electrocatalytic active sites. The obtained electrocatalyst owns the small overpotential of 112 mV at 10 mA cm−2 and Tafel slope of 106.8 mV dec−1 in 1.0 M KOH solution. This work provides a new prospect for the rational design and fabrication of bimetallic active sites in carbon nanomaterials electrocatalysts in the relevant energy applications. [Display omitted] • Bimetallic CoMo MOFs-derived N-doped carbon nanospheres is proposed to effectively improve the electrocatalytic HER performance. • The formation of Co–N and Mo–N, which would provide a fast electron transfer path in electrocatalytic process. • The formation of CoO and CoMoO 3 species could synergistic promote the adsorption and reaction of the H ads intermediates. [ABSTRACT FROM AUTHOR]

To analyze the psychological experience characteristics of nursing staff with different roles in response to sudden public health emergencies so as to formulate targeted intervention strategies against the negative psychology of nursing staff. Methods Based on the principle of information saturation, purposive sampling was used to select nursing staff with different roles, and semi-structured interviews were conducted from July to August 2022. The interview data were sorted and analyzed by QSR Nvivo 11.0 software. Results A total of 18 nursing staff members were included in this interview, including 9 managers and 9 non-managers. Four tree nodes were determined based on the interview materials: positive orientation of work feelings, negative experience in the support process, influencing factors of negative experience, and psychological adjustment measures. The high-frequency words were "problem", "work", "influence", "psychology", "pressure", "communication", etc. The most important sub-node in the tree node of "influencing factors of negative experience", "psychological adjustment measures", "positive orientation of work feelings" and "negative experience in the support process" was "management pressure", "self-release path", "sense of value" and "worry", respectively. The proportion of negative matrix coding words for nursing management personnel was much greater than that for non-management personnel, while the proportion of positive matrix coding words was much smaller than that for non-management personnel. Conclusions There were different degrees of negative psychological tendencies among front -line emergency nurses in sudden public health emergencies, among which management personnel were more prominent. Corresponding psychological adjustment intervention strategies should be formulated for nursing managers in emergency work. [ABSTRACT FROM AUTHOR]

Marine cyclic peptides have become an important source for drug development. In this work, two novel cyclic peptide zygosporamide analogs with the isoindolinone fragment were prepared, which have broad-spectrum antitumor activity. We have tried to compare their bioactivities by changing the amino acid (R-3Leu and S-4Leu) configuration. Notably, compound 8, with R-3Leu and S-4Leu residues, showed better inhibiting ability than that of compound 9, which contains S-3Leu and R-4Leu residues. Furthermore, careful molecular docking indicated that compound 8 presented stronger binding with the EGFR protein of liver cancer cells, providing an explanation for the difference in bioactivity. This research has provided a useful guide for peptide-based drug-target design. [ABSTRACT FROM AUTHOR]

Fabrication of highly efficient and earth-abundant bifunctional electrocatalyst to accelerate the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are critical for overall water splitting. In this work, bimetallic Co/Mo oxides modified reduced graphene oxide (rGO) was synthesized using a simple one-pot hydrothermal method, which significantly improved the electrocatalytic activity in both HER and OER. Under the optimal conditions, the double layer capacitance of rGO modified by Co/Mo bimetal is 78.08 mF cm−2. The overpotential required for HER to reach -10 mA cm−2 current density is 488 mV, the dynamic Tafel slope is 126 mV dec−1. The overpotential required for OER to reach 10 mA cm−2 current density is 420 mV, the slope of kinetic Tafel is 169 mV dec−1. This work provides a new prospect for the rational design and fabrication of efficient HER/OER bifunctional electrocatalysts in electrochemical energy device application.Graphical Abstract: Fabrication of highly efficient and earth-abundant bifunctional electrocatalyst to accelerate the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are critical for overall water splitting. In this work, bimetallic Co/Mo oxides modified reduced graphene oxide (rGO) was synthesized using a simple one-pot hydrothermal method, which significantly improved the electrocatalytic activity in both HER and OER. Under the optimal conditions, the double layer capacitance of rGO modified by Co/Mo bimetal is 78.08 mF cm−2. The overpotential required for HER to reach -10 mA cm−2 current density is 488 mV, the dynamic Tafel slope is 126 mV dec−1. The overpotential required for OER to reach 10 mA cm−2 current density is 420 mV, the slope of kinetic Tafel is 169 mV dec−1. This work provides a new prospect for the rational design and fabrication of efficient HER/OER bifunctional electrocatalysts in electrochemical energy device application. [ABSTRACT FROM AUTHOR]

