Determination of 3,4,5-Trihydroxybenzoic Acid Exploiting a Visible-Light-Driven Photoelectrochemical Platform: Application in Wine and Tea Samples

The present work is based on the development and application of a photoelectrochemical method for the amperometric determination of 3,4,5-trihydroxybenzoic acid in different samples. The method is based on the use of a photoelectrochemical platform based on a glass slide coated with fluorine-doped tin oxide, which has been modified with cadmium sulfide and poly(D-glucosamine) and subjected to a light-emitting diode (LED) lamp. The photoelectrochemical platform was sensitive to the increase of the concentration of the antioxidant 3,4,5-trihydroxybenzoic acid in the solution. Under the optimized experimental conditions, the photoelectrochemical method presented a linear response for a 3,4,5-trihydroxybenzoic acid concentration ranging from 0.2 up to 500 μmol L-1. The method was applied to 3,4,5-trihydroxybenzoic acid determination in samples of wines and teas with recoveries between 95.88 and 101.72%. The results obtained suggest that the developed platform is a promising tool for quantifying the 3,4,5-trihydroxybenzoic acid.

Implementation of Static Telecytology Applications for Accreditation Purposes According to ISO 15189

Telecytology can be defined as the process of diagnostic cytology performed on digital images. The process of diagnostic cytology performed on digital images can be used for teaching, professional examinations, obtaining expert opinions on severe cases, and routine diagnosis of the entire laboratory workload. Ηowever, little information exists about its possible use for proficiency testing purposes. The existing studies have found a high (90%–95%) concordance between telecytological and glass slide diagnoses, but they refer to a small number of cases. Thus, the purpose of the chapter is to examine the feasibility of developing a proficiency testing scheme for cytology labs wishing to be accredited according to ISO 15189:2012 by using low-cost telemedical applications.

Secondary ice production during the break-up of freezing water drops on impact with ice particles

We provide the first dedicated laboratory study of collisions of supercooled water drops with ice particles as a secondary ice production mechanism. We experimentally investigated collisions of supercooled water drops (∼ 5 mm in diameter) with ice particles of a similar size (∼ 6 mm in diameter) placed on a glass slide at temperatures >-12 ∘C. Our results showed that secondary drops were generated during both the spreading and retraction phase of the supercooled water drop impact. The secondary drops generated during the spreading phase were emitted too fast to quantify. However, quantification of the secondary drops generated during the retraction phase with diameters >0.1 mm showed that 5–10 secondary drops formed per collision, with approximately 30 % of the secondary drops freezing over a temperature range between −4 and −12 ∘C. Our results suggest that this secondary ice production mechanism may be significant for ice formation in atmospheric clouds containing large supercooled drops and ice particles.

Galactose-Binding C-Type Lectin Promotes Cellular Aggregation of Coelomocytes in Sea Cucumber

Echinoderms have a large coelomic cavity containing coelomocytes. When the coelomic fluid is removed from the cavity, the cells aggregate immediately. We found that a fraction or an extract of the intestine of the sea cucumber, Apostichopus japonicus, markedly accelerated cellular movement and aggregation on a glass slide, and this effect was clearly inhibited by galactose. We successfully purified the aggregation-promoting factor, a 16 kDa protein, from the intestine. TOF-MS analysis followed by de novo sequencing revealed that the protein is a C-type lectin. RNA-seq data and cDNA cloning demonstrated the factor to be a novel lectin, named AjGBCL, consisting of 158 aa residues in the mature form. Microscopic observation revealed that most of the aggregating cells moved toward aggregates and not to an intestinal fragment, suggesting that AjGBCL is not a chemoattractant but a cellular aggregation-inducing factor that may induce aggregates to release chemoattractant. We report, for the first time, an endogenous molecule that promotes coelomocyte aggregation in echinoderms.

Quantitative study of activated sludge population structure

A quantitative study of the population structure of activated sludge is an important component of biological wastewater treatment control. However, in the studying of live samples of the activated sludge, some complications arise, in particular, associated with the relatively short time of the subsample suitability. A subsample is the part of the sample that is placed on a glass slide and in which organisms are counted. The issue of optimization of counts of organisms with large amplitude of population density is considered. The results of counting ciliated protozoa in activated sludge were described. The samples were counted in 45 sub-samples of 25 µl each. An average of 10 counts was required to achieve high reliability in determining population densities with more than or equal to 1 specimen per 25 µl in sub-samples. For small population densities (less one specimen per 25 µl) of free-swimming, crawling, and sessile ciliates, 30 counts are necessary. When the density of colonial protozoan populations is established, the number of counts should be increased to 40, especially when colonies with significant differences in the number of zooids are found.

