Fe2 O+ Cation Mediated Propane Oxidation by Dioxygen in the Gas Phase.

The mass-selected Fe2 O+ cation mediated propane oxidation by O2 was investigated by mass spectrometry and density functional theory calculations. In the reaction of Fe2 O+ with C3 H8 , H2 was liberated by C-H bond activation to give Fe2 OC3 H6+ . Interestingly, when a mixture of C3 H8 /O2 was introduced into the reactor, an intense signal that corresponded to the Fe2 O2+ cation was present; the experiments indicated that O2 was activated in its reaction with Fe2 O(C3 H6 )+ to give Fe2 O2+ and C3 H6 O (acetone or propanal). A Langmuir-Hinshelwood-like mechanism was adopted in the propane oxidation reaction by O2 on gas-phase Fe2 O+ cations. In comparison with the absence of Fe2 O2+ in the reaction of Fe2 O+ with O2 , the ligand effect of C3 H6 on Fe2 OC3 H6+ is important in the oxygen activation reaction. The theoretical results are consistent with the experimental observations. The propane oxidation by O2 in the presence of Fe2 O+ might be applied as a model for alkane and O2 activations over iron oxide catalysts, and the mechanisms and kinetic data are useful for understanding corresponding heterogeneous reactions.

Direct hydroxylation of benzene to phenol mediated by nanosized vanadium oxide cluster ions at room temperature.

Gas-phase vanadium oxide cluster cations and anions are prepared by laser ablation. The small cluster ions (<1000 amu) are mass-selected using a quadrupole mass filter and reacted with benzene in a linear ion trap reactor; large clusters (>1000 amu) with no mass selection are reacted with C6H6 in a fast flow reactor. Rich product variety is encountered in these reactions, and the reaction channels for small cationic and anionic systems are different. For large clusters, the reactivity patterns of (V2O5) n+ (n = 6-25) and (V2O5) n O- (n = 6-24) cluster series are very similar to each other, indicating that the charge state has little influence on the oxidation of benzene. In sharp contrast to the dramatic changes of reactivity of small clusters, a weakly size dependent reaction behavior of large (V2O5)6-25+ and (V2O5)6-24O- clusters is observed. Therefore, the charge state and the size are not the major factors influencing the reactivity of nanosized vanadium oxide cluster ions toward C6H6, which is not common in cluster science. In the reactions with benzene, the small and large reactive vanadium oxide cations show similar reactivity of hydroxyl radicals (OH•) toward C6H6 at higher and lower temperatures, respectively; different numbers of vibrational degrees of freedom and the released energy during the formation of adduct complexes can explain this intriguing correlation. The reactions investigated herein might be used as the models of how to realize the partial oxidation of benzene to phenol in a single step, and the observed mechanisms are helpful to understand the corresponding heterogeneous reactions, such as those over vanadium oxide aerosols and vanadium oxide catalysts.

Liberation of three dihydrogens from two ethene molecules as mediated by the tantalum nitride anion cluster Ta3N2- at room temperature.

The reactivity of gas-phase cluster anions Ta3N2- with C2H4 under thermal collision conditions was studied by mass spectrometry in conjunction with density functional theory calculations. The full dehydrogenation of the C2H4 molecule was observed, with the formation of two dihydrogen molecules. Interestingly, the two carbon atoms originating from the first C2H4 molecule are used to construct another cluster Ta3N2C2-, which can activate one more C2H4 releasing one H2 molecule. Therefore, three dihydrogen molecules are liberated from two ethene molecules in the overall reaction. The full dehydrogenation of C2H4 by gas-phase anions as well as the structure and reactivity of M-N-C (M: transition metal) cluster is reported for the first time. The properties of Ta3N2- and Ta3N2C2- elucidated herein are of use in providing fundamental information that is necessary to tailor the design of new and effective catalysts by applying the related materials.

Origin of the Different Reactivity of the Triatomic Anions HMoN- and ZrNH- toward Alkane: Compositions of the Active Orbitals.

