A systematic investigation of the overall rate coefficient in the Wheeler-Jonas equation for adsorption on dry activated carbons

Modelling of the adsorption rate coefficient, k_v of the Wheeler-Jonas equation for estimating the service life of packed carbon beds, is addressed. Current methods for extracting k_v from experimental breakthrough data include approaches that introduce easily propagated errors. The weaknesses of these approaches are analyzed, and a calculation based on multiple points on the breakthrough curve is suggested. Experimental breakthrough data for a representative set of volatile organic compounds (VOCs) has been measured. A systematic investigation of factors influencing k_v, including adsorbate and carbon properties, adsorbate inlet concentration and flow velocity is performed. It is found that flow velocity and carbon particle size have the largest influence, followed by adsorbate properties related to the adsorption capacity. A simple linear empirical model for k_v, including air flow velocity, carbon particle size, and dielectric constant of the adsorbate, is presented. The model is based on the breakthrough range up to 20% of the inlet concentration, for which k_v is shown to be almost constant. The range of the model covers breathing rates valid for a respirator at different work loads. The model can be used to estimate the adsorption rate coefficient for specific carbon particle sizes and various VOCs present in workplace environments.     

Graft copolymerization of glycidylmethacrylate onto modified nylon‐6 fibers

The graft copolymerization of glycidylmethacrylate (GMA) onto modified nylon‐6 fibers containing polydiallyldimethylammonium chloride (PDADMAC) groups in the presence of (Cu ²⁺–K₂S₂O₈) as a redox initiating system was carried out, with very high extent and almost without homopolymer formation. The mechanism of the graft polymerization induced by this system was suggested. The rate of grafting was determined by varying the monomer, K₂S₂O₈, and cupric ion concentrations as well as the amount of PDADMAC. The kinetic investigation revealed that the rate of grafting (Rp) of GMA onto modified nylon‐6 fibers is proportional to [GMA]^1.83, [CuSO₄·5H₂O]^0.46, [PDADMAC]^0.4, and [K₂S₂O₈]^1.43. The overall activation energy was 134.7 kJ/mol. The fine structure and thermal properties of the grafted nylon‐6 fibers were investigated. investigated. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 613–618, 2006     

Cell Fusion of Mesenchymal Stem/Stromal Cells and Breast Cancer Cells Leads to the Formation of Hybrid Cells Exhibiting Diverse and Individual (Stem Cell) Characteristics

Cancer is one of the most common diseases worldwide, and treatment bears many challenges such as drug and radioresistance and formation of metastases. These difficulties are due to tumor heterogeneity, which has many origins. One may be cell fusion, a process that is relevant in both physiological (e.g., wound healing) and pathophysiological (cancer and viral infection) processes. In this study, we examined if cell fusion between mesenchymal stem/stromal cells (MSCs) and breast cancer (BC) cells occurs and if newly generated hybrid cells may exhibit cancer stem/initiating cell (CS/IC) characteristics. Therefore, several methods such as mammosphere assay, AldeRed assay, flow cytometry (CD24, CD44, CD104) and Western blot analysis (of epithelial to mesenchymal transition markers such as SNAIL, SLUG and Twist) were applied. In short, four different hybrid clones, verified by short tandem repeat (STR) analysis, were analyzed; each expressed an individual phenotype that seemed not to be explicitly related to either a more stem cell or cancer cell phenotype. These results show that cancer cells and MSCs are able to fuse spontaneously in vitro, thereby giving rise to hybrid cells with new properties, which likely indicate that cell fusion may be a trigger for tumor heterogeneity.     

The effects of cultural dimension on ICT innovation: Empirical analysis of mobile phone services

ICT Innovation is one of the major forces for socioeconomic development. It is the key element to spur growth of the economy of a nation. Several studies have shown that culture is a crucial determinant of innovations. This study examines the effect of socio-cultural factors on ICT innovation with specific focus on the mobile banking services. Research was conducted on 220 respondents from sampled population in South Africa. The questionnaire used in this study was developed based on previous studies that have proven validity. The findings indicate that culture is an appropriate concept to describe how innovation in information and communication technology can be influenced by human behavior.     

Ultrafiltration of kraft cooking liquors from a continuous cooking process

Two cooking liquors and a black liquor were fractionated by ultrafiltration. The liquors were withdrawn from different stages in a kraft pulp mill employing continuous digestion. The ultrafiltration was performed at 90°C with two ceramic membranes with cut-offs of 5 kDa and 15 kDa. Only small differences in membrane performance were observed when concentrating the three liquors to 90% volume reduction. The average flux was 55 l/m² h for the 5 kDa membrane and about 115 l/m² h for the 15 kDa membrane. The concentration of lignin was on average 230 and 155 g/L in the retentate from the 5 kDa and 15 kDa cut-off membranes. The ash content was reduced from 37–40 g/g total dry solids to 20–30 g/g after ultrafiltration.     

Musculoskeletal, visual and psychosocial stress in VDU operators before and after multidisciplinary ergonomic interventions. A 6 years prospective study—Part II

A prospective epidemiological field study covering a 2 years period has earlier been published (Appl. Ergon. (1998) 29(5) 335). The study has a parallel group design with two intervention groups (T and S) and one control group (C) of Visual Display Unit (VDU) operators. The present paper covers the period from 2 to 6 years of the study. After 3.5 years, the C group got the same intervention in terms of new lighting system, new workplaces and at last an optometric examination and corrections if needed. The C group reported a significant reduction in visual discomfort after interventions while the two groups (T and S) continued to report significant reduction of visual discomfort after 6 years. By supporting the forearm on the table top, the C group reported significant reduction of shoulder and neck pain while the T group reported significant reduction in shoulder and back pain after 6 years. Organizational and psychosocial factors at work and outside work did not show any significant changes during the study period.     

Effect of commercial breakfast fibre cereals compared with corn flakes on postprandial blood glucose,gastric emptying and satiety in healthy subjects: a randomized blinded crossover trial

Background  

Dietary fibre food intake is related to a reduced risk of developing diabetes mellitus. However, the mechanism of this effect is still not clear. The aim of this study was to evaluate the effect of commercial fibre cereals on the rate of gastric emptying, postprandial glucose response and satiety in healthy subjects.     

Extraction with Water-in-Carbon Dioxide Microemulsions: A Case Study on Steviol Glycosides

This work explores the use of water-in-supercritical carbon dioxide (scCO₂) microemulsions for the extraction of polar metabolites from plants. Stevia rebaudiana Bertoni leaves and polyethylene glycol trimethylnonyl ether (TMN) surfactants were selected for a case study. A CO₂-water-TMN 10 mixture at 35 °C and 30.0 MPa extracted 7 mg target analyte/g dry leaves. The extraction was proven to occur due to a water-surfactant liquid solution rather than a water-in-CO₂ microemulsion. Using a modified extraction setup, the microemulsion was created prior to extraction. TMN 6 was able to dissolve enough water in CO₂ to extract steviol glycosides, in detectable but very small amounts.