Substrate Critical Effect on the Structural and H2 Gas Sensing Characteristics of Solution-Processed Zn0.075Cu0.025O Films

In this study, we report the synthesis of Zn0.075Cu0.025O films by chemical bath deposition to determine the effect of substrate (glass slide or ZnO seed layer) on the structural and H2 gas sensing properties of the produced films. The crystal phase, structural topography, surface morphology and functional groups of the as-synthesized films as well as H2 gas sensing properties were investigated. Although both films have a hexagonal wurtzite structure, ZnO seed layer-based Zn0.075Cu0.025O film is more crystalline than glass slide-based Zn0.075Cu0.025O films. ZnO seed layer-based Zn0.075Cu0.025O films exhibited much more nanorod and less nanosphere forms compared to glass slide-based Zn0.075Cu0.025O films. EDX analysis and Raman spectra of both samples confirmed the presence of defects in Cu:ZnO samples. ZnO seed layer-based sensors showed higher response (140%) and lower operating temperature (80°C) compared to glass slide-based sensors (87% response and 140°C operating temperature). The most important thing to note here is that the fabricated sensors exhibited high response at room temperature. The responses at room temperature was found as 46% and 23% for the ZnO seed layer-based and glass slide-based sensors, respectively. Sensors operating at room temperature are especially important for commercial applications.

Improvement in Tear Ferning Patterns of Sheep Tears After Addition of Various Electrolyte Solutions

Objective: This study aimed to improve the tear ferning (TF) patterns in the sheep tears after the addition of various electrolyte solutions in different proportions.Animal Studied: Sheep were located at a small farm in the outskirts of Riyadh, Saudi Arabia. The sheep had no ocular disorders or diseases, and none of the female sheep were pregnant.Methods: Tear samples (20 μl) were collected from the right eyes of seven healthy sheep (five female sheep and two male sheep; age 7–36 months with an average of 17.0 ± 10.3 months). A tear sample (1 μl) from each sheep was dried on a microscopic glass slide at 22°C and <40% humidity. The TF patterns were graded based on the five-point grading scale in 0.1 increments. Homogenous mixtures were prepared by mixing tears from each sheep (0.5 μl) with various electrolyte solutions in different proportions (1:1, 1:2, 1:4, 1:6, 1:8, and 1:10). A sample of each mixture (1 μl) was dried on a glass slide, and the TF patterns for each mixture were observed, recorded, graded, and compared with those of the corresponding pure sheep tears. In addition, each sheep tear sample (0.5 μl) was diluted with pure water (0.5 μl) and the TF images were recorded and graded to test the dilution effect.Results: General improvement was noted in TF grades after the addition of electrolyte solutions, ranging from 1.7–1.4 to 1.3–0.3 regardless of the ratio between the electrolyte solutions and sheep tears within the mixture. TF grades of sheep tear samples improved significantly after adding different volumes of calcium chloride solution. Similar improvements in TF grades were observed when magnesium chloride hexahydrate and sodium dihydrogen phosphate solutions were used as the electrolytes. Some improvements in the TF grades occurred with the addition of potassium chloride to sheep tear samples. There was little improvement in TF grades after the addition of sodium chloride solution.Conclusion: Tear ferning grades of sheep tear samples improved when mixed with a number of electrolyte solutions at different volumes, in particular with calcium chloride or magnesium chloride solutions. Some improvements in TF grades were seen with sodium dihydrogen phosphate or potassium chloride solution added as the electrolyte. Clearly, divalent electrolytes lead to a greater improvement in TF grades of sheep tear samples as compared with sodium dihydrogen phosphate or monovalent electrolytes.

Validation of grading of non-invasive urothelial carcinoma by digital pathology for routine diagnosis

Background Pathological grading of non-invasive urothelial carcinoma has a direct impact upon management. This study evaluates the reproducibility of grading these tumours on glass slides and digital pathology. Methods Forty eight non-invasive urothelial bladder carcinomas were graded by three uropathologists on glass and on a digital platform using the 1973 WHO and 2004 ISUP/WHO systems. Results Consensus grades for glass and digital grading gave Cohen’s kappa scores of 0.78 (2004) and 0.82 (1973). Of 142 decisions made on the key therapeutic borderline of low grade versus high grade urothelial carcinoma (2004) by the three pathologists, 85% were in agreement. For the 1973 grading system, agreement overall was 90%. Conclusions Agreement on grading on glass slide and digital screen assessment is similar or in some cases improved, suggesting at least non-inferiority of DP for grading of non-invasive urothelial carcinoma.

Secondary ice production during the break-up of freezing water drops on impact with ice particles

We experimentally investigated collisions of supercooled water drops (∼ 5 mm in diameter) with ice particles of a similar size placed on a glass slide at temperatures T ≥ −12 °C. Our results showed that secondary drops were generated during both the spreading and retraction phase of the supercooled water drop impact. The secondary drops generated during the spreading phase were emitted too fast to quantify. However, quantification of the secondary drops generated during the retraction phase with diameters > 0.1 mm showed that 5–10 secondary drops formed per collision, with approximately 30 % of the secondary drops freezing over a temperature range of −4 °C ≤ T ≤ −12 °C. Our investigation provides the first dedicated laboratory study of collisions of supercooled water drops with ice particles as a secondary ice production mechanism. Our results suggest that this secondary ice production mechanism may be significant for ice formation in atmospheric clouds containing large supercooled drops and ice particles.