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.

Influence of Solvents and Adsorption of Organic Molecules on the Properties of CVD Synthesized 2D MoS2.

We present a simple method for modification of 2D materials by drop-casting of the organic molecule in solution on the 2D material under ambient conditions. Specifically, we investigated the adsorption of 6-(4,5-Dihydro-1H-imidazol-3-ium-2-yl)-2-(naphthalene-2-yl)benzothiazole methanesulfonate (L63MS) organic molecule on 2D MoS2. To better understand the effect of the organic molecule on the 2D material, we also investigated the impact of solvents alone on the materials' properties. The MoS2 samples were synthesized using ambient pressure chemical vapor deposition. Atomic force microscopy, Raman spectroscopy, photoluminescence spectroscopy and optical microscopy were used to characterize the samples. The measurements were performed after synthesis, after the drop-casting of solvents and after the drop-casting of organic molecule solutions. Our results indicate that the used organic molecule effectively adsorbs on and prompts discernible changes in the (opto)electronic properties of the 2D material. These changes encompass variations in the Raman spectra shape, alterations in the photoluminescence (PL) signal characteristics and modifications in excitonic properties. Such alterations can be linked to various phenomena including doping, bandgap modifications, introduction or healing of defects and that the solvent plays a crucial role in the process. Our study provides insights into the modification of 2D materials under ambient conditions and highlights the importance of solvent selection in the process.

Unifying fast computer-generated hologram calculation and prepress for new and existing production techniques.

Directed by successfully manufacturing the computer-generated hologram (CGH) using the computer-to-film (CtF) process, we present, to the best of our knowledge, a new method for low-cost and fast hologram manufacturing. This new method allows for advances in the CtF process and manufacturing using new techniques in hologram production. These techniques include computer-to-plate, offset printing, and surface engraving utilizing the same CGH calculations and prepress. With an advantage in cost and the possibility to be mass manufactured, the aforementioned techniques combined with the presented method have a solid foundation to be implemented as security elements.

Metal bioaccumulation in stygophilous amphipod Synurella ambulans in the hyporheic zone: The influence of environmental factors.

Given the increasing need to protect vulnerable freshwater ecosystems and make them more resilient to human use and climate change, biomonitoring of the hyporheic zone (HZ), which plays a critical role in pollution attenuation, is essential. The aim of the present study was to assess the potential of the amphipod species Synurella ambulans as a bioindicator of metal contamination in the HZ of the Sava River (Croatia). Amphipods were collected during the four seasons at two sampling sites (average sampling depth 55 cm) differing in type (agricultural and urban) and intensity (diffuse and point source contamination) of anthropogenic influence, one located upstream (Medsave), and the other downstream (Jarun) of the wastewater treatment plant discharge. Concentrations of Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Rb, Sn, Zn, Ca, K, Mg and Na were measured in the interstitial water, sediments and specimens of S. ambulans by HR ICP-MS. Physicochemical parameters (temperature, DO, O2 saturation, pH, conductivity, alkalinity, total water hardness, CODKMnO4, nutrients) were measured in the interstitial water, while organic carbon was measured in the interstitial water and sediments. Metal concentrations in interstitial water and sediments were below thresholds set by environmental quality standards. Metal concentrations in S. ambulans were classified as follows: higher at the Jarun site (Al, Cr, Fe, Ni, Pb, Sn), higher at the Medsave site (Cd, Cu, Rb) and mostly comparable at both sites (Co, Mn, Zn). Bioaccumulation factors were generally higher at Jarun, with average values ranging from 322 to 143,278 L kg-1. Bioaccumulation of metals in S. ambulans depended on various environmental factors, with metal exposure level and dissolved macro elements showing the strongest association with metals accumulated in S. ambulans. The findings provided the first evidence on the suitability of S. ambulans as a good bioindicator of chronic metal contamination in the HZ.

Direct Identification of Urinary Tract Pathogens by MALDI-TOF/TOF Analysis and De Novo Peptide Sequencing.

