Optimization of Ciprofloxacin Adsorption on Clinoptilolite-Based Adsorbents Using Response Surface Methodology

The adsorption of the antibiotic ciprofloxacin (CIP) from water solution by natural zeolite-clinoptilolite (CLI), magnetic clinoptilolite (MAG-CLI), and graphene oxide coated magnetic clinoptilolite (GO-MAG-CLI) was investigated. The novel approach of an environmentally friendly and cost-effective microwave-assisted method was applied for the magnetic composite synthesis. Detailed characterization of the prepared composites was achieved. In order to investigate the effect of the initial CIP concentration, pH, temperature, contact time, and type of adsorbent on the adsorption efficiency of CIP, and to obtain the optimal conditions for CIP removal, the response surface methodology central composite factorial design (RSM-CCF) was applied. The results obtained by the RSM-CCF showed that among the studied adsorbents, GO-MAG-CLI had the highest adsorption capacity for CIP, achieved for the initial concentration of 48.47 mg dm^-3 at a pH of 5 and 24.78 °C after 19.20 min of contact time. The adsorption kinetics studied for the initial CIP concentration range of 15-50 mg dm^-3 followed Lagergren's pseudo-second-order model, and the Langmuir isotherm was the most suitable one to describe the CIP adsorption onto GO-MAG-CLI.

Statistical Optimisation of Chemical Stability of Hybrid Microwave-Sintered Alumina Ceramics in Nitric Acid

The goal of this research is the statistical optimisation of the chemical stability of hybrid microwave-sintered alumina ceramics in nitric acid. The chemical stability of ceramic materials in corrosive media depends on many parameters, such as the chemical and phase composition of the ceramics, the properties of the aggressive medium (concentration, temperature, and pressure), and the exposure time. Therefore, the chemical stability of alumina ceramics in different aqueous nitric acid solution concentrations (0.50 mol dm^-3, 1.25 mol dm^-3, and 2.00 mol dm^-3), different exposure times (up to 10 days), as well as different temperatures (25, 40, and 55 °C), was investigated, modelled, and optimised. The chemical stability of high purity alumina ceramics (99.8345 wt.% of Al₂O₃) was determined by measuring the amount of eluted ions (Al³⁺, Ca²⁺, Fe³⁺, Mg²⁺, Na⁺, and Si⁴⁺) obtained by inductively coupled plasma atomic emission spectrometry. The changes in the density of alumina ceramics during the chemical stability monitoring were also determined. The Box-Behnken approach was employed to reach the optimum conditions for obtaining the highest possible chemical stability of alumina at a given temperature range, exposure time, and molar concentration of nitric acid. It was found that an increase in exposure time, temperature, and nitric acid concentration led to an increase in the elution of ions from hybrid microwave-sintered alumina. Higher amounts of eluted ions, Al³⁺ (14.805 µg cm^-2), Ca²⁺ (7.079 µg cm^-2), Fe³⁺ (0.361 µg cm^-2), Mg²⁺ (3.654 µg cm^-2), and Na⁺ ions (13.261 µg cm^-2), were obtained at 55 °C in the 2 mol dm^{- 3} nitric acid. The amount of eluted Si⁴⁺ ions is below the detection limit of inductively coupled plasma atomic emission spectrometry. The change in the alumina ceramic density during the corrosion test was negligible.

Industry 4.0 Readiness Calculation-Transitional Strategy Definition by Decision Support Systems

The digitization of the manufacturing industry, 10 years after the introduction of the Industry 4.0 concept, is still one of the most demanding tasks for the companies, especially for SMEs. As one of the biggest barriers in new business model implementation, the lack of strategy and workforce skills is frequently mentioned in the literature. The high level of investments it requires and the perception of high risks with unclear future benefits can be avoided with readiness factor calculation. This paper presents a novel model for readiness factor calculation, oriented to process planning and based on decision support systems. The model enables the definition of the optimal strategic plan for the digitization with the use of decision support systems (analytic hierarchy process) and through the use of statistical methods implemented within the model it minimizes the influence of human subjectivity and quantification of qualitative criteria. This innovative approach enables the understanding of the transition process to new technology-enabled business models, in this case oriented towards process planning. The useability and reliability of the model is proven in a case study of a metal machining company.