A facile methodology for the synthesis of bicyclopeptides containing isoindolone was developed by an intramolecularly photo-induced electron transfer cyclo-reaction (IPETC) with high yield and stereoselectivity. Nine bisulfide-bridged bisisodindolone–cyclopeptides were successfully prepared based on the construction of an intramolecular bis-(donor–acceptor) electron system using L -cystine as the linker. The stereostructures of the bicyclopeptides were determined by ECD and 13C-NMR spectra combined with quantum chemistry calculations. The research provided a possible solution for the preparation of multi-cyclopeptides with complex and rigid cyclic structures by introducing cysteine moieties into linear peptides. [ABSTRACT FROM AUTHOR]

Two novel isoindole-doped cyclopeptide analogs of phakellistatin 2 with γ-turns were prepared. The compound with all D -Pro residues showed better antitumor activity against HepG-2 cells than that containing all L -Pro moieties, indicating the importance of the handedness of the conformation. LDH release tests showed that the compounds killed the cancer cells through a membrane disruption mechanism. [ABSTRACT FROM AUTHOR]

Two novel chiral cyclic peptide analogues of galaxamide were synthesized by photoinduced single electron transfer cyclization. Their stereochemistry was studied by experimental and theoretical ECD simulations. The title compounds were found to be active against HepG-2 cell lines (IC50 = 19.52 for 1 and 26.34 μg mL−1 for 2). [ABSTRACT FROM AUTHOR]

• A facile co-precipitation method can be used to prepare graphitic-based composite photocatalyst. • The Co and Fe doping structures could enhance the separation efficiency and transfer of photogenerated carriers. • The coupling structure could enhance the chemical stability and photocatalytic activity. The photocatalyst Lys-FeCoLDH@g-C 3 N 4 nanohybrids were synthesized successfully by a facile in situ co-precipitation method. It is found that the layered nanosheet degradation efficiency of Rhodamine B reached 98.07% in 90 min under visible light irradiation by photocatalysis. In addition, photo-electrochemical measurements demonstrated that the structure of 5 %Lys-CoFe-LDH@g-C 3 N 4 could enhance the separation efficiency and transfer of photogenerated carriers. This study provides a new idea for the development of novel photocatalysts for the high-efficiency and active degradation of wastewater. [ABSTRACT FROM AUTHOR]

Photoinduced single electron transfer cyclization processes for synthesis of a series of 3‐hydroxy isoindolinone cyclotripeptides containing double pharmacophores (cyclotripeptides and phthalimide moiety) are described to develop novel antitumor cyclopeptide drugs. The results showed that our proposed method could be used to synthesize various isoindolinone cyclotripeptides highly regioselectively at a moderate rate. Moreover, the inhibitory potency toward human cervical carcinoma HeLa cells of the target cyclopeptides and the linear tripeptide precursors were evaluated, and most of the compounds were observed with potent inhibition ability against tumor growth. Specifically, compound 6c was found to inhibit HeLa cells with an IC50 value of 32 μM, which may serve as a potential candidate for drug development. In addition, 3‐hydroxy isoindolinone‐cyclo‐Gly‐Ala‐Pro (6a1) was chosen from the obtained cyclopeptides for the absolute configuration research, and an S configuration of C‐3 was established by experimental electronic circular dichroism with the aid of theoretical calculations. [ABSTRACT FROM AUTHOR]

Two novel Fenestin A analogs (1 and 2) containing a phthalimide moiety are prepared by photoinduced cyclization. Their absolute configurations were determined by experimental ECD with the aid of theoretical calculations. The resulting compounds are active in HeLa (IC50 = 28.2 μM for 1 and 36.5 μM for 2) and HepG-2 cell lines (IC50 = 33.5 μM for 1 and 40.3 μM for 2). [ABSTRACT FROM AUTHOR]

