Investigation of modified SEBS‐based thermoplastic elastomers by temperature scanning stress relaxation measurements

Thermoplastic elastomers (TPEs) based on poly(styrene‐b‐ethylene/butylene‐b‐styrene) (SEBS), modified with poly(2,6‐dimethyl‐1,4‐phenylene ether) (PPE), were investigated by a new testing method. The development and characterization of TPEs with improved temperature and oil resistance is a current area of research to extend the applications of TPEs, especially in the automotive industry. Thermal scanning stress relaxation (TSSR) was used to investigate the relaxation behavior of compounds containing SEBS, blended with extender oil, various amounts of PPE and in some cases with a thermoplastic polymer. Polyamide 12 (PA12) or polypropylene (PP) were used as the thermoplastic component. TSSR measurements were applied to detect relaxation changes in the glass transition region of the polystyrene blocks mixed with PPE. It was shown that the glass transition temperature increased with addition of PPE to the compound up to a limit of approximately 150°C, which corresponded to a weight fraction of PPE in the polystyrene (PS)‐block of 0.5. The increased glass transition temperature lead to SEBS‐based thermoplastic elastomer compounds with improved upper service temperatures. Phase images obtained by atomic force microscopy showed that the addition of PPE results in an increase of hard phase dimension. The addition of a thermoplastic polymer improved the mechanical properties and temperature resistance, but naturally decreased the elasticity of the compounds. Compounds containing PA12 exhibited an improved oil resistance. POLYM. ENG. SCI., 45:1498–1507, 2005. © 2005 Society of Plastics Engineers     

Antiviral Effects of ABMA and DABMA against Influenza Virus In Vitro and In Vivo via Regulating the Endolysosomal Pathway and Autophagy

Influenza virus is an acute and highly contagious respiratory pathogen that causes great concern to public health and for which there is a need for extensive drug discovery. The small chemical compound ABMA and its analog DABMA, containing an adamantane or a dimethyl-adamantane group, respectively, have been demonstrated to inhibit multiple toxins (diphtheria toxin, Clostridium difficile toxin B, Clostridium sordellii lethal toxin) and viruses (Ebola, rabies virus, HSV-2) by acting on the host’s vesicle trafficking. Here, we showed that ABMA and DABMA have antiviral effects against both amantadine-sensitive influenza virus subtypes (H1N1 and H3N2), amantadine-resistant subtypes (H3N2), and influenza B virus with EC₅₀ values ranging from 2.83 to 7.36 µM (ABMA) and 1.82 to 6.73 µM (DABMA), respectively. ABMA and DABMA inhibited the replication of influenza virus genomic RNA and protein synthesis by interfering with the entry stage of the virus. Molecular docking evaluation together with activity against amantadine-resistant influenza virus strains suggested that ABMA and DABMA were not acting as M2 ion channel blockers. Subsequently, we found that early internalized H1N1 virions were retained in accumulated late endosome compartments after ABMA treatment. Additionally, ABMA disrupted the early stages of the H1N1 life cycle or viral RNA synthesis by interfering with autophagy. ABMA and DABMA protected mice from an intranasal H1N1 challenge with an improved survival rate of 67%. The present study suggests that ABMA and DABMA are potential antiviral leads for the development of a host-directed treatment against influenza virus infection.     

Heterolytic activation of hydrogen gas: New evidence for Spencer–Yu hypothesis!

Hydrogenolysis or deuterogenolysis of organolithium compounds is described for the first time under heterogeneous catalysis. This work establishes that the carbon–lithium bond can undergo a facile reduction reaction when catalyzed by palladium or platinum catalysts and provides strong evidence for the existence of Pd^δ−–H^δ+ species.     

Analyse et conception de filtre passe-bande en guide nervuré par l’approche variationnelle

A multimodal variational approach is presented for the characterization of various uni-axial discontinuities in homogeneous waveguide. A study is carried out on the ridged waveguide discontinuities, and the results have been used for the optimized design of a bandpass filter. The introduction of the notion of coupled and uncoupled modes allows reduction of the order of the matrices handled in the numerical calculation and facilitates the use of the optimization process. The theoretical results are in good agreement with measured data.     

