Microplastics encapsulation in aragonite: efficiency, detection and insight into potential environmental impacts.

Plastic pollution in aquatic ecosystems has become a significant problem especially microplastics which can encapsulate into the skeletons of organisms that produce calcium carbonates, such as foraminifera, molluscs and corals. The encapsulation of microplastics into precipitated aragonite, which in nature builds the coral skeleton, has not yet been studied. It is also not known how the dissolved organic matter, to which microplastics are constantly exposed in aquatic ecosystems, affects the encapsulation of microplastics into aragonite and how such microplastics affect the mechanical properties of aragonite. We performed aragonite precipitation experiments in artificial seawater in the presence of polystyrene (PS) and polyethylene (PE) microspheres, untreated and treated with humic acid (HA). The results showed that the efficiency of encapsulating PE and PE-HA microspheres in aragonite was higher than that for PS and PS-HA microspheres. The mechanical properties of resulting aragonite changed after the encapsulation of microplastic particles. A decrease in the hardness and indentation modulus of the aragonite samples was observed, and the most substantial effect occurred in the case of PE-HA microspheres encapsulation. These findings raise concerns about possible changes in the mechanical properties of the exoskeleton and endoskeleton of calcifying marine organisms such as corals and molluscs due to the incorporation of pristine microplastics and microplastics exposed to dissolved organic matter.

Improvement of Metal-Doped ß-TCP Scaffolds for Active Bone Substitutes via Ultra-Short Laser Structuring.

Various efforts have been made to develop antibacterial biomaterials capable of also sustaining bone remodulation to be used as bone substitutes and reduce patient infection rates and related costs. In this work, beta-tricalcium phosphate (ß-TCP) was chosen due to its known biocompatibility and use as a bone substitute. Metal dopants were incorporated into the crystal structure of the ß-TCP, and disks were produced from this material. Magnesium and strontium, as well as copper and silver, were chosen as dopants to improve the osteogenic and antibacterial properties, respectively. The surface of the ß-TCP samples was further modified using a femtosecond laser system. Grid and line patterns were produced on the plates' surface via laser ablation, creating grooves with depths lower than 20 µm and widths between 20 and 40 µm. Raman and FTIR analysis confirmed that laser ablation did not result in the degradation or phase change of the materials, making it suitable for surface patterning. Laser ablation resulted in increased hydrophilicity of the materials, as the control samples (non-ablated samples) have WCA values ranging from 70° to 93° and become, upon laser ablation, superwicking surfaces. Confocal measurements show an increase in specific surface area of 50% to 200% compared to the control. Overall, the results indicate the potential of laser ablation to improve the surface characteristics of ß-TCP, which may lead to an improvement in the antibacterial and osteogenic properties of the produced materials.

Green Nanocoatings Prepared by Crosslinking Self-Assembled Fatty Acids on Metals.

Self-assembled monolayers (SAMs) are an important element of modern nanotechnology and surface functionalization. However, their application is still limited because they are easily removed from the surface of the object in corrosive environments. Crosslinking would make SAMs more resistant to the corrosive environment they are exposed to. In this work, how to strongly crosslink SAMs made of non-toxic and biodegradable fatty acids on metal surfaces using ionizing radiation has been demonstrated for the first time. The crosslinked nanocoatings are stable over time and have significantly improved properties compared to SAMs. Thus, crosslinking opens up the possibility of using SAMS in a variety of different systems and on different materials for surface functionalization to achieve stable and durable surface properties such as biocompatibility or selective reactivity.

Swelling and Viscoelastic Properties of Cellulose-Based Hydrogels Prepared by Free Radical Polymerization of Dimethylaminoethyl Methacrylate in Cellulose Solution.

The grafting of a stimuli-responsive polymer (poly(dimethylaminoethyl methacrylate)) onto cellulose was achieved by performing free radical polymerization of a vinyl/divinyl monomer in cellulose solution. The grafting and crosslinking efficiency in the material have been increased by subsequent irradiation of the samples with ionizing radiation (doses of 10, 30, or 100 kGy). The relative amount of poly(dimethylaminoethyl methacrylate) in the prepared hydrogels was determined by infrared spectroscopy. The swelling behavior of the hydrogels was studied thoroughly, including microgelation extent, equilibrium swelling, and reswelling degree, as well as the dependence on the gelation procedure. The dynamic viscoelastic behavior of prepared hydrogels was also studied. The tan δ values indicate a solid-like behavior while the obtained hydrogels have a complex modulus in the range of 14-39 kPa, which is suitable for hydrogels used in biomedical applications. In addition, the incorporation of Ag particles and the adsorption of Fe3+ ions were tested to evaluate the additional functionalities of the prepared hydrogels. It was found that the introduction of PDMAEMA to the hydrogels enhanced their ability to synthesize Ag particles and absorb Fe3+ ions, providing a platform for the potential preparation of hydrogels for the treatment of wounds.