The reactivity of the triatomic anions HMoN- and ZrNH- toward alkanes was investigated by means of mass spectrometry in conjunction with density functional theory calculations. HMoN- can activate C-H bond of ethane with the liberation of ethene and hydrogen molecules, and the generation of hydrogen molecules is the major reaction channel; however, no C-H bond activation of ethane was observed over ZrNH- ion, and the density functional theory calculations suggest this pathway is hampered by intrinsic energy barrier. In sharp contrast, another triatomic anion HNbN- can bring about methane activation under thermal conditions, as reported previously. A strong dependence of the chemical reactivity of alkane activation on compositions of active orbitals in the above-mentioned systems is discussed. This combined experimental/computational study may provide new insights into the importance of compositions of active orbitals and their essential role in the reactions of related systems with alkanes.

SIRT3 alleviates high glucose-induced chondrocyte injury through the promotion of autophagy and suppression of apoptosis in osteoarthritis progression.

A growing amount of epidemiological evidence proposes diabetes mellitus (DM) to be an independent risk factor for osteoarthritis (OA). Sirtuin 3 (SIRT3), which is mainly located in mitochondria, belongs to the family of nicotinamide adenine dinucleotide (NAD+)-dependent protein deacetylases and is involved in the physiological and pathological processes of cell regulation. The aim of this study was to investigate the effects of SIRT3 on diabetic OA and underlying mechanisms in the prevention of type 2 DM (T2DM)-induced articular cartilage damage. High-fat and high-sugar diets combined with streptozotocin (STZ) injection were used for establishing an experimental T2DM rat model. The destabilization of medial meniscus (DMM) surgery was applied to induce the rat OA model. Primary rat chondrocytes were cultivated with a concentration of gradient glucose. Treatment with intra-articular injection of SIRT3 overexpression lentivirus was achieved in vivo, and intervention with SIRT3 knockdown was performed using siRNA transfection in vitro. High glucose content was found to activate inflammatory response, facilitate apoptosis, downregulate autophagy, and exacerbate mitochondrial dysfunction in a dose-dependent manner in rat chondrocytes, which can be deteriorated by SIRT3 knockdown. In addition, articular cartilage damage was found to be more severe in T2DM-OA rats than in DMM-induced OA rats, which can be mitigated by the intra-articular injection of SIRT3 overexpression lentivirus. Targeting SIRT3 is a potential therapeutic strategy for the alleviation of diabetic OA.

Black phosphorus stabilized by titanium disulfide and graphite via chemical bonds for high-performance lithium storage.

Black phosphorus (BP) anode has received extensive attentions for lithium-ion batteries (LIBs) due to its ultrahigh theoretical specific capacity (2596 mAh g-1) and superior electronic conductivity (≈102 S m-1). However, the enormous volume variations during lithiation/delitiation processes greatly limit its applications. Herein, a new BP-titanium disulfide-graphite (BP-TiS2-G) nanocomposite composed of BP, titanium disulfide and graphite has been prepared by a facile and scalable high-energy ball milling method. The experimental data proves that PC and PS bonds have been successfully introduced at the interface, which can effectively maintain the structural integrity of the BP-TiS2-G electrode when evaluated as an anode material for LIBs. In addition, lithium-ion diffusion kinetics have been demonstrated to be enhanced from the synergistic effect of PC and PS bonds. As a result, the BP-TiS2-G anode shows outstanding cycling stability (906.2 mAh g-1 after 1300 cycles at 1.0 A g-1) and superior rate performance (313.8 mAh g-1 at 10.0 A g-1). Our work shows the synergistic effects of different chemical bonds to stabilize BP can be a potential strategy for the development of high-performance alloy-type anodes for rechargeable batteries.

Study on the optimization of temperature uniformity in the oven under the forced convection mode.

In order to study the temperature distribution in a multi-functional oven and optimize the structural parameters of the oven, the internal temperature uniformity was improved. The test was conducted and the numerical simulation was conducted in two ways. The distribution of temperature field in each layer of ovens was measured in real time using a 13-point distributed thermocouple, and the oven temperature uniformity index was measured and analyzed. The temperature field inside the oven was numerically simulated using computational fluid dynamics. Investigated the heat conduction, convection and radiation effects respectively, and found out the main heat transfer mode of the oven. Further through the test of temperature measurement, verify the accuracy of the numerical simulation method. According to the results of the experiment and simulation, the reason of the uneven temperature field in the original structure of the oven was revealed and analyzed. By changing the structure of the oven tailgate, adjusting the air volume distribution, changing the distribution of the air outlet and other measures, greatly improving the uniformity of the temperature field inside the oven.