• A facile methodology for novel cyclopeptide p53-MDM2 inhibitors with isoindo-linone synthesis has been developed based on photo-induced single electron transfer reaction (SET). • The effect of compound 1 on mitochondrial membrane potential and intracellular Ca2+ concentration have been studied extensively to evaluate the antitumor potential. • The molecular docking suggested that compound 1 presented stronger binding with MDM2 oncoprotein of liver cancer cells, and indicating that compound 1 is a potential inhibitor of MDM2 interactions. In this paper, two kinds of novel p53 cyclopeptides containing 1-Phe, 2-Trp, 3-Leu, 4-Leu/Pro residues and isoindolinone were synthesized by intramolecular photoinduced single electron transfer cyclization reactions, and their structures were confirmed by 1H NMR, 13C NMR and HR-MS. Comparison of bioactivity of compound 1 and 2 against HeLa, HepG-2, MDA-MB, MCF-7 and 4T1 cell lines by MTT assay, indicated moderate antiproliferative activity of compound 2 (4-Pro). Moreover, compound 1 (4-Leu) with isoindolinone fragments exhibited the strongest antiproliferative activity against HepG-2 cell line with an IC 50 of 9.54 μg/mL. The effect of compound 1 on mitochondrial membrane potential and intracellular Ca2+ concentration have been studied to evaluate the antitumor potential. The decrease of mitochondrial membrane potential and the increase of intracellular Ca2+ concentration indicated compound 1 had the excellent antitumor activity. Especially for compound 1 , the molecular docking suggested that 4-Leu residue and isoindolinone fragments presented stronger binding with MDM2 oncoprotein of liver cancer cells, which plays an important role in the stability of MDM2 ligands. [Display omitted] [ABSTRACT FROM AUTHOR]

Photoinduced single electron transfer (SET) cyclization processes for synthesis of a Sansalvamide A analog containing double pharmacophores (cyclicpeptides and O-phthalimide moiety) is described to develop novel antitumor cyclopeptide drug. The resultant compound is active in drug-sensitive HeLa, HepG-2 and MCF-7 cell lines. Specifically, the title compound was found to inhibit MCF-7 cells with an IC 50 value of 15 μM (13.4 μg/mL), which may serve as a potential candidate for antitumor drug development. [ABSTRACT FROM AUTHOR]

In order to obtain inexpensive Pt-free counter electrode materials for dye-sensitized solar cells and expand the application fields of low-rank coal, lignite-based Ni/C composite was prepared by low-medium temperature pyrolysis method using Huolinhe lignite as raw materials. The structure and chemical components of as-synthesized lignite-based Ni/C composite was characterized by XRD, FT-IR, TG, Raman, SEM, TEM, and XPS, and the electrocatalytic activity of lignite-based Ni/C composite counter electrode was investigated by cyclic voltammetric curve, electrochemical impedance spectrum, and Tafel polarization curve. It is found that the electrocatalytic activity of the lignite was improved after low-medium temperature pyrolysis and composited with Ni species to form lignite-based Ni/C composite, which helps to catalyze the reduction of electrolyte and thus improve the photoelectric conversion efficiency of the solar cells. The photoelectric conversion efficiency (η) of the dye-sensitized solar cells based on the lignite-based Ni/C composite counter electrode was 3.42% (Jsc = 11.49 mA cm−2, Voc = 0.75 V, FF = 0.40) significantly higher than that of the lignite counter electrode (η = 0.20%, Jsc = 3.16 mA cm−2, Voc = 0.72 V, FF = 0.09). This indicates that low-medium temperature pyrolysis and composition with Ni are an effective method to improve the photovoltaic performance of lignite-based counter electrode materials. The lignite-based Ni/C composite was synthesized and applied in counter electrode for DSSCs. [ABSTRACT FROM AUTHOR]

