Chemical sulphate corrosion on cement composites in various model environments

Background: Cementitious composites, which are subject to increasing demands, are often exposed to various external attacks, such as aggressive groundwater and surface water, chemicals in the soil, gas penetration, or phenomena related to water freezing and melting. One of the most common reasons for the deterioration of cement composites is the corrosion process. Corrosion results in irreversible damage that occurs during the chemical reaction of the material with the components of the environment. Methods: The paper deals with experimental study of chemical sulphate corrosion of cement composites prepared from three types of cement: ordinary Portland cement; sulphate-resistant cement; and special hybrid cement, and industrial by-products and wastes: silica fume, zeolite and a special mineral admixture based on blast furnace granular slag as cement partial substitutes. Samples of cement composites were subjected to corrosion experiments in a sulphate environment, which took place in the laboratory under model conditions for 180 resp. 270 days. Results: The deterioration parameters: changes in the weight and thickness of the samples, surface and mineralogical changes, leachability of the basic components of the cement matrix as well as changes in the liquid phase proved the degradation process due to chemical sulphate corrosion, model solutions of H2SO4 with pH 3 and 4, and solution of MgSO4 with c (SO4 2 - ) = 3 and 10 g /L. Conclusion: By comparing the leachability of the alkali components from cement composites, it can be concluded that for the most aggressive model solution (H2SO4 with pH 3), both slagcontaining formulations are the most stable in terms of the total ratio of leached calcium and silicon. This finding is also supported by the results of water absorbency tests, which confirmed that despite the increase in absorbency after chemical corrosion, cement composites with slag content reach the lowest values.

Contributions of Ammonia to High Concentrations of PM2.5 in an Urban Area

Atmospheric ammonia (NH3) plays a critical role in PM2.5 pollution. Data on atmospheric NH3 are scanty; thus, the role of NH3 in the formation of ammonium ions (NH4+) in various environments is understudied. Herein, we measured concentrations of NH3, PM2.5, and its water-soluble SO42−, NO3−, and NH4+ ions (SNA) at an urban site in Jeonju, South Korea from May 2019 to April 2020. During the measurement period, the average concentrations of NH3 and PM2.5 were 10.5 ± 4.8 ppb and 24.0 ± 12.8 μg/m3, respectively, and SNA amounted to 4.3 ± 3.1, 4.4 ± 4.9, and 1.6 ± 1.8 μg/m3, respectively. A three-dimensional photochemical model analysis revealed that a major portion of NH3, more than 88%, originated from Korea. The enhancement of the ammonium-to-total ratio of NH3, NHX (NHR = [NH4+]/[NH4+] + [NH3]) was observed up to ~0.61 during the increase of PM2.5 concentration (PM2.5 ≥ 25 μg/m3) under low temperature and high relative humidity conditions, particularly in winter. The PM2.5 and SNA concentrations increased exponentially as NHR increased, indicating that NH3 contributed significantly to SNA formation by gas-to-particle conversion. Our study provided experimental evidence that atmospheric NH3 in the urban area significantly contributed to SNA formation through gas-to-particle conversion during PM2.5 pollution episodes.

Modeling of U-shaped composite detectors

We have investigated the basic operation of a composite detector comprising of elements arranged in the shape of an U-shaped rectangular well. Considering an isotropic scattering of gamma-rays and partial energy absorptions in up to four detector modules, expressions for the addback factor and the peak-to-total ratio have been obtained in terms of only one probability amplitude. We have compared the performance of two U-shaped detectors having different geometries and observed negligible gain in addback due to the longer arms. For completeness, comparisons have been made with composite detectors like the two element stacked detector and the two level pyramidal detector, both being embedded inside the U-shaped detector. Our pen-on-paper approach could be used to understand the operation of modern arrays having detector elements arranged in various sophisticated ways.

Age, growth, and population structure of endemic Telestes karsticus (Actinopterygii: Cyprinidae, Leuciscinae) from Sušik Creek, Croatia

This study provides the first description of the age, growth, and population structure of the endemic karstic dace, Telestes karsticus Marčić et Mrakovčić, 2011, from Sušik Creek in Croatia. The oldest individual in the sample was a female of age 5+ years and the oldest males were 4+. Females of the karstic dace have a higher maximum standard length than males (122.0 vs. 95.1 mm, respectively). In both sexes, the most numerous length category was 41–50 mm. The most numerous age group of karstic dace was 1+, with a gradual decline in the abundance of older age groups. In larger length categories, males were fewer, while females showed a bimodal distribution with a second maximum in the length category of 81–90 mm. The total ratio of males to females in the sample was 2.8:1, in favor of males.

