Functionalized-radiolabeled hydroxyapatite/tenorite nanoparticles as theranostic agents for osteosarcoma

Hydroxyapatite (HA) nanoparticles (NPs) doped with different radioisotopes for use as theranostic systems play an important role in scientific research nowadays due to their ability to simultaneously act in the treatment and diagnosis of various types of cancers. In this work, we describe the synthesis and characterization of a hydroxyapatite/tenorite nanocomposite functionalized with folic acid, representing a nanotheranostic material with potential for application as an agent in positron emission tomography imaging systems and to act specifically in the treatment and diagnosis of osteosarcoma. ⁶⁴Cu and ³²P were produced by nuclear activation in the TRIGA reactor at CDTN. The obtained samples were characterized by XRD with Rietveld refinement, XAFS, SEM, BET, TGA, FTIR, CHN, ICP-AES, XPS and gamma spectroscopy. We investigated how CuO grows in HA NPs, the stability of the interactions between CuO and HA constituents and the interactions between folic acid and the surface of the HA NPs. The results indicate the formation of a second phase (tenorite) besides hydroxyapatite, and that the interactions between the two phases are stable, resulting in a nanocomposite. Furthermore, the activation of ⁶⁴Cu and ³²P inside the HA matrix, through the exposition to a neutron flux, produces a theranostic material of interest for biological tests.     

Effect of the sintering temperature on microstructure and properties of Al2O3–Cu–Ni hybrid composites obtained by PPS

In the present research, the influence of sintering temperature on the microstructure and properties of Al₂O₃–Cu–Ni hybrid composites prepared by the Pulse Plasma Sintering (PPS) technique were described. In this research, three temperatures have been selected: 1250°C, 1300°C, and 1350°C. SEM observations were carried out to determine the distribution of the metallic phase in the composite depending on the sintering temperature. The conducted experiments and microscopic observations enabled a better understanding of the phenomena occurring between the ceramic matrix and metallic phase in the obtained materials. The mechanical properties like a hardness and fracture toughness were measured. The technology applied allowed us to obtain ceramic-metal composites with a homogeneous microstructure. It was found that the sintering temperature influences the selected physical and mechanical properties of the composites produced. It was found that samples produced at 1300°C are characterized by the highest relative density and the mechanical properties.     

Arduino-based slider setup for gas–liquid mass transfer investigations: Experiments and CFD simulations

The implementation of traditional sensors is a drawback when investigating mass transfer phenomena within microstructured devices, since they disturb the flow and reactor characteristics. An Arduino based slider setup is developed, which is equipped with a computer-vision system to track gas–liquid slug flow. This setup is combined with an optical analytical method allowing to compare experimental results against CFD simulations and investigate the entire lifetime of a single liquid slug with high spatial and temporal resolution. Volumetric mass transfer coefficients are measured and compared with data from literature and the mass transfer contribution of the liquid film is discussed.     

Sensitivity Analysis as a Tool for Estimating Numerical Modeling Results

Modeling of real physical processes by numerical methods is highly time-consuming and requires significant computational capacity. In some cases, tens or even hundreds of hours of high-power computing are needed to virtually model a real process that lasts one second. Processes that take many hours, such as drying, pose an even greater challenge. This problem can be solved in two ways: by using faster computers (such as computing clusters) or by significantly simplifying the modeled process (its geometry, physical phenomena, or the impact of individual factors). For this reason, all methods which speed up or minimize the number of simulations required to achieve the research objective should be analyzed. This article focuses on the latter approach, and it proposes a simple method for predicting the responses of a numerical model (values of any output parameter) to changes in input values (values of any input parameter). This method requires a base model, such as a numerical model which is qualitatively and quantitatively consistent with experimental observations, and a sensitivity analysis. This article discusses the mathematical and logical premises for the discussed model, and it proposes two methods for predicting numerical simulation results. Those methods are illustrated with examples which analyze the behavior of the Eulerian Multiphase Model and describe phase interactions based on Gidaspow's approach. The discussed example relies on data from a series of articles published by the authors in Drying Technology. This article was inspired by the observations made during a time-consuming process of modeling a spouted bed grain dryer, which was described in the above publications. The objective of this study was to discuss the advantages and possibilities created by sensitivity analyses of numerical models and to encourage their practical application.     

Single‐lumen tunneled catheter: An old but useful option

We report a case of long‐term uneventful catheter use in a patient with previous recurrent vascular access dysfunction and infection. A single‐lumen tunneled catheter was inserted into the left internal jugular vein after a failed attempt of dual‐lumen permanent catheter placement. The follow‐up since device implantation has exceeded 5 years without any complications related to vascular access.     

