Experimental‐numerical research on the seismic performance of URM buildings made of lightweight AAC blocks / Experimentell‐numerische Untersuchung zum seismischen Verhalten von unbewehrten Mauerwerksgebäuden aus Porenbetonblöcken

Masonry walls constructed with lightweight AAC blocks and thin‐layer mortar meet the increasingly strict requirements of energy efficiency and sustainability. In this sense, they represent an excellent solution for modern buildings, not only for external cladding but also as loadbearing elements. Despite the possible advantages of using lightweight AAC masonry, a specific assessment of its seismic performance is mandatory in order to set design recommendations allowing to reach safety levels consistent with those required for other masonry types complying with EN 1998 standard requirements. A comprehensive study on the seismic performance of unreinforced masonry buildings made of lightweight AAC was carried out in an integrated experimental‐numerical approach. The experimental campaign provided the necessary information to setup a reliable numerical model to be extensively used to assess the seismic performance of a number of prototype AAC masonry buildings with different characteristics, by means of both linear and nonlinear static (pushover) analysis. The results of this systematic numerical assessment were eventually used to draft design recommendations, to set parameters (behaviour factors) to be used in linear analysis and to calibrate rules for simple buildings.     

Precursor system of liquid crystalline phase containing propolis microparticles for the treatment of periodontal disease: development and characterization

Precursor systems of liquid crystalline phase were prepared using the surfactant PPG-5-Ceteth-20, isopropyl myristate, and water; gelatin microparticles containing propolis were then added into these systems. Homogeneity of dispersion, the in-system microparticle morphology, and sedimentation behavior of each formulation were evaluated. The rheological and mechanical properties (hardness, compressibility, and adhesiveness), the work of syringing, and the propolis release profile were also evaluated. All the formulations exhibited pseudoplastic flow and thixotropy, and they displayed storage modulus, loss modulus, dynamic viscosity, and loss tangent that depended on temperature, frequency, and composition. Mechanical properties varied significantly among the formulations being affected by changes in the composition and temperature. Raising the concentration of surfactant and adding propolis microparticles significantly decreased the work of syringing. The drug release was non-Fickian (anomalous) and there was no significant difference between the tested systems in the times required for 10%, 30%, and 50% release of the initial drug loading.     

Inherent safety, ethics and human error

A patient is to have the damaged left kidney removed. To safeguard correctness of action several layers of expert checks have been performed prior to the operation, which results in the removal of the fully functional right kidney. Nobody asked the patient. The patient did not volunteer providing “unnecessary” information. The experts know everything …

An untidy house made out of flammable materials. A careless smoker left his lit cigarette unattended. A blow of wind and the house comes in flames. Would better construction materials have prevented the accident in spite of the carelessness of the inhabitant

A tricky medical condition which is expected to provoke a patient's fast health deterioration and their slow death. The doctor takes the initiative and responsibility of performing a risky operation. The patient's life is saved and their health is re-established.

This work is not, as initially intended, the result of a thorough investigation of accidents, neither contains a systematic collection of data that can support the conclusions or the suggestions made. It is in the main a compilation of personal views. These views have been established from the correlation of the results of numerous accident investigation reports with the causes of small and insignificant incidents. These incidents are related with the education of university students, regulations within an academic environment and from independent personal experience working in different countries and with people of different cultures. The analysis that follows, however, should not be perceived as a mere reference to university students and/or to a university environment. University is the place where the fundamental scientific and engineering principles are germinated while current and past university students are the future and current production and design engineers, respectively. The places where the presented incidents have occurred are not always relevant with the conclusions, thus they are not stated. The reason this article is presented here is that I believe that often, complex accidents, similarly to insignificant ones, often demonstrate an attitude which can be characterized as “inherently unsafe”. I take the view that the enormous human potential and the human ability to minimize accidents needs to become a focal point towards inherent safety. Restricting ourselves to human limitations and how we could “treat” or prevent humans from not making accidents needs to be re-addressed.