In the field of dye‐sensitized solar cells (DSSCs), although Pt is commonly used as counter electrode materials owing to its great electrocatalytic activity and conductivity, the high price and small reserves of Pt limit its large‐scale application. In this paper, heteromorphic Ni decorated Fe‐containing carbon nanofibers (Ni/NiO@Fe‐CNFs) was prepared by a thermal synthesis method, and applied as composite counter electrode materials for DSSCs. It was found that the as‐synthesized Ni/NiO@Fe‐CNFs shows better electrocatalytic activity than that of Fe‐CNFs and CNFs for the reduction reaction of triiodide to iodide. The improved electrocatalytic activity is not only attributed to the introduction of Fe2O3 to form Fe‐CNFs, but also attributed to the heteromorphic Ni decoration and their synergistic effect. The photoelectric conversion efficiency of DSSCs with Ni/NiO@Fe‐CNFs counter electrode is 4.81 %, much higher than that of CNFs (0.62 %) and Fe‐CNFs counter electrode (3.65 %), and comparable to the value of Pt counter electrode (5.10 %). Accordingly, the Ni/NiO@Fe‐CNFs is expected to be a potential counter electrode material to replace Pt. [ABSTRACT FROM AUTHOR]

Cyclic peptides has become an attractive modality for drug development due to their excellent binding affinity, target selectivity and low toxicity, however significant activity difference between the synthetic and natural cyclic peptides such as Phakillestatins has puzzled chemists for years. In an effort to explore the bioactive secondary structures, three pairs of cyclic Phakellistatin 6 analogs with special constrained stereo-features were prepared by regioselectively controlled intramolecular photoinduced single electron transfer (SET) reactions in this paper. The spatial configurationally features were systematically investigated by ECD and NMR, together with detailed structural analysis based on theoretical calculations, which showed that conventional turns rather than irregular γ-/β-turn secondary structures played important roles for the antitumor activities. We also presented the in vitro bioactive assay, liposomal leakage assays and electron microscopy analyses, which indicated the prepared cyclopeptide analogs excellent antitumor activities, most showing greater growth inhibitory effects than that of the famous anticancer agent paclitaxel. Image 1 • Novel Phakellistatin 6 analogs were stereoselectively synthesized by photoinduced cyclization. • Their absolute configurations were determined by experimental and theoretical ECD spectra. • The spatial configurationally features affecting the antitumor activities were elucidated in detail. [ABSTRACT FROM AUTHOR]

Cyclic peptides combine several favorable properties such as good binding affinity, target selectivity and low toxicity that make them an attractive modality for drug development. In an effort to identify what conformation could be accounting for the bioactive disparity of natural and synthetic cyclic peptides, some structurally-constrained analogs of cyclopeptide Axinastatin 3 were prepared by photo-induced single electron transfer (SET) reaction. Detailed stereochemistry study was performed by experimental electronic circular dichroism combined with theoretical calculations. Our study suggested that the cyclopeptide 1 with βI-turn presented stronger antitumor activity comparing with those without such secondary structures. Moreover, a rare 'π helix unit' (compound 3) was realized because of the constrained cyclic structure, which could be considered an important research object for future study of unique helix secondary structures. [ABSTRACT FROM AUTHOR]

Cyclic peptides have become a powerful modality in drug development. Naturally isolated cyclic peptides such as phakellistatins have been found to have broad-spectrum bioactivity. In this paper, we have prepared an analog of phakellistatin 18, and tried to compare its bioactivity with that of our reported phakellistatin 2 analog. It was found that compound 1 derived from phakellistatin 18 showed inferior inhibiting ability compared to the phakellistatin 2 analog, similar to the phenomenon observed in the natural products (phakellistatin 2 presented stronger antitumor activity than that of phakellistatin18). We have performed molecular docking of the two analogs with the MDM2 protein using AutoDock Tools, which showed that the phakellistatin 2 analog presented stronger binding through a H-bond, providing an explanation for the bioactivity difference. [ABSTRACT FROM AUTHOR]