For mass spectrometry-based diagnostics of microorganisms, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is currently routinely used to identify urinary tract pathogens. However, it requires a lengthy culture step for accurate pathogen identification, and is limited by a relatively small number of available species in peptide spectral libraries (≤3329). Here, we propose a method for pathogen identification that overcomes the above limitations, and utilizes the MALDI-TOF/TOF MS instrument. Tandem mass spectra of the analyzed peptides were obtained by chemically activated fragmentation, which allowed mass spectrometry analysis in negative and positive ion modes. Peptide sequences were elucidated de novo, and aligned with the non-redundant National Center for Biotechnology Information Reference Sequence Database (NCBInr). For data analysis, we developed a custom program package that predicted peptide sequences from the negative and positive MS/MS spectra. The main advantage of this method over a conventional MALDI-TOF MS peptide analysis is identification in less than 24 h without a cultivation step. Compared to the limited identification with peptide spectra libraries, the NCBI database derived from genome sequencing currently contains 20,917 bacterial species, and is constantly expanding. This paper presents an accurate method that is used to identify pathogens grown on agar plates, and those isolated directly from urine samples, with high accuracy.

Computer-generated hologram manipulation and fast production with a focus on security application.

Motivated by the successful printing of a computer-generated hologram using the computer-to-film (CtF) graphic process, we present a further refined technique with increased resolution, applicable in security. The CtF process offers low cost and fast production while persevering high resolution, and it can make every hologram unique. In this paper, we present the improvement of the printing method, with several software modifications and the implementation of security features at different levels of production.

On the image inpainting problem from the viewpoint of a nonlocal Cahn-Hilliard type equation.

Motivated by the fact that the fractional Laplacean generates a wider choice of the interpolation curves than the Laplacean or bi-Laplacean, we propose a new non-local partial differential equation inspired by the Cahn-Hilliard model for recovering damaged parts of an image. We also note that our model is linear and that the computational costs are lower than those for the standard Cahn-Hilliard equation, while the inpainting results remain of high quality. We develop a numerical scheme for solving the resulting equations and provide an example of inpainting showing the potential of our method.

Utilizing standard high-resolution graphic computer-to-film process for computer-generated hologram printing.

The computer-generated hologram (CGH) has wide use in many fields but often comes at a high cost due to complex proprietary equipment. For this research, we developed a new robust computational method, and applied and tested common computer-to-film (CtF) technology to create affordable and high-resolution prints of CGHs that can be used primarily in security printing. The proposed method also allows for quick authentication with no need for a complex optical setup, while offering high-level security analysis through a simple yet robust system. Beyond the computational method, we based our research on testing material, protocol, and the optical measuring setup and derived an all-in-one, highly defined, conclusive, usable method capable of making every CGH unique.

Analysis of Fatty Acid Esters of Hydroxyl Fatty Acid in Selected Plant Food.

Metabolic syndrome, characterized by obesity, low-grade inflammation, insulin resistance, hyperglycemia, dyslipidemia and hypertension, is a major risk factor for cardiovascular mortality. Preclinical studies on recently discovered classes of lipids - fatty acid esters of hydroxy fatty acids (FAHFA) have revealed their anti-inflammatory and insulin-sensitizing potential. The FAHFA levels are significantly decreased in insulin-resistant individuals, their application exhibited anti-inflammatory effects and restoring the glucose-insulin homeostasis. The aim of our research was to analyze the overall FAHFA composition in a common diet, as only a partial FAHFA composition has been revealed so far (only the PAHSA subclass was analyzed in a few foods). A new approach to the FAHFAs analysis includes nano-LC and post-column modifier followed by negative ion mass spectrometry, in order to obtain maximum sensitivity. Analysis of different foods - oat (whole grain, coarse flakes and fine flakes), apple, clementine, lemon, strawberry, blueberry, mango, kiwi, avocado, pineapple, banana, onion, garlic, cherry tomato, carrot, parsley root, pepper and radish - exhibited wide inter-food variation in the FAHFA profiles. Sixteen analyzed FAHFAs (palmitic, oleic, palmitoleic and stearic hydroxy-esters) showed microgram to low nanogram levels (0.165 ng/g - 32 µg/g FW), with the highest abundancy in oat, clementine, garlic and pineapple. Stearic acid hydroxy stearic acid (SAHSA) was the most abundant FAHFA, especially in the food with antioxidative, anti-inflammatory and beneficial metabolic effects. In contrary, the PAHSA - previously proven to have the strongest antihyperglycemic and insulin-sensitizing effects, was not present in some foods (radish, avocado, mango, lemon, cherry tomato, kiwi). Our study proves the importance of overall FAHFA analysis in food (especially in a functional food), because of their potential metabolic benefits and possible future incorporation in special diets.