Wall effects for the pressure drop in fixed beds

A very simple model is presented for the effect of the container wall on the pressure drop in a fluid flowing through a bed of spheres. It is based on the application of the Ergun equation to the bulk region of the bed, unaffected by the wall. Pressure loss predictions are found to correspond well to the opposing trends reported in the literature for the viscous- and inertial-flow regimes.     

Migration of α-tocopherol and resveratrol from poly(L-lactic acid)/starch blends films into ethanol

Poly(L-lactic acid) (PLLA)/starch blends with various concentrations of two natural antioxidants, α-tocopherol (α-TOC) and resveratrol, were fabricated by a melt blending and compression molding processes. The effects of the two antioxidants on the optical (color), thermal and mechanical properties of PLLA/starch blends with antioxidants were assessed. PLLA/starch blend films with α-TOC and resveratrol showed a yellowish color influenced by the combined effect of white starch and the brown color of the antioxidants. The glass transition and melting temperatures were significantly reduced with the addition of antioxidants while enhanced thermal stability was observed, which could be a benefit and important for processing and production. The enhanced mechanical properties could be attributed to not only a compatibilization effect based on the chemical linkage between PLLA and starch chains, but also restriction of the chain mobility by antioxidants. The release of resveratrol from PLLA and PLLA/starch blend films into ethanol followed Fickian behavior. The D values of α-TOC were in the range of 0.47–3.95 × 10⁻¹¹ cm² s⁻¹ for PLLA films and 0.70–6.83 × 10⁻¹¹ cm² s⁻¹ for PLLA/starch blend films at 13 °C, 5.67–13.0 × 10⁻¹¹ cm² s⁻¹ for PLLA films and 4.10–24.2 × 10⁻¹¹ cm² s⁻¹ for PLLA/starch blend films at 23 °C, and 89.0–118.0 × 10⁻¹¹ cm² s⁻¹ for PLLA films and 123–282 × 10⁻¹¹ cm² s⁻¹ for PLLA/starch blend films at 43 °C. The D values of resveratrol were in the range of 0.073–0.54 × 10⁻¹⁰ cm² s⁻¹ for PLLA films and 1.42–6.93 × 10⁻¹⁰ cm² s⁻¹ for PLLA/starch blend films at 13 °C, 0.90–3.44 × 10⁻¹⁰ cm² s⁻¹ for PLLA films and 4.16–22.3 × 10⁻¹⁰ cm² s⁻¹ for PLLA/starch blend films at 23 °C, and 24.8–74.1 × 10⁻¹⁰ cm² s⁻¹ for PLLA films and 40.1–309 × 10⁻¹⁰ cm² s⁻¹ for PLLA/starch blend films at 43 °C.     

Identification of genes regulated by interleukin-1beta in human endometrial stromal cells

Interleukin-1beta (IL-1b) is an important immune regulatory factor that in human endometrium plays a role in both menstruation and implantation in the event of pregnancy. It promotes inflammatory-like processes and also stimulates tissue remodelling. We present a cDNA microarray study documenting the major effects of IL-1beta on gene expression in stromal cells from human endometrium. Endometrial stromal cells from five normal healthy women at the mid secretory phase were cultured with or without IL-1beta at 50 and 500 pg/ml for 48 h. cDNA microarrays were used to compare the levels of gene expression in total RNA isolated from cells stimulated with IL-1beta. These cDNA arrays were produced containing 15 164 sequence-verified clones, which included genes known to be important in angiogenesis, immune modulators, apoptosis, cell signalling, extra-cellular matrix (ECM) remodelling and cell cycle regulation. Genes which were regulated by IL-1beta were identified by analysis of the microarray data using the Significance Analysis of Microarrays software package. Upregulated (n = 23) and downregulated (n = 6) different genes were observed, which changed at least 3-fold, at a false discovery rate of less than 2% (P < 0.02). Our results have identified genes regulated by IL-1beta, which are involved in leukocyte recruitment, ECM remodelling and other cellular functions. Changes in three genes, IL-8, colony-stimulating factor 2 and aldoketo reductase family 1 member 1, which were upregulated by IL-1beta, were verified using real-time PCR. Novel functions regulated by IL-1beta in endometrium, including genes involved in free radical protection, and fatty acid metabolism were also identified. These results also provide new insights into the role of IL-1beta in disorders of the endometrium, especially in implantation-related infertility and endometriosis, in which this cytokine plays a major role.     

The view from abroad on a parade of choices: Alternative processes to the ‘traditional’ alternative,arbitration

Mauro Rubino‐Sammartano , of Milan, Italy, discusses European alternatives to arbitration that have proven effective in resolving commercial disputes in a variety of forums.     