Propensity score-matched analysis of enhanced recovery after surgery in total hip arthroplasty for displaced femoral neck fractures.

OBJECTIVE: The concept of enhanced recovery after surgery (ERAS) has been proposed in recent years, which indeed bring about evident convenience for the patients. This prospective cohort study was aimed to investigate the impact of ERAS on the clinical outcome of patients who undergoing total hip arthroplasty due to displaced femoral neck fractures. METHODS: Patients in two periods were included in our research, before ERAS (n = 194) and after ERAS (n = 65). The clinical outcome, such as patient statistics, details of perioperative management, length of stay (LOS), pain, Harris hip score, in-hospital complications, and interim postoperative survival were collected. This retrospective observational study addressed confounding bias using propensity score matching (PSM) analysis. RESULTS: With PSM, 55 pairs of well-matched patients were generated for comparison (conventional vs. ERAS). LOS decreased to 13.0 ± 3.2 days for the ERAS group, compared to 15.7 ± 3.5 days in the conventional group. VAS pain scores decreased significantly in both groups, and the decrease in the ERAS group was more significant than that in the conventional group at 3, 7, and 14 days postoperatively. The Harris scores of both groups significantly improved, but were better for the ERAS group than the conventional group at 7 and 14 days and 1 month postoperatively. However, no significant difference was observed at 6 months postoperatively. Additionally, the incidence of complications during hospitalization was lower in the ERAS group than that in the conventional group. No significant difference was observed in the medium-term survival between the two groups. CONCLUSIONS: ERAS apparently benefit patients in early rehabilitation by reducing complications and shortening hospital stays but not for the long-term hip function or survival.

Gambogenic acid induces cell death in human osteosarcoma through altering iron metabolism, disturbing the redox balance, and activating the P53 signaling pathway.

Osteosarcoma (OS) is the most common primary bone malignancy in children and adolescents with extremely poor prognosis. Gambogenic acid (GNA), one of the major bioactive ingredients isolated from Gamboge, has been shown to possess a multipotent antitumor effect, its activity on OS remains unclear yet. In this study, we found that GNA could trigger multiple cell death modalities, including ferroptosis and apoptosis in human OS cells, reduce the cell viability, inhibit the proliferation and invasiveness. Furthermore, GNA provoked oxidative stress leading to GSH depletion-inducing ROS generation and lipid peroxidation, altered iron metabolism represented by the induction of labile iron, mitochondrial membrane potential decreased, mitochondrial morphological changed, decreased the cell viability. In addition, ferroptosis inhibitors (Fer-1) and apoptosis inhibitors (NAC) can partially reversed GNA' s effects on OS cells. Further investigation showed that GNA augmented the expression of P53, bax, caspase 3 and caspase 9 and decreased the expression of Bcl-2, SLC7A11 and glutathione peroxidase-4 (GPX4). In vivo, GNA was showed to delay tumor growth significantly in axenograft osteosarcoma mouse model. In conclusion, this study reveals that GNA simultaneously triggers ferroptosis and apoptosis in human OS cells by inducing oxidative stress via the P53/SLC7A11/GPX4 axis.

A Covalent Heterostructure of Metal Phosphide Quantum Dots Anchored in N, P Co-doped Carbon Nanocapsules for Fast and Durable Lithium Storage.

Transition-metal phosphides (TMPs) anodes for lithium ion batteries (LIBs) usually show poor rate capability and rapid capacity degradation owing to their low electronic conductivities, huge volumetric changes, as well as inferior reversibility of the discharge product Li3P. Herein, a covalent heterostructure with TMPs quantum dots anchored in N, P co-doped carbon nanocapsules (NPC) has been prepared in which the P element in TMPs is simultaneously doped into the carbon matrix. As a proof of concept, Co2P quantum dots covalently anchored in NPC (Co2P QDs/NPC) is prepared and evaluated as an anode for LIBs. The Co2P QDs/NPC electrode not only demonstrates a high capacity and an extraordinary rate performance but also delivers an impressive cyclability with a high capacity retention of 102.5% after 1600 cycles, one of the best reported values for TMPs-based electrode materials for LIBs. The covalent heterostructure can facilitate the electron/ion transfer and maintain the structural stability during the intensive cycles. Moreover, density functional theory calculations demonstrate that the interfacial covalent coupling can enhance the electrochemical reversibility of the discharge product Li3P in the charge processes via lowering the conversion reaction energies. This work presents an effective interfacial engineering strategy for developing high-performance TMPs anodes for advanced LIBs.