Creation of arteriovenous fistulae for hemodialysis in octogenarians

Elderly patients, defined as octogenarians and nonagenarians, are an increasing population entering renal replacement therapy. Advanced age appears as an exclusive factor negatively influencing dialysis practice. Elderly patients are referred late for the initiation of hemodialysis and more likely are offered catheters rather than arteriovenous fistulae (AVF), which increase mortality and negatively affect quality of life. We present our approach to the creation of vascular access for hemodialysis in this demanding population. In 2006–2012, 39 patients aged 85.9 ± 2.05 with end‐stage renal disease, mainly resulting from ischemic nephropathy, were admitted to the Department of Nephrology to establish permanent vascular access for hemodialysis: preferably AVF. Temporary dialysis catheters were implanted in uremic emergency to bridge the time to fistula creation/maturation. AVF was attempted in 87.2% of the patients. Primary AVF function was achieved in 54% of the patients. Cumulative proportional survival of AVF at months 12 and 24 was 81.5%. Ninety‐four percent of AVF were localized on the forearm: 74% in the distal and 20% in the proximal part. Mean duration of hemodialysis therapy was 20.80 ± 19.45 months. The mean time of AVF use was 15.9 ± 20.2 months. Until present, 38% have been dialyzed using AVF for 31.0 ± 18.8 months. Five patients died with functioning fistula. Eight patients initiated hemodialysis therapy with fistula. During further observation, the use of AVF increased to 62%. Elderly patients should not be denied creation of AVF as a rule. The outcome of AVF benefits more from acknowledging individual vascular conditions rather than age of the patient.     

Applications of fuzzy‐based linguistic patterns for the assessment of computer screen design quality

The main objective of this study was to develop a modeling framework which would unify different aspects of computer screen design and result in a quantitative criterion for an optimized computer screen format. The fuzzy set‐based linguistic design patterns were utilized as a tool to build this model. The linguistic patterns are based on categories of expressions related closely to natural language and truth values, which are close to a human designer's intuition. The proposed framework is capable of assessing the quality of computer screen design based on existing knowledge in human‐computer interface domain using the fuzzy‐based linguistic pattern approach. Exemplary patterns for an optimal screen density, information grouping, and some aspects of screen layout are presented, along with a sequence of calculations based on the exemplary screen format. This study showed that it is possible to achieve a rational and relatively easy to interpret assessment of different screen designs in the form of the degrees of truth. Such an evaluation criterion reflects the compatibility of a given screen design with the optimal one based on the current knowledge in the field. It is believed that the proposed methodological framework for computer screen design should significantly augment the efforts of human designers.     

Influence of hydrodynamic instability on the heat transfer coefficient during condensation of R134a and R404A refrigerants in pipe mini-channels

This paper presents the results of an investigation of the influence of hydrodynamic instabilities on heat transfer intensity during the condensation of R134a and R404A refrigerants in pipe mini-channels. The heat transfer coefficient h is a measure of the effectiveness of the condensation process. It is particularly important to determine the value of the coefficient in the two-phase condensation area in a compact condenser. In other condenser areas (i.e., precooling of superheated vapor and subcooling of condensate), the heat efficiency is substantially smaller. Hydrodynamic instabilities of a periodic nature have an influence on size changes in these areas. A decrease in the heat transfer coefficient h in the two-phase area results in decreased intensity of the heat removal process in the whole condenser.The experimental investigations were based on the condensation of R134a and R404A refrigerants in horizontal pipe mini-channels with internal diameters of d = 0.64; 0.90; 1.40; 1.44; 1.92; 2.30 and 3.30 mm. Disturbances of the condensation process were induced with a periodic stop and a repetition of the flow of the refrigerant.In the range of frequencies, f = 0.25–5 Hz, of the periodically generated disturbances, an unfavorable influence on the intensity of the heat transfer during the condensation process in pipe mini-channels was identified. The reduction in the intensity of the heat transfer during the condensation process, which was induced with hydrodynamic instabilities, was presented in the form of the dependence of the heat transfer coefficient h on the vapor quality x and the frequencies f of the disturbances.The influence of the refrigerant, the diameter of the mini-channels and the frequency f on the damping phenomenon of the periodical disturbances in the pipe mini-channels was identified.     

Characterization of reactively sputtered permeation barrier materials on polymer substrates

Transparent permeation barrier layers are not only used for food packaging but are also needed to encapsulate flexible electronic devices. Magnetron sputtering allows the deposition of high quality oxide barrier layers with a low water vapor and oxygen permeation. This paper compares different metal oxide layers which are deposited onto a polyethylene terephthalate (PET) film using a reactive dual magnetron sputtering process. The oxides of aluminum, silicon, titanium, zinc and a zinc-tin alloy are compared regarding their permeation barrier, structural and surface properties to determine the relationship between the layer structure and the gas permeation. Thereby, scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to characterize the morphology and surface structure of the layers and X-ray diffraction analysis (XRD) was used to determine the solid state phase.Cross-section images taken with SEM show a very compact structure for both aluminum oxide and zinc-tin oxide layers. These materials also have the lowest water vapor permeation compared to all other materials. Zinc oxide and titanium oxide layers both exhibit a columnar structure. Zinc oxide is polycrystalline and has a surprising low water vapor and oxygen permeation. In contrast to that the amorphous titanium oxide layers show a high water vapor and oxygen permeation which is not decreasing with an increasing layer thickness above 40 nm.