TPP Effect Research Articles

Synthesis and comparative analysis of the cytotoxicity and mitochondrial effects of triphenylphosphonium and F16 maslinic and corosolic acid hybrid derivatives

The cytotoxic profile and antiproliferative and mitochondrial effects of triterpene acid conjugates with mitochondriotropic lipophilic triphenylphosphonium (TPP+) and F16 cations were evaluated. Maslinic and corosolic acids chosen as the investigation objects were synthesized from commercially available oleanolic and ursolic acids. Study of the cytotoxic activity of TPP+ and F16 triterpenoid derivatives against six tumor cell lines demonstrated a comparable synergistic effect in the anticancer activity, which was most pronounced in the case of MCF-7 mammary adenocarcinoma cells and Jurkat and THP-1 leukemia cells. The corosolic and maslinic acid hybrid derivatives caused changes in the progression of tumor cell cycle phases when present in much lower doses than their natural triterpene acid precursors. The treatment of tumor cell lines with the conjugates resulted in the cell cycle arrest in the G1 phase and increase in the cell population in the subG1 phase. The cationic derivatives of the acids were markedly superior to their precursors as inducers of hyperproduction of reactive oxygen species and more effectively decreased the mitochondrial potential in isolated rat liver mitochondria. We concluded that the observed cytotoxic effect of TPP+ and F16 triterpenoid conjugates is attributable to the ability of these compounds to initiate mitochondrial dysfunctions. Their cytotoxicity, antiproliferative action, and mitochondrial effects depend little on the type of cationic groups used.

Self-healing and corrosion-sensing multifunctional coatings containing pH-sensitive TiO2-based composites

Polyelectrolyte-encapsulated nanocontainers can effectively respond to changes of pH and thus control the on-demand release of corrosion inhibitors. A pH-responsive release system (Phen-Tpp@MTNs-PDDA) was developed based on the cationic polyelectrolyte poly dimethyl diallyl ammonium chloride (PDDA) encapsulated mesoporous TiO2 nanocontainers (MTNs) loaded with 1,10-phenanthroline (Phen) and tripolyphosphate ions (Tpp) corrosion inhibitors. The epoxy coating (EP) embedded with Phen-Tpp@MTNs-PDDA (Phen-Tpp@MTNs-PDDA/EP) demonstrates superior self-healing properties and confers long-term protection on the metal substrate through the cooperative effect of Phen and Tpp. Simultaneously, this hybrid coating is endowed with corrosion sensing capability based on the color development originating from the interaction of Phen and carbon steel. This self-healing and corrosion-sensing multifunctional coating provides an effective strategy for the corrosion protection of metals.

Surface modification of carbon-based materials using a double dielectric barrier discharge for efficient removal of OPFRs with different polarity

This article utilizes a double dielectric barrier discharge (DBD) technology to enhance the removal of five commonly found highly toxic organophosphorus flame retardants (OPFRs) by modifying carbon-based materials. This study investigated the adsorption performance of carbon-based materials modified under various discharge times, frequencies, and voltage conditions on five different OPFRs. Before the modification, the adsorption amount of TPP was only 0.56 mg/g, but the modification significantly improved the adsorption effect of TPP to 14.8 mg/g. Furthermore, the overall adsorption amount of the flame retardants with five different polarities increased by 70.51 mg/g. The study also examined the adsorption kinetics and isotherms, the dosage effect, and the adsorption mechanism and reusability of the modified carbon materials for OPFRs. In the end, the study found that the optimal adsorption capacity for 5 types of OPFRs was achieved at a voltage frequency of 8 kHz, a voltage of 12 kV, and 15 min. The fitting kinetic and isotherm model determines that chemical adsorption is the main mechanism supplemented by physical adsorption, and Langmuir and Freundlich provide better fitting for the adsorption isotherms. The material exhibits a favorable pore structure, high adsorption capacity, and stable regenerative adsorption performance. The adsorption mechanism for OPFRs involves pore filling, hydrogen bonding, π - π conjugation, and strong electrostatic interaction. The optimal adsorption capacity is 109.81 mg/g. This study provides a new strategy for synthesizing activated carbon materials with broad polarity. The relative standard deviation of all experiments did not exceed 2.88 %.