Caprin-1 promotes HepG2 cell proliferation, invasion and migration and is associated with poor prognosis in patients with liver cancer.

The present study aimed to investigate the role of caprin-1 in liver cancer and its association with the clinicopathological features and prognosis of liver cancer, as well as the underlying mechanism of caprin-1 function. Caprin-1 expression levels in a tissue microarray containing 40 liver cancer tissues, 10 peritumoral tissues and 20 normal liver tissues were analyzed using immunohistochemistry. The clinical data of 154 patients with liver cancer were also collected from The Cancer Genome Atlas database. Kaplan-Meier analysis and a Cox proportional hazards regression model were used to assess the association between caprin-1 expression levels and survival in patients with liver cancer. The effects of caprin-1 knockdown on the mRNA levels of cyclin D1 and cyclin D2 as well as the proliferation, invasion and migration of HepG2 cells were also investigated. The expression level of caprin-1 in liver cancer tissues was significantly higher compared with normal liver tissues or cells (P<0.01). High caprin-1 expression levels were associated with advanced clinical stage (P<0.001) and enhanced tumor invasion (P<0.001). Kaplan-Meier analysis showed that the overall survival time and disease-free survival time in patients with liver cancer with high caprin-1 expression were significantly shorter compared with patients with low caprin-1 expression levels (P=0.002 and P=0.033, respectively). The Cox proportional hazards regression model showed that high caprin-1 expression levels were an independent prognostic factor for liver cancer (P<0.001). Knockdown of caprin-1 in HepG2 cells significantly downregulated mRNA expression levels of cyclin D1 and cyclin D2, inhibited cell proliferation and invasion and the cells were arrested at G0/G1 phase. In conclusion, caprin-1 may be a novel prognostic indicator for patients with liver cancer.

Ultrasound-mediated delivery of RGD-conjugated nanobubbles loaded with fingolimod and superparamagnetic iron oxide nanoparticles: targeting hepatocellular carcinoma and enhancing magnetic resonance imaging.

Nanobubbles (NBs) are considered to be a new generation of ultrasound-responsive nanocarriers that can effectively target tumors, accurately release multi-drugs at desired locations, as well as simultaneously perform diagnosis and treatment. In this study, we designed theranostic NBs (FTY720@SPION/PFP/RGD-NBs) composed of RGD-modified liposomes as the shell, and perflenapent (PFP), superparamagnetic iron oxide nanoparticles (SPION), and fingolimod (2-amino-2[2-(4-octylphenyl)ethyl]-1,3-propanediol, FTY720) encapsulated as the core. The prepared FTY720@SPION/PFP/RGD-NBs were black spheres with a diameter range of 160-220 nm, eligible for enhanced permeability and retention (EPR) effects. The calculated average drug loading efficiency (LE) and encapsulation efficiency (EE) of the FTY720@SPION/PFP/RGD-NBs were 9.18 ± 0.61% and 88.26 ± 2.31%, respectively. With the promotion of low-intensity focused ultrasound (LIFU), the amount and the rate of FTY720 released from the prepared NB complex were enhanced when compared to the samples without LIFU treatment. In vitro magnetic resonance imaging (MRI) trials showed that the prepared FTY720@SPION/PFP/RGD-NBs had a high relaxation rate and MRI T2-weighted imaging (T2WI) scanning sensitivity conditions. The cell viability studies demonstrated that both HepG2 and Huh7 cells co-cultured with FTY720@SPION/PFP/RGD-NB (100 µg mL-1) + LIFU treatment had the lowest survival rate compared with the other groups at 24 h and 48 h, showing that FTY720@SPION/PFP/RGD-NB had the strongest anti-tumor efficiency among the prepared NBs. The cytotoxicity study also demonstrated that the prepared NBs had low toxicity to normal fibroblast 3T3 cells. Cellular uptake studies further indicated that both LIFU treatment and RGD modification could effectively improve the tumor-targeted effects, thereby enhancing the antitumor efficacy. The qRT-PCR results indicated that LIFU-mediated FTY720@SPION/PFP/RGD-NB could significantly cause the activation of Caspase3, Caspase9 and p53 compared to the control group, inducing HepG2 apoptosis. These results together indicated that FTY720@SPION/PFP/RGD-NBs combined with LIFU may serve as a multifunctional drug delivery platform for hepatocellular carcinoma treatment and provide a new strategy for tumor visualization by MRI.

