Changes in the physical properties of honey powder during storage

Honey powders produced by spray drying with the addition of Arabic gum and sodium caseinate were characterised in terms of the influence of storage time on the following physical properties: particle size, moisture content, water activity, bulk density, flowability and hygroscopicity. The storage affected those properties; after 12 weeks of storage, particle size decreased (except Arabic gum powder treated as a control sample), moisture content and water activity increased, hygroscopicity decreased. Changes in bulk density, particle size and moisture content caused the rise of Hausner ratio value; however, the powders were still characterised by a very good flow properties and low cohesiveness. The colour of reconstituted powders was also affected by storage; in most of samples, the darkening, reduction in redness and yellowness were observed. Colour parameters were the most stable in powders obtained with the addition of 2% w/w of sodium caseinate.     

The Influence of Betulin and Its Derivatives EB5 and ECH147 on the Antioxidant Status of Human Renal Proximal Tubule Epithelial Cells

Betulin and its derivatives, 28-propyne derivative EB5 and 29-diethyl phosphonate analog ECH147, are promising compounds in anti-tumor activity studies. However, their effect on kidney cells has not yet been studied. The study aimed to determine whether betulin and its derivatives—EB5 and ECH147—influence the viability and oxidative status of human renal proximal tubule epithelial cells (RPTECs). The total antioxidant capacity of cells (TEAC), lipid peroxidation product malondialdehyde (MDA) level, and activity of antioxidant enzymes (SOD, CAT, and GPX) were evaluated. Additionally, the mRNA level of genes encoding antioxidant enzymes was assessed. Cisplatin and 5-fluorouracil were used as reference substances. Betulin and its derivatives affected the viability and antioxidant systems of RPTECs. Betulin strongly reduced TEAC in a concentration-dependent manner. All tested compounds caused an increase in MDA levels. The activity of SOD, CAT, and GPX, and the mRNA profiles of genes encoding antioxidant enzymes depended on the tested compound and its concentration. Betulin showed an cisplatin-like effect, indicating its nephrotoxic potential. Betulin derivatives EB5 and ECH147 showed different impacts on the antioxidant system, which gives hope that these compounds will not cause severe consequences for the kidneys in vivo.     

The influence of sodium caseinate on the physical properties of spray‐dried honey

The aim of this work was to spray dry honey (rape and buckwheat varieties) with Arabic gum (AG) as a carrier alone or in combination with sodium caseinate (1% and 2% w/w NaCas) as a drying aid. Powder recovery ranged from 66.2 ± 0.7% to 75.8 ± 4.9%, and the values were significantly higher for samples containing NaCas. Powders were characterised by good flowability, the addition of NaCas had positive impact on this factor. However, the hygroscopicity of protein‐containing powders was higher, especially at 2% w/w of NaCas. Powders hygroscopicity was related to particle size: AG powder of the smallest particle size was the most hygroscopic, while the particle size did not affected flowability, which was strongly related to the feed solution composition. Based on the obtained results, it was concluded that the addition of 1% w/w of NaCas as a drying aid during buckwheat and rape honey spray drying with Arabic gum as a carrier is favourable, while the further increase of protein content does not give additional benefits.     

The Role of AKT/mTOR Pathway in Stress Response to UV-Irradiation: Implication in Skin Carcinogenesis by Regulation of Apoptosis,Autophagy and Senescence