Fluorinated triphenylphosphonium analogs improve cell selectivity and invivo detection of mito-metformin.

Triphenylphosphonium (TPP+) conjugated compounds selectively target cancercells by exploiting their hyperpolarized mitochondrial membrane potential. Todate, studies have focused on modifying either the linker or the cargo of TPP+-conjugated compounds. Here, we investigated the biological effects ofdirect modification to TPP+ to improve the efficacy and detection of mito-metformin (MMe), a TPP+-conjugated probe we have shown to have promising preclinical efficacy against solid cancer cells. We designed, synthesized, and tested trifluoromethyl and methoxy MMe analogs (pCF3-MMe, mCF3-MMe, and pMeO-MMe) against multiple distinct human cancer cells. pCF3-MMe showed enhanced selectivity toward cancer cells compared to MMe, while retaining thesame signaling mechanism. Importantly, pCF3-MMe allowed quantitative monitoring of cellular accumulation via 19F-NMR invitro and invivo. Furthermore, adding trifluoromethyl groups to TPP+ reduced toxicity invivo while retaining anti-tumor efficacy, opening an avenue to de-risk these next-generation TPP+-conjugated compounds.

PD-1 Targeted Nanoparticles Inhibit Activated T Cells and Alleviate Autoimmunity via Suppression of Cellular Energy Metabolism Mediated by PKM2.

BackgroundEffector T cells, especially T helper 1 (Th1) cells and T helper 17 (Th17) cells, are involved in the pathogenesis of many autoimmune diseases such as uveitis. Under hyperactive immune conditions, these effector T cells pathologically maintain a high expression level of programmed cell death protein 1 (PD-1) receptors and distinctively engage aerobic glycolysis via cellular energy metabolism mediated by pyruvate kinase M2 (PKM2). Therefore, we proposed that the synergy of metabolic inhibition and receptor guidance might target and down-regulate these hyperactive effector T cells to achieve anti-immune effects.MethodsPD-1 antibody and TEPP-46 were integrated by polyethylene glycol (PEG) modified poly (lactic-co-glycolic acid) (PLGA) as a nanoplatform (TPP). Characteristics of TPP were basically detected. The biosafety of TPP was evaluated in vitro and in vivo. The targeting effect of TPP was detected by laser scanning confocal microscopy and flow cytometry (FCM). Interleukin-2 (IL-2)/interleukin-17A (IL-17A)/interferon-gamma (IFN-γ) producing cells were detected by FCM. Experimental autoimmune uveoretinitis (EAU) was induced in C57BL/6J mice as the inflammatory model.ResultsTPP had homogeneous distribution, good stability in vitro, and high biosafety in vitro and in vivo. Encapsulated TEPP-46 showed a sustained release profile with burst, steady and slow release periods. Early activation and proliferation of effector T cells was inhibited by TPP treatment in vitro. Th1 and Th17 cells were suppressed by TPP in vitro and in vivo. EAU was alleviated in mice by systemic administration of TPP.ConclusionThe novel nanoplatform TPP could suppress Th1 and Th17 cells and exhibited an anti-inflammatory effect on EAU, providing an alternative approach to ameliorate autoimmune diseases mediated by these cells.

A Stepwise Targeting Curcumin Derivative, Ser@TPP@CUR, for Acute Kidney Injury.

Based on the pathological mechanisms of acute kidney injury (AKI), a stepwise targeting curcumin derivative, Ser@TPP@CUR, was developed in this study. Ser@TPP@CUR can be specifically internalized by renal tubular epithelial cells via KIM-1 receptor-mediated endocytosis and then actively distributed in mitochondria under the effect of TPP, a mitochondrial targeting molecule. Both in vitro and in vivo results showed that Ser@TPP@CUR effectively ameliorated injured renal tubular epithelial cells and improved renal functions of AKI mice.