First lessons of the Toulouse ammonium nitrate disaster, 21st September 2001, AZF plant, France

A terrible explosion of ammonium nitrate, killing 30 people, occurred on 21st September 2001, in Toulouse, in AZF plant belonging to Grande Paroisse Company, TotalFinaElf Group. The manufactured chemicals in the plant were mainly ammonium nitrate, ammonium nitrate-based fertilisers and other chemicals including chlorinated compounds. The origins of the accident haven't found yet an agreement among investigators (company, justice). The aim of this paper is to provide abroad an overview of some lessons learnt on that accident, from many perspectives, following the national debates and parliamentary enquiry as well as the various technical accident investigations.     

Approximation of a Direction of Nd in Bounded Coordinates

In this paper, we address the following problem: a direction in R ^d is given by a vector with large integral coordinates and we have to find a vector with bounded integral coordinates which realizes a good approximation of this direction. We present a short algorithm that efficiently computes an optimal approximation with respect to the distance to the direction. We then compare experimental results with those of a straightforward rounding algorithm with respect to the distance to the direction and to the angle with it.     

Liver Transplantation for Colorectal Liver Metastases: Current Management and Future Perspectives

Patients with nonresectable liver metastases from colorectal cancer have few therapeutic options and a dismal prognosis. Although liver transplantation for this indication has historically a poor reputation, recent advances in the field of chemotherapy and immunosuppression have paved the way to revisit the concept. New data have shown promising results that need to be validated in several ongoing clinical trials. Since liver grafts represent a scarce resource, several new tools are being explored to expand the donor pool for this indication. The purpose of this review is to present all current available data and perspectives about liver transplantation for nonresectable liver metastases from colorectal cancer.     

Oxidative stability of water/oil mixtures as influenced by the addition of free Cu or Cu–alginate gel beads

The formation of Cu–alginate complexes and the impact of free or bound copper on the oxidative stability of model water/oil mixtures containing edible sunflower or corn oil were examined. Equilibrium dialysis showed that copper binding capacity of alginate increased proportionally with copper concentration and the binding was rapid. The results indicated that 25 mM CuCl₂ was necessary in obtaining beads of spherical shape and adequate mechanical strength (0.45 N at 80% compression) to avoid rupture during mixing, whereas lower CuCl₂ concentrations resulted in weak gel beads (0.34 N) of irregular shape. When Cu–alginate beads were dispersed in the aqueous phase to give 0.5 mM copper, the peroxide value of water/corn oil mixtures was 3.7 mEq peroxide/kg oil after 7 days. Corn oil-containing mixtures with 0.5 mM free Cu²⁺ in the aqueous phase had a peroxide value ∼3 times higher (P < 0.001) after the same storage time. However, copper binding by alginate did not significantly reduce the peroxide values of the water/sunflower oil mixtures. Results indicated that the binding of pro-oxidant minerals, such as copper, in alginate beads can reduce the levels of oxidation in water/oil mixtures.     

Effects of hole and electron trapping on organic field-effect transistor transfer characteristic

Routine organic field-effect transistor measurements are performed at negative and positive gate voltages leading to the occurrence of both hole and electron trapping. Despite this fact, the big majority of studies have focused either on hole trapping or on electron trapping but not on both at the same time. This paper presents the influences of trapped electron concentration n_trap and trapped hole concentration p_trap on the transfer characteristic (TC) features: onset voltage, hysteresis and transconductance, i.e. apparent mobility. Some effects are common to both charge types: (1) hysteresis is due to a combination of lower detrapping rate than sweep rate for n_trap and p_trap, (2) the transconductance is decreased by the super-linear V_G dependence of p_trap and by n_trap detrapping. One effect is opposite to both charge types: p_trap (n_trap) shifts the onset voltage towards negative (positive) value. We consider that the knowledge of trap-induced effects from both charge types is useful for correctly interpreting and understanding TCs.