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Since its outbreak in early 2020, the COVID-19 pandemic has diverted resources from non-urgent and elective procedures, leading to diagnosis and treatment delays, with an increased number of neoplasms at advanced stages worldwide. The aims of this study were to quantify the reduction in surgical activity for indeterminate thyroid nodules during the COVID-19 pandemic; and to evaluate whether delays in surgery led to an increased occurrence of aggressive tumours.

Despite the recent increase in the number of mayfly studies in karst freshwater habitats, their biology and ecology in springs are still poorly characterized. Therefore, we studied mayfly assemblages in a European karst rheocrene spring at five microhabitats monthly over a one-year period. Three species were recorded: Baetis alpinus(Pictet, 1843), Baetis rhodani(Pictet, 1843) and Rhithrogena braaschi(Jacob, 1974). The latter species represents a new record for the fauna of Bosnia and Herzegovina. All three species inhabited all studied microhabitats but with varying abundance. Individual species were associated with a specific substrate type and/or water velocity and/or water depth. The grazer/scraper Rh. braaschiwas most common at microhabitats with inorganic substrate (cobbles, mixture of pebbles and sand), moderate water velocity and higher water depth. The rheophilic grazer/scraper and gatherer/collector B. alpinuswas most common at microhabitats with mosses and highest water velocity. The grazer/scraper and gatherer/collector B. rhodaniwas recorded at all microhabitats, yet due to its preference for moderate water velocity, the highest number of individuals were collected from cobbles. We recorded movements of mayfly nymphs among the available microhabitats during their life cycles, due likely to their dietary requirements and search for suitable refugia. Baetis alpinushas a bivoltine, B. rhodanipolyvoltine and Rh. braaschiunivoltine life cycle with a long emergence period. The results presented here contribute to the knowledge of spring and mayfly ecology.

The purpose of this paper is to present two simplified methods which involve inexpensive equipment and which can be applied by all analyst who have to determine chlormequat residues in pears. The two methods use the extraction with methanol and purification by formation of ion-pair with sodium tetraphenylborate. A first method is a high-performance thin layer chromatography (HPTLC), the second is high-performance liquid chromatography (HPLC) with conductimetric detector. The results obtained for the same samples by the two methods are quite comparable. These two methods are rapid and particularly the thin-layer chromatography.

The purpose of this paper is to present two simplified methods which involve inexpensive equipment and which can be applied by all analyst who have to determine chlormequat residues in pears. The two methods use the extraction with methanol and purification by formation of ion-pair with sodium tetraphenylborate. A first method is a high-performance thin layer chromatography (HPTLC), the second is high-performance liquid chromatography (HPLC) with conductimetric detector. The results obtained for the same samples by the two methods are quite comparable. These two methods are rapid and particularly the thin-layer chromatography.

A three-dimensional electrode cell with cross-flow of current and electrolyte is modelled for galvanostatic and pseudopotentiostatic operation. The model is based on the electrodeposition of copper from acidified copper sulphate solution onto copper particles, with an initial concentration ensuring a diffusion-controlled process and operating in a batch recycle mode. Plug flow through the cell and perfect mixing of the electrolyte in the reservoir are assumed. Based on the model, the behaviour of reacting ion concentration, current efficiency, cell voltage, specific energy consumption and process time on selected independent variables is analysed for both galvanostatic and pseudopotentiostatic modes of operation. From the results presented it is possible to identify the optimal values of parameters for copper electrowinning.

Water electrolysis from acidified solution was used as a model system to investigate the net contribution of hydrogen bubbles to the pressure drop increase in a three-dimensional electrode. A bed of silvered glass beads in both fixed and fluidized state was used, assuming an unchanging particle surface during the experiments. Pressure drop behaviour with time was measured for different experimental conditions and presented relative to the pressure drop determined for a bubble free bed. Parameters, such as current density, electrolyte velocity and particle size, greatly influence the relative pressure drop behaviour in the three-dimensional electrode. A sudden increase in the pressure drop occurs with the appearance of a gas phase in the bed, reaching a constant value (plateau) after a certain time; this plateau corresponds to steady state conditions. The pressure drop increases with increasing current density. This increase is in the range 40-150% relative to the bubble free electrolyte flow through the bed. Electrolyte flow-rate also strongly influences the pressure drop in the hydrogen evolving fixed bed electrode. It was observed that the relative pressure drop decreases with increasing electrolyte velocity. At higher flow rates, peaks occur on the pressure drop-time curves, indicating the existence of channeling inside the bed in which spouting occurs. The time to reach the pressure drop plateau decreases with increasing electrolyte velocity as do the time intervals corresponding to maximum pressure drop values. At the minimum fluidization velocity the peaks disappear and the relative pressure drop decreases with time, tending to approach a constant value. For hydrogen evolution in the fluidized bed, the pressure drop is lower than that measured in the absence of gas, and reason for this decrease being the gas hold-up in the bed.

An experiment was conducted on the immunization of guinea-pigs with homogenized rat tissues (spleen, intestine and testes) mixed with Freund's adjuvant. Tissues were obtained one day after lethal whole-body x-ray exposure. Anaphylactic sensitivity, as demonstrated by the Schultz-Dale reaction after desensitization in vitro with the blood sera of normal rats, has shown that the spleen of irradiated animals has some antigenic compounds which are not present in the blood sera of normal rats, but which exist in the sera of irradiated rats. Muscle organs from intestinal tissue sensitized animals were much less specifically activated, and testicular tissue did not manifest any antigenic specificity. It is proposed that there is no correlation between the tissue radiosensitivity and the radiation-induced change of its antigenicity.

Guinea-pigs were injected with homogenized spleens of normal or irradiated rats (one day after 1000 r) or with autolyzed spleens of normal rats. Schultz-Dale reactions after different desensitizations in vitro with sensitizing materials were determined. The experimental data provide additional evidence for the existence of some new antigenic component(s) in irradiated spleen. This component is not radiation specific, for it is present in autolyzed spleen too. Some preliminary results are given, showing that previous immunization with such tissues renders the rats more susceptible to the lethal effect of irradiation.

An intravenous injection of homologous intestinal extract induced in about 60 per cent of total-body x-irradiated (400 or 450 r) guinea-pigs a reaction with symptoms resembling in some respects the anaphylatic reaction. The reaction was maximal about the eighth post-irradiation day. The reaction was observed when extracts deriving either from normal or from irradiated animals were used. The attempt to sensitize normal guinea-pigs with the intestinal extract was not successful.

Based on graphene nanoplatelets capability to build block composites, as well as well-known electrochemical characteristic of the manganese oxide materials, in the present research, a nanocomposite, formed from graphene nanoplatelets (GNP) and manganese(IV)-oxide (MnO2) nanoparticles, has been proposed as a novel and convenient support for enzyme immobilization. Performance of screen printed carbon electrodes (SPCEs) was significantly improved after their modification with GNP@MnO2(SPCE/GNP@MnO2). The polyphenolic index biosensor was prepared by applying the drop coating technique using laccase and Nafion®. Developed biosensor shows a fast and reliable amperometric response toward caffeic acid, as a model compound, at operating potential of +0.40 V (vs Ag/AgCl), with a wide linear range and detection limit of 1.9 ?mol l?1. Developed procedure was successfully applied for the determination of polyphenolic indexes in wine samples. Recovery tests indicate excellent accuracy and precision of the method, concluding that the biosensor can offer a fast, accurate, reliable and precise determination of the polyphenolic index. More importantly, our results suggest a great potential for the application in real samples.

AN increase of the insulin resistance was observed in fasted adult albino rats if they previously were exposed to 600 r. of X-rays.