Electrochemical water splitting is considered a green and sustainable method of producing hydrogen energy. Herein, to pursue a highly efficient hydrogen evolution reaction, we fabricated high-performance electrocatalysts, by utilizing a bimetallic (Cu and Co) metal–organic framework to modify rGO through a one-step in situ approach. The synthesized CuCoOC@rGO presents a highly ordered structure with a defect-rich porous surface for the hydrogen evolution reaction (HER). Specifically, the appropriate adjustment of metal (Cu and Co), 1,3,5-benzenetricarboxylic acid (H3BTC), and rGO ratios leads to a well-defined morphology, which creates a defect-rich porous surface. Characterized by XRD, SEM, EDS, FT-IR spectroscopy, Raman spectroscopy, XPS, and BET, the morphology exposes more active sites, strong evidence for the promotion of electrocatalytic efficiency. Upon the analysis of the experimental data, the obtained CuCoOC@rGO catalyst exhibits excellent activity in alkaline media with a low overpotential of 120 mV at a current density of 10 mA cm−2, and a Tafel slope of 124 mV dec−1 for the hydrogen evolution reaction (HER). Guided by the structure–activity relationship, the superior HER activity of CuCoOC@rGO in alkaline electrolyte could originate from many sources, including: (1) as a self-supported substrate, CuCoOC@rGO not only leads to profitable electrical contact and mechanical stability but also firmly roots into the rGO without extra binders. (2) The highly ordered structure provides smooth ion and electron transport channels, which are conducive to electrolyte infiltration and gas release. (3) The abundance of defective pores on the surface of the nanoarrays, which offers more active sites for the catalytic process. This study provides new prospects for the rational design and fabrication of advanced hierarchical functional electrocatalysts for application in electrochemical energy devices. [ABSTRACT FROM AUTHOR]

To screen out suitable electrode materials and overcome the shortcomings of the existed electrode materials for the application in dye-sensitized solar cells and supercapacitors, NiS 2 /reduced graphene oxide (NiS 2 /rGO) composite material was prepared by a simple one-step hydrothermal method in this paper and applied in the field of both dye-sensitized solar cells and supercapacitors as electrode material. In an electrolyte of 6 M KOH, the NiS 2 /rGO composite material with bilayer capacitance characteristics exhibited a high specific capacitance of 259.20 F g−1 at the current density of 0.6 A g−1, which was significantly higher than that of rGO (188.94 F g−1). Moreover, at a current density of 2 A g−1, the NiS 2 /rGO composite material had 92.85% capacitance retention after 2000 cycles. When applied as counter electrode material for the dye-sensitized solar cells, the NiS 2 /rGO composite material counter electrode exhibited a satisfactory photoelectric conversion efficiency (η) of 3.16% under standard simulated sunlight (AM 1.5 G), which was significantly higher than that of single rGO counter electrode (improved by 90.40%). The NiS 2 /rGO composite electrode material prepared by a simple one-step hydrothermal method is a potential bi-functional composite electrode materials for both dye-sensitized solar cells and supercapacitors. [Display omitted] • NiS 2 /reduced graphene oxide composite was prepared by one-step hydrothermal method. • NiS 2 /reduced graphene oxide exhibits excellent electrochemical performance. • High photoelectric conversion efficiency was obtained for dye sensitized solar cells. • Excellent specific capacitance and durability were obtained for supercapacitors. [ABSTRACT FROM AUTHOR]

Type 2 diabetes mellitus (T2DM), a complex metabolism disease, which was characterized by metabolic disorders including hyperglycemia, has become a major health problem due to the increasing prevalence worldwide. γ-glutamylcysteine (γ-GC) as an immediate precursor of glutathione (GSH) was originally used for the treatment of sepsis, inflammation bowel disease, and senescence. Here, we evaluated the capacity of γ-GC on diabetes-related metabolic parameters in db/db mice and insulin resistance (IR) amelioration in cells induced by palmitic acid (PA). Our data suggested that γ-GC treatment decreased body weight, reduced adipose tissue size, ameliorated ectopic fat deposition in liver, increased the GSH content in liver, improved glucose control and other diabetes-related metabolic parameters in vivo. Moreover, in vitro experiments showed that γ-GC could maintain the balance of free fatty acids (FFAs) and glucose uptake through regulating the translocation of CD36 and GLUT4 from cytoplasm to plasma membrane. Furthermore, our finding also provided evidence that γ-GC could activate Akt not only via adenylate cyclase (AC)/cAMP/PI3K signaling pathway, but also via IGF-1R/IRS1/PI3K signaling pathway to improve IR and hepatic steatosis. Blocking either of two signaling pathways could not activate Akt activation induced by γ-GC. This unique characteristic ensures the important role of γ-GC in glucose metabolism. Collectively, these results suggested that γ-GC could serve as a candidate dipeptide for the treatment of T2DM and related chronic diabetic complications via activating AC and IGF-1R/IRS1/PI3K/Akt signaling pathways to regulate CD36 and GLUT4 trafficking. [ABSTRACT FROM AUTHOR]