Polysaccharide extracted from Taraxacum platycarpum root exerts immunomodulatory activity via MAPK and NF-κB pathways in RAW264.7 cells

Ethnopharmacological relevanceTaraxacum platycarpum Dahlst. (Korean dandelion) is a medicinal herb used in traditional medicine in Korea to treat various disease such as furuncles, mammitis, hepatitis, jaundice. Moreover, a decoction prepared from T. platycarpum leaves and stems is an effective treatment for cancer, glycosuria, liver disease, pleurodynia, and stomach problems. Aim of the studyThe main objective of this work was to study the composition and structural properties of polysaccharides (TPP) from Taraxacum platycarpum Dahlst. root and investigate the immunostimulatory activity on RAW264.7 cells. Materials and methodsTPP was extracted from T. platycarpum using hot water extraction, ethanol precipitation method and its fractionated using DEAE-Sepharose fast flow column. The composition, molecular weight, and structural characterization of TPP and its fractions were evaluated by various techniques. Further, the immunostimulatory activity of polysaccharides was tested on murine macrophage cell line RAW264.7 by various in vitro assays. The structure effect of TPP on RAW264.7 cells was studied by the removal of sulfate (desulfation) and protein (deproteinization) contents from TPP. ResultsWe obtained three fractions namely TPP-1, TPP-2, and TPP-3 which mainly consisted of carbohydrates (75.55, 52.71, and 48.41%), sulfate (8.42, 15.19, and 27.67%), uronic acid (1.27, 6.56, and 4.39%), and protein (8.15, 24.85, and 9.73%). The average molecular weight of the fractions was 56.7, 108.2, and 132.3 × 103 g/mol, respectively. The polysaccharides activate the RAW264.7 cell to produce a significant amount of NO and upregulate the various mRNA expression by the activation of MAPK and NF-κB pathways via TLR4, TLR2, and CR3 receptors. The structurally modified deproteinated derivative (DP-TPP-2) more effectively decreases the NO production which means the protein content of TPP-2 mainly contributes to the RAW264.7 cells activation. The structure of DP-TPP-2 primarily consists of 1 → 2)-Galp, 1 → 6)-Glup, 1 → 2) - Rhap, and 1 → 5) - Arap glycosidic linkages. ConclusionsThe present study demonstrated that the polysaccharide isolated from T. platycarpum shows admirable immunostimulatory by the activation of MAPK and NF-κB pathways through TLR4, TLR2, and CR3 receptors. The protein content of polysaccharides mainly contributes to the RAW264.7 cells activation. Our study results could be useful for developing a new immunostimulant agent.

Photodynamic effect of TPP encapsulated in polystyrene nanoparticles toward multi-resistant pathogenic bacterial strains: AFM evaluation

Photodynamic inactivation (PDI) is a promising approach for the efficient killing of pathogenic microbes. In this study, the photodynamic effect of sulfonated polystyrene nanoparticles with encapsulated hydrophobic 5,10,15,20-tetraphenylporphyrin (TPP-NP) photosensitizers on Gram-positive (including multi-resistant) and Gram-negative bacterial strains was investigated. The cell viability was determined by the colony forming unit method. The results showed no dark cytotoxicity but high phototoxicity within the tested conditions. Gram-positive bacteria were more sensitive to TPP-NPs than Gram-negative bacteria. Atomic force microscopy was used to detect changes in the morphological properties of bacteria before and after the PDI treatment.

Inter-spike mitochondrial Ca2+ release enhances high frequency synaptic transmission.

