S-Adenosyl-L-methionine ameliorates TNF��-induced insulin resistance in 3T3-L1 adipocytes

An association between inflammatory processes and the pathogenesis of insulin resistance has been increasingly suggested. The IκB kinase-β (IKK-β)/ nuclear factor-κB (NF-κB) pathway is a molecular mediator of insulin resistance. S-Adenosyl-L-methionine (SAM) has both antioxidative and anti-inflammatory properties. We investigated the effects of SAM on the glucose transport and insulin signaling impaired by the tumor necrosis factor α (TNFα) in 3T3-L1 adipocytes. SAM partially reversed the basal and insulin stimulated glucose transport, which was impaired by TNFα. The TNFα-induced suppression of the tyrosine phosphorylation of the insulin receptor substrate-1 (IRS-1) and Akt in 3T3-L1 adipocytes was also reversed by SAM. In addition, SAM significantly attenuated the TNFα-induced degradation of IκB-α and NF-κB activation. Interestingly, SAM directly inhibited the kinase activity of IKK-β in vitro. These results suggest that SAM can alleviate TNFα mediated-insulin resistance by inhibiting the IKK-β/NF-κB pathway and thus can have a beneficial role in the treatment of type 2 diabetes mellitus.     

Comparative evaluation of software for retention time alignment of gas chromatography/time-of-flight mass spectrometry-based metabonomic data

In chromatography-based metabonomic research, retention time (RT) alignment of chromatographic peaks poses a challenge for the accurate profiling of biomarkers. Although a number of RT alignment software has been reported, the performance of these software packages have not been comprehensively evaluated. This study aimed to evaluate the RT alignment accuracy of publicly available and commercial RT alignment software. Two gas chromatography/mass spectrometry (GC/MS) datasets acquired from a mixture of standard metabolites and human bladder cancer urine samples, were used to assess three publicly available software packages, MetAlign, MZmine and TagFinder, and two commercial applications comprising the Calibration feature and Statistical Compare of ChromaTOF software. The overall RT alignment accuracies in aligning standard compounds mixture were 93, 92, 74, 73 and 42% for Calibration feature, MZmine, MetAlign, Statistical Compare and TagFinder, respectively. Additionally, unique trends were observed for the individual software with regards to the different experimental conditions related to extent and direction of RT shifts. Conflicting performance was observed for human urine samples suggesting that RT misalignments still occurred despite the use of RT alignment software. While RT alignment remains an inevitable step in data preprocessing, metabonomic researchers are recommended to perform manual check on the RT alignment of important biomarkers as part of their validation process.     

Tree-level recursion relation and dual superconformal symmetry of the ABJM theory

We propose a recursion relation for tree-level scattering amplitudes in three-dimensional Chern-Simons-matter theories. The recursion relation involves a complex deformation of momenta which generalizes the BCFW-deformation used in higher dimensions. Using background field methods, we show that all tree-level superamplitudes of the ABJM theory vanish for large deformations, establishing the validity of the recursion formula. Furthermore, we use the recursion relation to compute six-point and eight-point component amplitudes and match them with independent computations based on Feynman diagrams or the Grassmannian integral formula. As an application of the recursion relation, we prove that all tree-level amplitudes of the ABJM theory have dual superconformal symmetry. Using generalized unitarity methods, we extend this symmetry to the cut-constructible parts of the loop amplitudes.     

Anisotropic Dirac fermions in a Bi square net of SrMnBi2

We report the observation of highly anisotropic Dirac fermions in a Bi square net of SrMnBi(2), based on a first-principles calculation, angle-resolved photoemission spectroscopy, and quantum oscillations for high-quality single crystals. We found that the Dirac dispersion is generally induced in the (SrBi)(+) layer containing a double-sized Bi square net. In contrast to the commonly observed isotropic Dirac cone, the Dirac cone in SrMnBi(2) is highly anisotropic with a large momentum-dependent disparity of Fermi velocities of ~8. These findings demonstrate that a Bi square net, a common building block of various layered pnictides, provides a new platform that hosts highly anisotropic Dirac fermions.     

