Factorial optimisation of the effects of extrusion temperature profile and polymer grade on as-spun aliphatic–aromatic co-polyester fibres III: mechanical properties

The effect of extrusion temperature profile in the melt‐spinning process of as‐spun linear aliphatic–aromatic co‐polyester (AAC) fibres upon their mechanical properties and process productivity was modelled by using factorial experimental designs. After the viscoelastic and morphology characteristics of the polymer were considered using Differential Scanning Calorimetry and Melt Flow Index (MFI), the rheological data were used to determine the enhanced melt‐spinning temperature of the six heating zones in the process. Tensile strength, elongation at break, modulus and fibre productivity (g/min) of the melt‐spinning process have been quantitatively assessed as responses to polymer grades and extrusion zone temperature. The optimisation of mechanical properties and productivity helps in understanding and controlling the most desired properties in the produced fibre. It has been noted that the die head temperature (spinning temperature), the polymer grade and their interaction are the most significant factors affecting the mechanical properties. Analysis of the fibre productivity shows that the polymer grade and its interaction with the die head temperature is significant in terms of influencing the output of the melt‐spinning process, which could be related to the polymer molecular weight and polymer structure. There is an interaction between polymer grade and feeding zone temperature which is related to the material supply action in the feeding zone. The friction between the screw and the material is affected by heating action, which affects the moisture content and the molten material rheology. By adjusting the extrusion temperature profile and selecting the more applicable spin‐able polymer grade through a statistical forecasting model, the combination of the cost related to material grade and processing cost controls the fibre production cost. The fibre made of low MFI grade has better structure and mechanical properties than that made of the higher MFI grade, and the former will be preferred for future work. With previous work related to the effects of extrusion temperature profile on the fibre structure, the present paper will help in developing the production process of biodegradable linear AAC fibres.     

New Flower-Shaped Lead(II) Coordination Polymer at the Nano Scale: Synthesis, Structural Characterization and DFT Calculations of [Pb(o-phen)(N3)2] n Containing the Pb-(μ1,1-N3)(μ1,3-N3) Motif

A new nano-flower lead(II) azido coordination polymer from the ligand, orthophenanthroline (o-phen), [Pb(o-phen)(μ_1,1-N₃)(μ_1,3-N₃)] _n (1), was synthesized by a sonochemical method. Compound 1 was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), elemental analyses and IR spectroscopy. Single crystalline material was obtained using a heat gradient applied to a solution of the reagents. The structure of 1 is a coordination polymer of lead(II) containing the Pb-(μ_1,1-N₃)(μ_1,3-N₃) motif, formed of one-dimensional chains. The structure of the 1 was optimized by density functional theory. Structural parameters and IR spectra for 1 are consistent with the crystal structure. Pure phase PbO nanoparticles were obtained by thermolysis of 1 with oleic acid as a surfactant at 180 and 200 °C an air. PbO nanoparticles were characterized by XRD and SEM.     

Solving the advection–diffusion equation on unstructured meshes with discontinuous/mixed finite elements and a local time stepping procedure

Explicit schemes are known to provide less numerical diffusion in solving the advection–diffusion equation, especially for advection‐dominated problems. Traditional explicit schemes use fixed time steps restricted by the global CFL condition in order to guarantee stability. This is known to slow down the computation especially for heterogeneous domains and/or unstructured meshes. To avoid this problem, local time stepping procedures where the time step is allowed to vary spatially in order to satisfy a local CFL condition have been developed. In this paper, a local time stepping approach is used with a numerical model based on discontinuous Galerkin/mixed finite element methods to solve the advection–diffusion equation. The developments are detailed for general unstructured triangular meshes. Numerical experiments are performed to show the efficiency of the numerical model for the simulation of (i) the transport of a solute on highly unstructured meshes and (ii) density‐driven flow, where the velocity field changes at each time step. The model gives stable results with significant reduction of the computational cost especially for the non‐linear problem. Moreover, numerical diffusion is also reduced for highly advective problems. Copyright © 2009 John Wiley & Sons, Ltd.     

Lu3+/Yb3+ and Lu3+/Er3+ co-doped antimony selenide nanomaterials: synthesis,characterization, and electrical,thermoelectrical, and optical properties

Lu³⁺/Yb³⁺ and Lu³⁺/Er³⁺ co-doped Sb₂Se₃ nanomaterials were synthesized by co-reduction method in hydrothermal condition. Powder X-ray diffraction patterns indicate that the Ln_xLn^′_xSb_2−2xSe₃ Ln: Lu³⁺/Yb³⁺ and Lu³⁺/Er³⁺ crystals (x = 0.00 − 0.04) are isostructural with Sb₂Se₃. The cell parameters were increased for compounds upon increasing the dopant content (x). Scanning electron microscopy and transmission electron microscopy images show that co-doping of Lu³⁺/Yb³⁺ ions in the lattice of Sb₂Se₃ produces nanorods, while that in Lu³⁺/Er³⁺ produces nanoparticles, respectively. The electrical conductivity of co-doped Sb₂Se₃ is higher than that of the pure Sb₂Se₃ and increases with temperature. By increasing the concentration of Ln³⁺ions, the absorption spectrum of Sb₂Se₃ shows red shifts and some intensity changes. In addition to the characteristic red emission peaks of Sb₂Se₃, emission spectra of co-doped materials show other emission bands originating from f-f transitions of the Yb³⁺ ions.     