THE ENIGMA OF LEWY BODY DEMENTIA: A CASE REPORT.

Lewy body dementia is a progressive neurodegenerative disease and is considered to be the second most common cause of dementia in the elderly. Because of the complexity of clinical presentation, it is often misdiagnosed and mistaken for other dementias, which may result in administering inappropriate therapy, and thus worsening of the patient condition. We reviewed a case of a 71-year-old patient whose clinical presentation gradually occurred with complex visual hallucinations, atypical extrapyramidal motor symptoms, fluctuating cognitive impairments with delirious episodes, and oscillating syncope. Depressive mood, impaired daily functioning and sensitivity to antipsychotics were also noted. Extensive diagnostic workup was performed with neuropsychological testing and use of single-photon emission computerized tomography. Considering the clinical presentation and diagnostic procedures performed, the diagnosis of Lewy body dementia was set and pharmacotherapy was revised. We discuss the importance of taking overall clinical presentation and diagnostic treatment in consideration and applying appropriate therapy to slow down the progression of the disease and exacerbation of the patient's psychological functions.

Optimizing the preparation procedure of self-assembled monolayer of stearic acid for protection of cupronickel alloy.

The aim of this work is to examine the possibility of CuNi protection in chloride media by self-assembled monolayers (SAMs) of stearic acid (SA). In order to obtain a compact, well ordered monolayer, that will provide long term protection, different SAM preparation procedures are studied. The influence of CuNi pretreatment, SA solution temperature and temperature of the drying period followed after the SA treatment on the protective properties of stearic acid self-assembled layer are examined by electrochemical methods and surface analysis techniques. The obtained results show that for complete self-assembled film formation it is necessary to have a drying period after exposing the sample to the stearic acid solution. Heating of the SA solution and drying period at higher temperatures result in layers with better stability in chloride media. The most compact surface layer, that provides long lasting and efficient protection to the underlying alloy, is obtained when prior to SA solution exposure an oxide layer on CuNi surface was formed at elevated temperatures.

[The relationship between alexithymia and morbidity]. / Povezanost aleksitimije i morbiditeta.

Alexithymia is a tendency to experience psychological distress in the form of somatic symptoms. Alexithymia is a syndrome that is defined by the inability to recognize and express emotions. It is a common feature in patients with psychoactive abuse disorders, post-traumatic stress disorder, and psychosomatic disorders such as gastrointestinal complaints, migraine, dermatological symptoms, and irritable bowel syndrome. Alexithymia is associated with a failure to use adaptive affect regulation such as modulating arousal, appropriately expressing or suppressing emotions, tolerating painful emotions and cognitive assimilation. Alexithymia is presumed to play a very important role in the pathogenesis of medically unexplained physical symptoms and it is a risk factor for a psychosomatic condition. It is of clinical importance that the majority of patients with medically unexplained physical symptoms are able to recognize that their physical symptoms may be related to their depression or anxiety disorder which are the most common mental disorders.

Influence of surface layer on mechanical and corrosion properties of nickel-titanium orthodontic wires.

OBJECTIVE: To analyze the effect of various coating formulations on the mechanical and corrosion properties of nickel-titanium (NiTi) orthodontic wires. MATERIALS AND METHODS: Uncoated, rhodium-coated, and nitrified NiTi wires were observed with a three-point-bend test, surface roughness (Ra) measurement, scanning electron microscopy, energy dispersive spectroscopy, and electrochemical testing (open circuit potential, electrochemical impedance spectroscopy, and cyclic polarization scan). Differences in the properties of tested wire types were analyzed with analysis of variance and Tukey post hoc test. RESULTS: Uncoated and nitrified NiTi wires showed similar mechanical and anticorrosive properties, while rhodium-coated NiTi wires showed the highest Ra and significantly higher modulus of elasticity, yield strength, and delivery of forces during loading but not in unloading. Rhodium-coated NiTi wires also had the highest corrosion current density and corrosion potential, lowest impedance modulus, and two time constants on Bode plot, one related to the Rh/Au coating and the other to underlying NiTi. CONCLUSION: Working properties of NiTi wires were unaffected by various coatings in unloading. Nitrification improved corrosion resistance. Rhodium coating reduced corrosion resistance and pronounced susceptibility to pitting corrosion in artificial saliva because of galvanic coupling between the noble coating and the base alloy.