Harmonics and transient overvoltages due to capacitor switching

This work presents a study of the steady-state and transient effects of power factor correction capacitors on the utility and on the customer. In the presence of harmonic-producing loads, capacitors used for power factor correction can cause parallel or series resonance problems which tend to increase the total harmonic distortion (THD) of the voltage and current waveforms. The cases studied in this work considers the addition of a power factor correction capacitor, in the presence of downstream harmonic loads and at the harmonic load site. In both cases the resonance created by the addition of the capacitor caused the harmonic distortion of the voltage and current waveforms to increase. Another problem is transient overvoltages created by switching the capacitor. A case study is reported where the operation of a semiconductor controlled motor drive is effected by transient overvoltages     

OPERA: a novel method to reduce ghost and aliasing artifacts

Objective

A method for Orthogonal Phase Encoding Reduction of Artifact (OPERA) was developed and tested.

Materials and methods

Because the position of ghosts and aliasing artifacts is predictable along columns or rows, OPERA combines the intensity values of two images acquired using the same parameters, but with swapped phase-encoding directions, to correct the artifacts. Simulations and phantom experiments were conducted to define the efficacy, robustness, and reproducibility. Clinical validation was performed on a total of 1003 images by comparing the OPERA-corrected images and the corresponding image standard in terms of Signal-to-Noise Ratio (SNR) and Contrast-to-Noise Ratio (CNR). The method efficacy was also rated using a Likert-type scale response by two experienced independent radiologists using a single-blinded procedure.

Results

Simulations and phantom experiments demonstrated the robustness and effectiveness of OPERA in reducing artifacts strength. OPERA application did not significantly change the SNR [+?4.16%; inter-quartile range (IQR): 2.72–5.01%] and CNR (+?4.30%; IQR: 2.86–6.04%) values. The two radiologists observed a total of 893 original images with artifacts (89.03% of the total images), a reduction in the perceived artifacts of 82.0% and 83.9% (p?<?0.0001), and an improvement in the perceived SNR (82.8% and 88.5%; K?=?0.714) and perceived CNR (86.9–88.9%; K?=?0.722).

Discussion

The study demonstrated that OPERA reduces MR artifacts and improves the perceived image quality.

     

Congenital diarrheal disorders: an updated diagnostic approach

Congenital diarrheal disorders (CDDs) are a group of inherited enteropathies with a typical onset early in the life. Infants with these disorders have frequently chronic diarrhea of sufficient severity to require parenteral nutrition. For most CDDs the disease-gene is known and molecular analysis may contribute to an unequivocal diagnosis. We review CDDs on the basis of the genetic defect, focusing on the significant contribution of molecular analysis in the complex, multistep diagnostic work-up.     

Functionalized polysiloxane coatings on hot‐rolled and high‐strength Fe 430 B steel: Analysis of mechanical response and resistance to chemicals

Hybrid organic‐inorganic coatings can be extremely beneficial to improve the performance of steel substrates as their outstanding adhesion strength, scratch resistance, and chemical endurance. However, the design and manufacture of the appropriate coating systems on the different metal alloys can be troublesome. Defective coatings can cause the deterioration of their performance, especially the resistance to aggressive chemicals. In this work, the deposition of functionalized methyl phenyl polysiloxane resins on hot rolled and high strength Fe 430 B steel substrates with and without an intermediate layer of a hybrid organic‐inorganic grafting polymer (vinyltriethoxysilane) is comparatively evaluated. Visual appearance, scratch and wear resistance of the coatings as well as their attitude to act as chemical proof barriers are investigated. Proper functionalization of methyl phenyl polysiloxane resins with hydroxyl and alkoxy groups can lead to coatings that are well adhered to the underlying substrates, thus exploiting all the performance they were designed for. In this case, the use of an organo‐silane interlayer can further increment the final properties of the overall coating systems. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40624.     

The Discovery of Potent Nonstructural Protein 5A (NS5A) Inhibitors with a Unique Resistance Profile—Part 2

In ongoing studies towards novel hepatitis C virus (HCV) therapeutics, inhibitors of nonstructural protein 5A (NS5A) were evaluated. Specifically, starting from previously reported lead compounds, peripheral substitution patterns of a series of biaryl‐linked pyrrolidine NS5A replication complex inhibitors were probed and structure–activity relationships were elucidated. Using molecular modelling and a supercritical fluid chromatographic (SFC) technique, intramolecular H‐bonding and peripheral functional group topology were evaluated as key determinants of activity and membrane permeability. The novel compounds exhibited retained potency as compared with the lead compounds, and also showed promising results against a panel of resistance viruses. Together, the results of the study take us a step closer towards understanding the potency of daclatasvir, a clinical candidate upon which the compounds were based, and to designing improved analogues as second‐generation antiviral agents targeting NS5A.     

Environmentally friendly wooden-based coatings for thermal insulation: Design,manufacturing and performances

The design of an innovative protective and thermal insulating coating is investigated. The coating is composed of two superimposed layers; the innermost layer consists of dried beech dust dispersed in a diluted polyurethane binder, while the outermost layer is a conventional decorative hybrid epoxy-polyester powder coating. Each layer was sprayed on a metal substrate and baked at moderate temperature to consolidate the coatings and establish their full properties. The morphological features, mechanical response, protective and thermal insulating performance of the coatings were experimentally analysed by varying their structure and dried beech dust concentration in the binder. These coatings exhibit high potential in terms of thermal insulation and also show remarkable behaviour in terms of visual appearance, adhesion to the substrate and long lasting.