Presynaptic mitochondria not only absorb but also release Ca2+ during high frequency stimulation (HFS) when presynaptic [Ca2+ ] is kept low (<500nm) by high cytosolic Ca2+ buffer or strong plasma membrane calcium clearance mechanisms under physiological external [Ca2+ ]. Mitochondrial Ca2+ release (MCR) does not alter the global presynaptic Ca2+ transients. MCR during HFS enhances short-term facilitation and steady state excitatory postsynaptic currents by increasing vesicular release probability. The intra-train MCR may provide residual calcium at interspike intervals, and thus support high frequency neurotransmission at central glutamatergic synapses. Emerging evidence indicates that mitochondrial Ca2+ buffering contributes to local regulation of synaptic transmission. It is unknown, however, whether mitochondrial Ca2+ release (MCR) occurs during high frequency synaptic transmission. Confirming the previous notion that 2μm tetraphenylphosphonium (TPP+ ) is a specific inhibitor of the mitochondrial Na+ /Ca2+ exchanger (mNCX), we studied the role of MCR via mNCX in short-term plasticity during high frequency stimulation (HFS) at the calyx of Held synapse of the rat. TPP+ reduced short-term facilitation (STF) and steady state excitatory postsynaptic currents during HFS at mature calyx synapses under physiological extracellular [Ca2+ ] ([Ca2+ ]o =1.2mm), but not at immature calyx or at 2mm [Ca2+ ]o . The inhibitory effects of TPP+ were stronger at synapses with morphologically complex calyces harbouring many swellings and at 32°C than at simple calyx synapses and at room temperature. These effects of TPP+ on STF were well correlated with those on the presynaptic mitochondrial [Ca2+ ] build-up during HFS. Mitochondrial [Ca2+ ] during HFS was increased by TPP+ at mature calyces under 1.2mm [Ca2+ ]o , and further enhanced at 32°C, but not under 2mm [Ca2+ ]o or at immature calyces. The close correlation of the effects of TPP+ on mitochondrial [Ca2+ ] with those on STF suggests that mNCX contributes to STF at the calyx of Held synapses. The intra-train MCR enhanced vesicular release probability without altering global presynaptic [Ca2+ ]. Our results suggest that MCR during HFS elevates local [Ca2+ ] near synaptic sites at interspike intervals to enhance STF and to support stable synaptic transmission under physiological [Ca2+ ]o .

Neuronal mitochondria-targeted therapy for Alzheimer’s disease by systemic delivery of resveratrol using dual-modified novel biomimetic nanosystems

Reactive oxygen species (ROS)-induced neuronal mitochondrial dysfunction is a key pathologic factor in sporadic Alzheimer’s disease (AD). Neuronal mitochondria have been proposed to be a promising therapeutic target for AD, especially for the failures of phase III clinical trials on conventional amyloid-β (Aβ) targeted therapy. However, the efficient intravenous delivery of therapeutic agents to neuronal mitochondria in the brain remains a major challenge due to the complicated physiological environment. Recently, biomaterials-based nanomedicine has been widely investigated for the treatment of AD. Herein, we devised a strategy for functional antioxidant delivery to neuronal mitochondria by loading antioxidants into red blood cell (RBC) membrane-coated nanostructured lipid carriers (NLC) bearing rabies virus glycoprotein (RVG29) and triphenylphosphine cation (TPP) molecules attached to the RBC membrane surface (RVG/TPP NPs@RBCm). With the advantage of suitable physicochemical properties of NLC and unique biological functions of the RBC membrane, RVG/TPP NPs@RBCm are stabilized and enabled sustained drug release, providing improved biocompatibility and long-term circulation. Under the synergistic effects of RVG29 and TPP, RVG/TPP NPs@RBCm can not only penetrate the blood–brain barrier (BBB) but also target neuron cells and further localize in the mitochondria. After encapsulating Resveratrol (RSV) as the model antioxidant, the data demonstrated that RVG/TPP-RSV NPs@RBCm can relieve AD symptoms by mitigating Aβ-related mitochondrial oxidative stress both in vitro and in vivo. The memory impairment in APP/PS1 mice is significantly improved following the systemic administration of RVG/TPP-RSV NPs@RBCm. In conclusion, intravenous neuronal mitochondria-targeted dual-modified novel biomimetic nanosystems are a promising therapeutic candidate for ROS-induced mitochondrial dysfunction in AD.

S-nitrosothiols loaded mini-sized Au@silica nanorod elicits collagen depletion and mitochondrial damage in solid tumor treatment.