Induction of DNA damage by UVB and UVA radiation may generate mutations and genomic instability leading to carcinogenesis. Therefore, skin cells being repeatedly exposed to ultraviolet (UV) light have acquired multilayered protective mechanisms to avoid malignant transformation. Besides extensive DNA repair mechanisms, the damaged skin cells can be eliminated by induction of apoptosis, which is mediated through the action of tumor suppressor p53. In order to prevent the excessive loss of skin cells and to maintain the skin barrier function, apoptotic pathways are counteracted by anti-apoptotic signaling including the AKT/mTOR pathway. However, AKT/mTOR not only prevents cell death, but is also active in cell cycle transition and hyper-proliferation, thereby also counteracting p53. In turn, AKT/mTOR is tuned down by the negative regulators being controlled by the p53. This inhibition of AKT/mTOR, in combination with transactivation of damage-regulated autophagy modulators, guides the p53-mediated elimination of damaged cellular components by autophagic clearance. Alternatively, p53 irreversibly blocks cell cycle progression to prevent AKT/mTOR-driven proliferation, thereby inducing premature senescence. Conclusively, AKT/mTOR via an extensive cross talk with p53 influences the UV response in the skin with no black and white scenario deciding over death or survival.     

20th century acidification and warming as recorded in two alpine lakes in the Tatra Mountains (South Poland, Europe)

Sediment profiles of two alpine lakes located in the Tatra Mountains, the Toporowy Staw Ni?ni (TSN) and the Zielony Staw G?sienicowy (ZSG), were studied for their chronology, lithology, diatom and cladoceran remains. The sediment sequences, 50 cm long from TSN and 30 cm long from ZSG, were deposited during the last 1000 and 300 years, respectively. Vertical changes in lithology, diatom and Cladocera allow the reconstruction of three periods in the lakes' evolution: mild climatic conditions during Medieval Warm Period (MWP, only in TSN), severe conditions between the end of 14th and 19th centuries, identified as the Little Ice Age (LIA), and 20th century warming. The LIA was recorded in the sediments of both lakes in the form of intensified erosion and lower lake ecosystem productivity, as indicated by organic matter lower content, changes in diatom species composition, and decline in Daphnia.The 20th century was a time of acidification in both lakes. The scale of acidification was assessed based on the decline in diatom-inferred pH (DI-pH). DI-pH dropped by 1.2 pH units during the last century in TSN and by 0.4 pH unit in ZSG. The decline of DI-pH was noted in both lakes, but its intensity was clearly higher in TSN due to the lower acid neutralisation capacity (ANC) of this lake. The lower pH during the final decades of the 20th century was lethal to some water organisms while attracting others, such as Daphnia. The Daphnia population increased after the pH drop, probably due to the high food flexibility of this genus. A similar increase was not observed in ZSG, where planktonivorous fishes were introduced in the 1940s, which effectively limited the crustacean plankton density.     

Modifier Role of Common RET Variants in Sporadic Medullary Thyroid Carcinoma

Background: Although the disease-causing effect of pathogenic variants in the gene RET has been unambiguously identified, there is a lack of consensus regarding the possible impact of common variants in this gene. Our study aimed to test whether variants in exons 10, 11, and 13–16 that are commonly detected during routine diagnostic testing might have any modifying effect on MTC. Methods: In sporadic MTC patients with no pathogenic variants but with or without common variants in RET, the following variants were evaluated: rs1799939 (p.G691S), rs1800861 (p.L769=), rs1800862 (p.S836=), rs2472737 in intron 14, and rs1800863 (p.S904=). Results: After Bonferroni correction, none of the variants were statistically significantly associated with disease outcome when analysed independently. The MTC group was divided into three genetically different clusters by unsupervised k-means clustering. Those clusters differed significantly in the age at diagnosis. A trend towards the association of given clusters with metabolic disorders and with remission state was identified. Conclusions: Although common variants in RET are not responsible for the risk of MTC, their analysis might turn out useful in the prediction of a patient’s clinical outcome. Importantly, this analysis would come with no additional cost in laboratories with a diagnostic procedure based on exon sequencing.     

Polyetherols from isocyanuric acid and propylene carbonate

A new method for the synthesis of polyetherols containing perhydro‐1,3,5‐triazine rings by the reaction of isocyanuric acid and an excess of propylene carbonate is described. The reaction was studied in the presence of various catalysts and with varying substrate molar ratios. The structures and physical properties of the products were also studied. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2130–2138, 2005