The purpose of this presentation is to highlight observations and provoke a discussion on how we could possibly improve the understanding of safety related issues. I do not intent to reject or criticize existing methodologies. (The entire presentation is strongly influenced by Trevor Kletz's work although our views are often different.)     

Improved in vitro anti-tumoral activity, intracellular uptake and apoptotic induction of gemcitabine-loaded pegylated unilamellar liposomes

Anaplastic thyroid carcinoma is one of the most aggressive and lethal solid carcinomas affecting humans. A major limit of the chemotherapeutic agents is represented by their low therapeutic index. In this work, we investigated the possibility of improving the anti-tumoral activity of gemcitabine by using pegylated unilamellar liposomes. Liposomes were made up of 1,2-dipalmitoyl-sn-glycero-3-phospocholine monohydrate/cholesterol/N-(carbonyl-methoxypolyethylene glycol-2000)-1, 2-distearoyl-sn-glycero-3-phosphoethanolamine (6:3:1 molar ratio) and they were prepared with a pH gradient to improve the gemcitabine loading capacity. The anti-tumoral efficacy of the liposomal formulation was tested in vitro on human anaplastic thyroid carcinoma cells (ARO) in culture, comparing the effects with those of the free drug. Gemcitabine-loaded unilamellar liposomes had a mean size approximately 200 nm with a zeta potential approximately -2 mV. The liposomal carrier noticeably improved the anti-tumoral activity of gemcitabine against ARO cells in terms of both dose-dependent cytotoxic effect and of drug exposition effect. Namely, gemcitabine-loaded liposomes showed a cytotoxic effect (58.2% increase of cell mortality at 1 microM with respect to free drug) after 12 h incubation, while the free drug showed a significant activity only after 72 h incubation. Moreover, a significant effect on the cell mortality appeared at 0.1 microM and 100% mortality was detected at a concentration of 1 microM of gemcitabine-loaded liposomes, while the free drug elicited the same effect at a concentration of 100 microM. The improved anti-tumoral activity of gemcitabine determined by the liposomal carrier was due to a greater intracellular uptake. The intracellular gemcitabine levels as a function of time showed a sinusoidal profile with peaks after 2 h, 6 h and 11 h, related to the cellular cycle of ARO. PARP cleavage and DNA fragmentation analysis provided clear evidence of the apoptosis induction in ARO cells by treatment with liposomally entrapped gemcitabine after 72 h incubation. Thus, gemcitabine-loaded liposomes may have a potential therapeutic relevance for the treatment of anaplastic thyroid carcinoma.     

Effect of phosphate binders on oxidative stress and inflammation markers in hemodialysis patients

It has been suggested that phosphate binders may reduce the inflammatory state of hemodialysis (HD) patients. However, it is not clear whether it has any effect on oxidative stress. The objective of this study was to evaluate the effect of sevelamer hydrochloride (SH) and calcium acetate (CA) on oxidative stress and inflammation markers in HD patients. Hemodialysis patients were randomly assigned to therapy with SH (n=17) or CA (n=14) for 1 year. Before the initiation of therapy (baseline) and at 12 months, we measured in vitro reactive oxygen species (ROS) production by stimulated and unstimulated polymorphonuclear neutrophils and serum levels of tumor necrosis factor α, interleukin-10, C-reactive protein, and albumin. There was a significant reduction of spontaneous ROS production in both groups after 12 months of therapy. There was a significant decrease of Staphylococcus aureus stimulated ROS production in the SH group. There was a significant increase in albumin serum levels only in the SH group. In the SH group, there was also a decrease in the serum levels of tumor necrosis factor α and C-reactive protein. Our results suggest that compared with CA treatment, SH may lead to a reduction in oxidative stress and inflammation. Therefore, it is possible that phosphate binders exert pleiotropic effects on oxidative stress and inflammation, which could contribute toward decreasing endothelial injury in patients in HD.