To a large extent, the dense extracellular matrix (ECM), which tightly connects tumor cells to arm the tumor into an intractable fortress, significantly decreases the nanoparticles delivery efficacy and overall performance in cancer treatments. Therefore, it is necessary to transform the dense stroma of solid tumors to loose state, which could realize deep penetration of nanomedicine and enhance cancer treatment effects. Here, we fabricated a protein-free collagen nanosweeper, triphenylphosphonium bromide (TPP) coated and S-nitrosothiols loaded mini-sized Au@silica nanorod (Au@SiO2-SNO/PEG/TPP, GSNP-TPP), to clear the transport barriers of nanoparticles as well as elevate enhanced permeability and retention (EPR) effect, thus alleviating the diffusion resistance and realizing further penetration of nanoparticles.Methods: By modifying the Au@silica with thermo-sensitive S-nitrosothiols, the carrier could release the nitric oxide (NO) due to the surface overheat as well as perform photothermal therapy (PTT) under near-infrared (NIR) laser irradiation. The level of collagen depletion was observed via western blotting and immunofluorescent staining. In addition, the dual-imaging and antitumor efficiency of GSNP-TPPs were evaluated with the HeLa tumor-bearing mouse model.Results: On one hand, the released NO could deplete collagen by activating matrix metalloproteinases (MMPs) to break collagen fibers, thus loosening the dense ECM to enhance the cellular internalization. On the other hand, with the mitochondrial-targeted effect of TPP, the diffusible NO in tumor might rapidly interact with superoxide anion (O2Ÿ-) to produce highly toxic and powerful reactive nitrogen species (RNS) -- peroxynitrite (ONOO-), which resulted in mitochondrial damage to induce cell apoptosis. With the unique properties of mini-sized gold nanorods, the formulated nanoparticles exhibited good computed tomography (CT) and multi-spectral optoacoustic tomography (MSOT) imaging effects in precisely locating and monitoring tumor. Moreover, the antitumor efficacy of GSNP-TPPs + laser group was further confirmed by ex-vivo histological analysis of tumor tissue.Conclusion: This work points out a strategy to overcome the obstacle standing in nanoparticles penetration, and opens the door of further exploitation of NO-related theranostic systems.

Experimental and Electrochemical Research of an Efficient Corrosion and Scale Inhibitor

A novel corrosion and scale inhibitor (TPP) containing tobacco stem extract (TSE), polyepoxysuccinic acid (PESA), and polyaspartic acid (PASP) was obtained by the optimal proportion of the orthogonal test. The anticorrosion effect of TPP for carbon steel was researched by static weight-loss method, on-line simulated dynamic test, electrochemical measurement, and scanning electron microscopy (SEM). The results showed that TPP could protect carbon steel efficiently with a maximal corrosion inhibition rate of 85.7% and it was a mixed-type corrosion inhibitor, mainly exhibiting cathode suppression capacity. Simultaneously, the results of calcium carbonate deposition experiment indicated that the scale inhibition rate of TPP was up to 100%.

Can the Belt and Road Initiative Alleviate the Negative Impact of TPP on China

TPP is an important part of Asia-Pacific strategies of Obama Government. However, with the new President Trump taking office in the White House, the progress of TPP has met certain hindrance. Though Trump withdrew the United States from the TPP, it does not mean that TPP is completely aborted and traditional allies still negotiate on the signing of the Comprehensive Progressive Trans-Pacific Partnership （CPTPP）. How will the adjustment of TPP policy by the United States affect China? What economic benefits will the Belt and Road Initiative（BRI）that China put forward to counter potential impacts of TPP bring to the countries along the Belt and Road? Can BRI become an effective measure for China to counter TPP? Further, what kinds of differentiated industrial impacts will TPP and BRI bring to China and what kinds of challenges and opportunities? Analyses and discussions of these questions will be very helpful of enriching China’s strategies to counter TPP as well as accelerating the progress of BRI. With a Global Trade Analysis Project（GTAP）and the latest database GTAP 9.0, this paper quantitatively evaluates the economic effects of TPP and BRI in terms of the real GDP, the social welfare and the import and export trade. The study sets six policy scenarios centering on whether the U.S. should be back to TPP and how will China push forward BRI to selectively analyze benefits and losses of China under different macro-economic effects. The main conclusions of the paper are: （1）Judging from real GDP and residents’ welfare, China suffers from such strategy no matter the U.S. returns to TPP or not: in the scenario of GPTPP, the real GDP of China decreases 0.019% and the deterioration of residents’ welfare is USD4.111 billion; （2）Promotion of BRI is able to effectively alleviate the negative impacts of TPP on Chinese economy: when BRI and TPP both exist, the real GDP of China increases 0.055% and the improvement of residents’ welfare is USD11.465 billion; （3）From the perspective of unimpeded trade, promotion of BRI can stimulate outputs of energy-intensive industries of China, especially the textile and clothes industry, the steel and metal industry and the chemical industry, which is helpful to alleviate the problem of excess production capacities in the energy-intensive industries of China; （4）Implementation of BRI has strong negative impacts on South Korea, but if South Korea could participate in BRI, significance improvement can be realized in its economic growth and residents’ welfare. The marginal contributions of this paper can be elaborated from three aspects. First, this paper introduces both TPP and BRI to comparatively analyze international economic effects of different regional economic cooperation modes, which can provide a valuable technical reference for China to promote BRI in the context of TPP. Second, this paper provides a quantitative evaluation of the withdrawal of the U.S. from TPP, and the impact of the CPTPP on China is also discussed, which will be useful for China to adopt reasonable measures to cope with CPTPP. Third, the impacts of TPP on different countries or areas along the Belt and Road are quantitatively evaluated to reveal benefits and losses of these countries or areas under different TPP strategies, which is helpful of promoting those countries to participate in BRI to cope with the negative impacts of TPP.