A rings-in-pores net: crown ether-based covalent organic frameworks for phase-transfer catalysis.

We herein present a new family of crown ether-based covalent organic frameworks (CE-COFs) for the first time. The CE-COFs show excellent phase-transfer catalytic performance in various nucleophilic substitution reactions.

PIN1 Inhibition Sensitizes Chemotherapy in Gastric Cancer Cells by Targeting Stem Cell-like Traits and Multiple Biomarkers.

Gastric cancer is the third leading cause of cancer-related death worldwide. Diffuse type gastric cancer has the worst prognosis due to notorious resistance to chemotherapy and enrichment of cancer stem-like cells (CSC) associated with the epithelial-to-mesenchymal transition (EMT). The unique proline isomerase PIN1 is a common regulator of oncogenic signaling networks and is important for gastric cancer development. However, little is known about its roles in CSCs and drug resistance in gastric cancer. In this article, we demonstrate that PIN1 overexpression is closely correlated with advanced tumor stages, poor chemo-response and shorter recurrence-free survival in diffuse type gastric cancer in human patients. Furthermore, shRNA-mediated genetic or all-trans retinoic acid-mediated pharmaceutical inhibition of PIN1 in multiple human gastric cancer cells potently suppresses the EMT, cell migration and invasion, and lung metastasis. Moreover, PIN1 genetic or pharmaceutical inhibition potently eliminates gastric CSCs and suppresses their self-renewal and tumorigenicity in vitro and in vivo Consistent with these phenotypes, are that PIN1 biochemically targets multiple signaling molecules and biomarkers in EMT and CSCs and that genetic and pharmaceutical PIN1 inhibition functionally and drastically enhances the sensitivity of gastric cancer to multiple chemotherapy drugs in vitro and in vivo These results demonstrate that PIN1 inhibition sensitizes chemotherapy in gastric cancer cells by targeting CSCs, and suggest that PIN1 inhibitors may be used to overcome drug resistance in gastric cancer.

Arbuscular mycorrhizal fungal community composition affected by original elevation rather than translocation along an altitudinal gradient on the Qinghai-Tibet Plateau.

Elucidating arbuscular mycorrhizal (AM) fungal responses to elevation changes is critical to improve understanding of microbial function in ecosystems under global asymmetrical climate change scenarios. Here we examined AM fungal community in a two-year reciprocal translocation of vegetation-intact soil blocks along an altitudinal gradient (3,200 m to 3,800 m) in an alpine meadow on the Qinghai-Tibet Plateau. AM fungal spore density was significantly higher at lower elevation than at higher elevation regardless of translocation, except that this parameter was significantly increased by upward translocation from original 3,200 m to 3,400 m and 3,600 m. Seventy-three operational taxonomic units (OTUs) of AM fungi were recovered using 454-pyrosequencing of 18S rDNA sequences at a 97% sequence similarity. Original elevation, downward translocation and upward translocation did not significantly affect AM fungal OTU richness. However, with increasing altitude the OTU richness of Acaulosporaceae and Ambisporaceae increased, but the OTU richness of Gigasporaceae and Glomeraceae decreased generally. The AM fungal community composition was significantly structured by original elevation but not by downward translocation and upward translocation. Our findings highlight that compared with the short-term reciprocal translocation, original elevation is a stronger determinant in shaping AM fungal community in the Qinghai-Tibet alpine meadow.