Synthesis and characterization of TiO2/Ag/polymer ternary nanoparticles via surface-initiated atom transfer radical polymerization

We report on the novel ternary hybrid materials consisting of semiconductor (TiO₂), metal (Ag) and polymer (poly(oxyethylene methacrylate) (POEM)). First, a hydrophilic polymer, i.e. POEM, was grafted from TiO₂ nanoparticles via the surface-initiated atom transfer radical polymerization (ATRP) technique. These TiO₂-POEM brush nanoparticles were used to template the formation of Ag nanoparticles by introduction of a AgCF₃SO₃ precursor and a NaBH₄ aqueous solution for reduction process. Successful grafting of polymeric chains from the surface of TiO₂ nanoparticles and the in situ formation of Ag nanoparticles within the polymeric chains were confirmed using transmission electron microscopy (TEM), UV-vis spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). FT-IR spectroscopy also revealed the specific interaction of Ag nanoparticles with the CO groups of POEM brushes. This study presents a simple route for the in situ synthesis of both metal and polymer confined within the semiconductor, producing ternary hybrid inorganic-organic nanomaterials.     

Very large street routing problem with mixed transportation mode

Providers of logistic services in recent years are under a big pressure to lower their expenses. One way to accomplish this task is centralization of logistic activities. This creates a distribution centers with a large number of customers. The capacity or time of one delivery person is limited, but, at the same time, it usually serves many customers. This problem is often called a Street Routing Problem (SRP). This paper is a survey of aggregation heuristics that can be used for a solution of Very Large SRP (VLSRP). Performance of heuristics has been evaluated based on real data. This paper presents several approximations of length for a SRP with mixed transportation mode and compares them with published approximations used for Vehicle Routing Problem (VRP) or Traveling Salesman Problems (TSP). The method was tested in seven real world instances ranging from 11000 to 29000 customers. Several aggregation methods including two new are presented and compared for the creation of delivery districts. New measurements for the quality of aggregation are created and tested on real data with all discussed aggregation methods.     

Examples of entropy generating sequence

We introduce the notion of entropy generating sequence for infinite words and define its dimension when it exists. We construct an entropy generating sequence for each symbolic example constructed by Cassaigne such that the dimension of the sequence is the same as its topological entropy dimension. Hence the complexity can be measured via the dimension of an entropy generating sequence. Moreover, we construct a weakly mixing example with subexponential growth rate.     

Excimer laser processing of ZnO thin films prepared by the sol-gel process

ZnO thin films were prepared on soda-lime glass from a single spin-coating deposition of a sol-gel prepared with anhydrous zinc acetate [Zn(C₂H₃O₂)₂], monoethanolamine [H₂NC₂H₄OH] and isopropanol. The deposited films were dried at 50 and 300 °C. X-ray analysis showed that the films were amorphous. Laser annealing was performed using an excimer laser. The laser pulse repetition rate was 25 Hz with a pulse energy of 5.9 mJ, giving a fluence of 225 mJ cm⁻² on the ZnO film. Typically, five laser pulses per unit area of the film were used. After laser processing, the hexagonal wurtzite phase of zinc oxide was observed from X-ray diffraction pattern analysis. The thin films had a transparency of greater than 70% in the visible region. The optical band-gap energy was 3.454 eV. Scanning electron microscopy and profilometry analysis highlighted the change in morphology that occurred as a result of laser processing. This comparative study shows that our sol-gel processing route differs significantly from ZnO sol-gel films prepared by conventional furnace annealing which requires temperatures above 450 °C for the formation of crystalline ZnO.     

Preparation of Ag‐Embedded Polystyrene Nanospheres and Nanocapsules by Miniemulsion Polymerization

An isopropyl myristate (IPM) biocompatible oil and an IPM solution of dodecanethiol‐capped Ag nanoparticles (NPs, 4.5 nm) were used as hydrophobes to suppress the Ostwald ripening of monomer/hydrophobe miniemulsified droplets in a surfactant‐stabilized water phase. The formation of non‐IPM‐encapsulated nanospheres (48 nm) and IPM‐encapsulated nanocapsules (90 nm) were precisely controlled by using a water‐soluble and an oil‐soluble initiator, respectively, in the presence of a pure IPM as a hydrophobe in miniemulsion polymerization. Well‐defined PS nanospheres, on which surfaces were coated with Ag NPs (Ag/PS nanospheres, 65 nm), and nanocapsules encapsulating both NPs and IPM liquid phase (Ag‐IPM/PS nanocapsules, 115 nm) were made by replacing the hydrophobe from pure IPM with Ag/IPM solution. These nanostructures were characterized by transmission and scanning electron microscopes.