Combined Effects of Bottom Ash and Expanded Polystyrene on Light-weight Concrete Properties

The benefits of using waste materials as a partial replacement for cement in high performance concrete are also discussed. This paper presents the combined effects of bottom ash TPP “Vung Ang” and expanded polystyrene aggregate on different the properties of light-weight concrete. Twenty different concrete mixtures with a water to cement ratio of 0.4 and superplasticizer to cement ratio of 0.015 were used. On the one hand, the EPS was partially replaced with (0 ÷ 40)% by volume of concrete mixture. On the other hand, the fine aggregate was replaced with (0 ÷ 30)% by mass of BA TPP “Vung Ang”. The engineering properties, including workability, density and compressive strength of light-weight concrete were investigated at different curing times. The level of decrease in the strength depends upon the replacement level of EPS and BA. Specifically, the concrete containing 40% EPS and 30% BA at 28 days of age decrease in average density and strength were 43.2% and 26.4%, respectively, in comparison with the control concrete.

Correction to: Multifunctional decoration of alpha-tocopheryl succinate-based NP for cancer treatment: effect of TPP and LTVSPWY peptide.

Correction to: Multifunctional decoration of alpha-tocopheryl succinate-based NP for cancer treatment: effect of TPP and LTVSPWY peptide.

Multifunctional decoration of alpha-tocopheryl succinate-based NP for cancer treatment: effect of TPP and LTVSPWY peptide.

Active targeting not only of a specific cell but also a specific organelle maximizes the therapeutic activity minimizing adverse side effects in healthy tissues. The present work describes the synthesis, characterization, and in vitro biological activity of active targeting nanoparticles(NP) for cancer therapy based on α-tocopheryl succinate (α-TOS), a well-known mitocan, that selectively induces apoptosis of cancer cells and proliferalting endothelial cells. Human epidermal growth factor receptor 2 (HER2) targeting peptide LTVSPWY (PEP) and triphenylphosphonium lipophilic cation (TPP) were conjugated to a previously optimized RAFT block copolymer that formed self-assembled NP of appropriate size for this application and low polydispersity by self-organized precipitation method. PEP and TPP were included in order to target not only HER2 positive cancer cells, but also the mitochondria of these cancer cells, respectively. The in vitro experiments demonstrated the faster incorporation of the active-targeting NP and the higher accumulation of TPP-bearing NP in the mitochondria of MDA-MB-453 HER2 positive cancer cells compared to non-decorated NP. Moreover, the encapsulation of additional α-TOS in the hydrophobic core of the NP was achieved with high efficiencies. The loaded NP presented higher cytotoxicity than unloaded NP but preserved their selectivity against cancer cells in a range of tested concentrations.