Crossover from capillary fingering to viscous fingering for immiscible unstable flow:Experiment and modeling.

Invasion percolation with trapping (IPT) and diffusion-limited aggregation (DLA) are simple fractal models, which are known to describe two-phase flow in porous media at well defined, but unphysical limits of the fluid properties and flow conditions. A decade ago, Fernandez, Rangel, and Rivero predicted a crossover from IPT (capillary fingering) to DLA (viscous fingering) for the injection of a zero-viscosity fluid as the injection velocity was increased from zero. [Phys. Rev. Lett. 67, 2958 (1991)]]. We have performed experiments in which air is injected into a glass micromodel to displace water. These experiments clearly demonstrate this crossover as the injection velocity of the air is increased. Furthermore, simulations, using our standard pore-level model, also support the predicted IPT-to-DLA crossover, as well as the predicted power-law behavior of the characteristic crossover length.

A novel UPLC/MS/MS method for rapid determination of metapristone in rat plasma, a new cancer metastasis chemopreventive agent derived from mifepristone (RU486).

Mifepristone (RU486) is a chemical abortifacient used by hundreds of millions of women world-wide. It has recently been used in clinical trials for psychotic depression and cancer chemotherapy. Metapristone is the most predominant biological active metabolite of mifepristone, and being developed as a novel cancer metastasis chemopreventive agent based on its unique pharmacological properties. In this study, a novel rapid and sensitive method using UPLC/MS/MS was developed and validated for quantitative analysis of metapristone in plasma, which used less plasma volume and was demonstrated to be more simple and low-cost than the published methods. Metapristone in plasma was recovered by liquid-liquid extraction using 1 mL of ethyl acetate and chromatographic separation was carried on a C18 column at 35 °C, with a gradient mobile phase consisting of methanol and water containing 0.1% (v/v) formic acid at a flow rate of 0.3 mL/min. The mass spectrometric detection was carried out using a triple-quadrupole system via positive electrospray ionization. Multiple reaction monitoring was used for quantitation of m/z transitions from 416.3 to 119.9 for metapristone and from 313.1 to 109 for levonorgestrel (internal standard). Good linearity (r²> 0.9926) was achieved over a concentration range from 7.1 to 2840 ng/mL with a lower limit of quantification of 7.1 ng/mL for metapristone. The intra- and inter-day variations of the assay were 2.4-10.0% relative standard deviation with an accuracy of -5.6 to 8.6% relative error. This newly developed method was successfully applied to a pharmacokinetic study that revealed, for the first time, that there was a significant difference in pharmacokinetic profile between genders.

In vitro and in vivo anticancer activity evaluation of ursolic acid derivatives.

Twenty-three ursolic acid (1) derivatives 2-24 (ten novel compounds 8-10, 14-17 and 22-24) modified at the C-3 and the C-28 positions were synthesized, and their structures were confirmed by IR, (1)H NMR, MS, and elemental analysis. The single crystals of compounds 15 and 17 were obtained. The cytotoxic activity of the derivatives was evaluated against HepG2, BGC-823, SH-SY5Y, HeLa and HELF cells by the MTT assay. The induction of apoptosis and affects on the cell cycle distribution with compound 14 were assessed by fluorescence microscopy, flow cytometry and the activity of caspase-3 in HepG2 cells. Compounds 14-17 had more significant antiproliferative ability against the four cancer cell lines and low cytotoxicity to human embryonic lung fibroblast cells (HELF). Compounds 11, 14-16, 21 and 23 were particularly active against HepG2 cell growth. Compound 14 was selected to investigate cell apoptosis and cell cycle distribution. Flow cytometric analysis and morphologic changes of the cell exhibited that treatment of HepG2 cells with compound 14 led to cell apoptosis accompanied by cell cycle arrest at the S phase in a dose-dependent manner. Furthermore, the activity of the caspase-3 enzyme was increased in the treated cells. In vivo studies using H22 xenografts in Kunming mice were conducted with compound 14 at doses of 50, 100 and 150 mg/kg body weight. The results revealed that the medium dosage group (100 mg/kg) showed significant anticancer activity (45.6 ± 4.3%) compared to the control group.