Personalised urethra pessaries prepared by material extrusion-based additive manufacturing

Material extrusion-based additive manufacturing, commonly referred to as 3D-printing, is regarded as the key technology to pave the way for personalised medical treatment. This study explores the technique's potential in customising vaginal inserts with complex structures, so-called urethra pessaries. A novel, flawlessly 3D-printable and biocompatible polyester-based thermoplastic elastomer serves as the feedstock. Next to the smart selection of the 3D-printing parameters cross-sectional diameter and infill to tailor the pessary's mechanical properties, we elaborate test methods accounting for its application-specific requirements for the first time. The key property, i.e. the force the pessary exerts on the urethra to relief symptoms of urinary incontinence, is reliably adjusted within a broad range, including that of the commercial injection-moulded silicone product. The pessaries do not change upon long-term exposure to vaginal fluid simulant and compression (in-vivo conditions), satisfying the needs of repeated pessary use. Importantly, the vast majority of the 3D-printed pessaries allows for self-insertion and self-removal without any induced pessary rupture. Summarising, 3D-printed pessaries are not only a reasonable alternative to the commercial products, but build the basis to effectively treat inhomogeneous patient groups. They make the simple but very effective pessary therapy finally accessible to every woman.

The impact of the applied technology on health and productivity in manual "picker-to-part" systems

BACKGROUND

Manual "picker-to-part" order picking takes place in a labour-intensive and time-consuming working environment where humans are the central actors and co-determine the effectiveness and efficiency of the process. Throughout Europe, work-related musculoskeletal disorders affect millions of workers, especially in the logistics sector, and cost employers billions of euros.

OBJECTIVE

This paper studies how order pickers relate the use of technology as well as their relationship with the logistics company to their well-being, health and productivity.

METHODS

To obtain data, a survey consisting of questions regarding work characteristics, health problems and the logistics company's relationship with employees was conducted in Poland, Slovenia and Croatia.

RESULTS

Workers who carry most items manually experience more health problems than cart and forklift users. The most common complaint is lower back pain - only 6% of order pickers (n = 221) never experienced it. The use of barcode or RFID scanner/terminal/smart phone correlates with more health problems than the use of other technologies. Participation in the selection of transport means or in training on health preservation can reduce the perceived health problems.

CONCLUSIONS

Workers' perception of the impact of the applied technology on health and productivity can differ from the impact that is calculated or measured. Through their relationship with employees, logistics companies can influence employees' perception of their health problems.

Refinement strategy for antivenom preparation of high yield and quality

Antivenoms from hyperimmune animal plasma are the only specific pharmaceuticals against snakebites. The improvement of downstream processing strategies is of great interest, not only in terms of purity profile, but also from yield-to-cost perspective and rational use of plasma of animal origin. We report on development of an efficient refinement strategy for F(ab')2-based antivenom preparation. Process design was driven by the imperative to keep the active principle constantly in solution as a precautionary measure to preserve stability of its conformation (precipitation of active principle or its adsorption to chromatographic stationary phase has been completely avoided). IgG was extracted from hyperimmune horse plasma by 2% (V/V) caprylic acid, depleted from traces of precipitating agent and digested by pepsin. Balance between incomplete IgG fraction breakdown, F(ab')2 over-digestion and loss of the active principle's protective efficacy was achieved by adjusting pepsin to substrate ratio at the value of 4:300 (w/w), setting pH to 3.2 and incubation period to 1.5 h. Final polishing was accomplished by a combination of diafiltration and flow-through chromatography. Developed manufacturing strategy gave 100% pure and aggregate-free F(ab')2 preparation, as shown by size-exclusion HPLC and confirmed by MS/MS. The overall yield of 75% or higher compares favorably to others so far reported. This optimised procedure looks also promising for large-scale production of therapeutic antivenoms, since high yield of the active drug and fulfillment of the regulatory demand considering purity was achieved. The recovery of the active substance was precisely determined in each purification step enabling accurate estimation of the process cost-effectiveness.

Optimisation of the Adhesion of Polypropylene-Based Materials during Extrusion-Based Additive Manufacturing

Polypropylene (PP) parts produced by means of extrusion-based additive manufacturing, also known as fused filament fabrication, are prone to detaching from the build platform due to their strong tendency to shrink and warp. Apart from incorporating high volume fractions of fillers, one approach to mitigate this issue is to improve the adhesion between the first deposited layer and the build platform. However, a major challenge for PP is the lack of adhesion on standard platform materials, as well as a high risk of welding on PP-based platform materials. This study reports the material selection of build platform alternatives based on contact angle measurements. The adhesion forces, investigated by shear-off measurements, between PP-based filaments and the most promising platform material, an ultra-high-molecular-weight polyethylene (UHMW-PE), were optimised by a thorough parametric study. Higher adhesion forces were measured by increasing the platform and extrusion temperatures, increasing the flow rate and decreasing the thickness of the first layer. Apart from changes in printer settings, an increased surface roughness of the UHMW-PE platform led to a sufficient, weld-free adhesion for large-area parts of PP-based filaments, due to improved wetting, mechanical interlockings, and an increased surface area between the two materials in contact.