Ultrasound synergized with three-phase partitioning for extraction and separation of Corbicula fluminea polysaccharides and possible relevant mechanisms

Ultrasound and three-phase partitioning (USTPP) were combined to extract and separate polysaccharides (PS) efficiently from Corbicula fluminea crude extracts. The following optimum experimental conditions were established: 20% (w/v) ammonium sulfate concentration, 1:1 (v/v) t-butanol to crude extract ratio, 180W ultrasonic power, 40kHz frequency, 100% duty cycle, 10min irradiation time, and 35°C. The maximum extraction yield of PS obtained from USTPP was approximately 11.22%, which was higher than the maximum yields from conventional three-phase partitioning (TPP; 9.32%) and ultrasound extraction (USE; 6.05%). The extraction time for USTPP was significantly reduced to 10min from 30 and 60min for TPP and USE methods, respectively. The primary chemical structures of PS collected through the three extraction protocols were basically conserved. The synergistic effects of ultrasound and TPP on PS extraction were also determined. Results revealed that USTPP is an effective technique to extract and separate PS from C. fluminea potentially applied in food, cosmetics, and medicines.

The magnetoresistance effect in a conducting molecular crystal consisting of dicyano(phthalocyaninato)manganese(iii).

A conducting molecular crystal TPP[MnIII(Pc)(CN)2]2 (MnIII: d4, S = 1, TPP = tetraphenylphosphonium and Pc = phthalocyanine) was fabricated. In its crystal structure, the [MnIII(Pc)(CN)2] units formed a one-dimensional regular chain along the c-axis with an overlap integral value of 8.6 × 10-3. TPP[MnIII(Pc)(CN)2]2 showed a semiconducting behaviour that also has been observed for isostructural TPP[CoIII(Pc)(CN)2]2 (CoIII: d6, S = 0) and TPP[FeIII(Pc)(CN)2]2 (FeIII: d5, S = 1/2) whose ground states are charge-ordered states. In spite of the local magnetic moment of the MnIII ion (S = 1) at the centre of the Pc ligand, TPP[MnIII(Pc)(CN)2]2 exhibited an almost isotropic and small negative magnetoresistance (MR) effect (the MR ratio was -8.7% under 8 T at 10.7 K), contrarily to the anisotropic giant negative MR effect of TPP[FeIII(Pc)(CN)2]2. The isotropy was found to be due to a (dxz)1(dyz)1 electronic configuration, and the smaller MR effect was explained by a weaker antiferromagnetic interaction between MnIII ions than that between FeIII ions, as suggested by a Weiss temperature Θ of -3.1 K (|Jdd|/kB = 1.2 K).

Controlled growth of Au/Ni bimetallic nanocrystals with different nanostructures

Bimetallic nanomaterials are of great significance to both fundamental research and industrial applications. Their physicochemical performances are critically dependent on their architectures and electronic structures. Here, it was reported a controlled synthesis of Au/Ni bimetallic nanocrystals with different nanostructures, i.e., dumbbell, core@shell and alloyed nanostructures in a one-pot synthesis procedure. Detailed structural characterizations were conducted with the combination of transmission electron microscopy (TEM) and X-ray diffraction (XRD). Even there is a large lattice mismatch between Au and Ni, Au@Ni core@shell nanocrystals are obtained with the seeded growth method. The growth mechanism was deeply investigated. Triphenylphosphine is demonstrated to be an effective capping agent to modify the interfacial energy to form core@shell nanocrystals, and the higher temperature is proved to be a key role in obtaining alloyed nanocrystals. Au/Ni bimetallic nanocrystals with different architectures, i.e., dumbbell-like, core@shell and alloyed structures, were controlled synthesized through seeded growth method. Growth mechanism investigation suggests that the capping effect of TPP is beneficial for balancing the interfacial energy to support the growth of Ni shell on the surface of Au nanoparticles. The high temperature induces the migration of Au and Ni atoms to form alloyed nanocrystals.

A study of the economic impacts of the TPP on Korea: Armington and Melitz model

Purpose – The purpose of this paper is to measure the effects of TPP on Korean economy focussing on the changes in the number of firms and productivity. Design/methodology/approach – Following Melitz (2003) and Balistreri et al. (2011), the authors apply CGE simulation to five groups of 140 countries. Findings – The authors find that welfare increases in Korea to join the TPP regardless the size of the TPP through productivity improvement of participating firms and increases in the number of exporting firms, factor prices and outputs. Practical implications – This study helps tentative member countries of TPP decide to join. Originality/value – The effects of TPP to Korean economy is measured with Melitz model, which has not yet attempted before.