Paclitaxel plus high-dose cyclophosphamide with G-CSF support in patients with relapsed and refractory aggressive non-Hodgkin's lymphoma

Based on the single-agent activity of both paclitaxel and cyclophosphamide in the treatment of non-Hodgkin's lymphoma (NHL), we conducted a phase II study to evaluate the efficacy of the combination of the two drugs in patients with refractory and relapsed aggressive NHL. All patients received 900 mg/m2 bolus of cyclophosphamide intravenously daily for 3 consecutive days with a concurrent infusion of 150 mg/m2 of paclitaxel over 72 h (50 mg/m2/d). 24 h after the completion of chemotherapy, patients received subcutaneous injections of 5 microg/kg of granulocyte-colony stimulating factor (G-CSF) daily until white cell count recovery. Treatment was repeated every 3 weeks. Patients who had at least a partial response (PR) after two courses continued to receive a maximum of four courses. Patients with responding disease were allowed to undergo high-dose chemotherapy followed by stem-cell/bone marrow transplantation if they were eligible. Of the 77 patients who were eligible for the study, 74 (96%) were evaluable for toxicity and treatment response. The overall response rate was 45% (95% CI 33-57%). Patients who received treatment after their disease relapsed from a complete response (CR) had an 81% response rate (38% CRs), whereas those with primary refractory disease had a 22% response rate. Toxicities of > grade 2 included alopecia (100%) and stomatitis (25%). Neutropenic fever of grade > 2 occurred after 18% of the courses, and platelet count of < or = 20 x 10(9)/l developed after 20% of the courses. Thus, the combination of paclitaxel plus high-dose cyclophosphamide is an effective new regimen in the treatment of refractory and relapsed NHL.     

Investigation of the Effects and Mechanisms of Anticancer Action of a Ru(II)-Arene Iminophosphorane Compound in Triple Negative Breast Cancer Cells

Triple negative breast cancer (TNBC) is one of the breast cancers with poorer prognosis and survival rates. TNBC has a disproportionally high incidence and mortality in women of African descent. We report on the evaluation of Ru-IM ( 1 ), a water-soluble organometallic ruthenium compound, in TNBC cell lines derived from patients of European (MDA-MB-231) and African (HCC-1806) ancestry (including IC₅₀ values, cellular and organelle uptake, cell death pathways, cell cycle, effects on migration, invasion, and angiogenesis, a preliminary proteomic analysis, and an NCI 60 cell-line panel screen). 1 was previously found highly efficacious in MDA-MB-231 cells and xenografts, with little systemic toxicity and preferential accumulation in the tumor. We observe a similar profile for this compound in the two cell lines studied, which includes high cytotoxicity, apoptotic behavior and potential antimetastatic and antiangiogenic properties. Cytokine M-CSF, involved in the PI3/AKT pathway, shows protein expression inhibition with exposure to 1 . We also demonstrate a p53 independent mechanism of action.     

An exponential SRGM with a bound on the number of failures

An exponential software reliability growth model (SRGM) incorporating a situation where more than one failure can be attributed to one fault/error has been proposed. Different model parameters have been estimated and an optimal release policy which minimizes the software cost, subject to achieving a given level of reliability, has been discussed. Finally, a numerical example illustrating the applicability of the model and a few practical situations where this model can be applied are also given.     

Observations on seminal vesicle dynamics in an in vivo rat model

PURPOSE: To gain understanding of the seminal vesicle as a muscular organ, seminal vesicle compliance and contractile properties were quantified with an in vivo, microsurgical rat model. MATERIALS AND METHODS: Microsurgical dissection was performed on anesthetized rats to enable simultaneous organ filling and monitoring of intraluminal pressures. The reliability and reproducibility of post-ganglionic hypogastric nerve-induced ipsilateral (4 rats) and bilateral (5 rats) seminal vesicle contractile responses were assessed during repeated nerve stimulation. Seminal vesicle resting compliance was assessed during a constant saline infusion (10 rats). Functional performance curves were obtained at fixed fill-volumes by measuring organ contraction after nerve stimulation (4 rats). RESULTS: A reproducible seminal vesicle contractile response was obtained with a nerve stimulation interval > 15 minutes. Bilateral seminal vesicle responses were observed with unilateral nerve stimulation. The resting organ compliance curve with saline filling exhibited a characteristic, triphasic response. Functional performance studies revealed that contractile performance improves as the fill-volume increases until the distensibility limit of the organ is reached. CONCLUSIONS: A reliable, in vivo, rat model of seminal vesicle organ compliance and contractility is described. The seminal vesicle is a highly contractile, compliant smooth muscular organ with dynamic properties analogous to that of the urinary bladder. This experimental system may allow for the investigation of pharmacologic and other physiological influences on in vivo organ activity.