Age, growth, and population structure of endemic Telestes karsticus (Actinopterygii: Cyprinidae, Leuciscinae) from Sušik Creek, Croatia

This study provides the first description of the age, growth, and population structure of the endemic karstic dace, Telestes karsticus Marčić et Mrakovčić, 2011, from Sušik Creek in Croatia. The oldest individual in the sample was a female of age 5+ years and the oldest males were 4+. Females of the karstic dace have a higher maximum standard length than males (122.0 vs. 95.1 mm, respectively). In both sexes, the most numerous length category was 41–50 mm. The most numerous age group of karstic dace was 1+, with a gradual decline in the abundance of older age groups. In larger length categories, males were fewer, while females showed a bimodal distribution with a second maximum in the length category of 81–90 mm. The total ratio of males to females in the sample was 2.8:1, in favor of males.

Laboratory Investigation of Hybrid IgG4 k/λ in MuSK Positive Myasthenia Gravis

Myasthenia gravis with antibodies (Abs) against the muscle-specific tyrosine kinase (MuSK) is a rare autoimmune disorder (AD) of the neuromuscular junction (NMJ) and represents a prototype of AD with proven IgG4-mediated pathogenicity. Thanks to the mechanism of Fab-arm exchange (FAE) occurring in vivo, resulting MuSK IgG4 k/λ Abs increase their interference on NMJ and pathogenicity. The characterization of hybrid MuSK IgG4 as a biomarker for MG management is poorly investigated. Here, we evaluated total IgG4, hybrid IgG4 k/λ, and the hybrid/total ratio in 14 MuSK-MG sera in comparison with 24 from MG with Abs against acetylcholine receptor (AChR) that represents the not IgG4-mediated MG form. In both subtypes of MG, we found that the hybrid/total ratio reflects distribution reported in normal individuals; instead, when we correlated the hybrid/total ratio with specific immune-reactivity we found a positive correlation only with anti-MuSK titer, with a progressive increase of hybrid/total mean values with increasing disease severity, indirectly confirming that most part of hybrid IgG4 molecules are engaged in the anti-MuSK pathogenetic immune-reactivity. Further analysis is necessary to strengthen the significance of this less unknown biomarker, but we retain it is full of a diagnostic-prognostic powerful potential for the management of MuSK-MG.

Changes in UPR-PERK pathway and muscle hypertrophy following resistance training and creatine supplementation in rats

The unfolded protein response (UPR) plays a pivotal role in some exercise training induced-physiological adaptation. Our aim was to evaluate the changes in the protein kinase R-like endoplasmic reticulum kinase (PERK) arm of the UPR and hypertrophy signaling pathway following 8 weeks of resistance training and creatine (Cr) supplementation in rats. Thirty-two adult male Wistar rats (8 weeks old) were randomly divided into 4 groups of 8: untrained + placebo (UN + P), resistance training + placebo (RT + P), untrained + Cr (UN + Cr) and resistance training + Cr (RT + Cr). Trained animals were submitted to the ladder-climbing exercise training 5 days per week for a total of 8 weeks. Cr supplementation groups received creatine diluted with 1.5 ml of 5% dextrose orally. The flexor hallucis longus (FHL) muscle was extracted 48 hours after the last training session and used for western blotting. After training period, the RT + Cr and RT + P groups presented a significant increase in phosphorylated and phosphorylated /total ratio hypertrophy indices, phosphorylated and phosphorylated/total ratio PERK pathway proteins and other downstream proteins of the PERK cascade compared with their untrained counterparts (P < 0.05). The increase in hypertrophy indices were higher but PERK pathway proteins were lower in the RT-Cr group than in the RT + P group (P < 0.05). There was no significant difference between the untrained groups (P > 0.05). Our study suggests that resistance training in addition to Cr supplementation modifies PERK pathway response and improves skeletal muscle hypertrophy.

The interplay of systemic atrial and ventricular function in patients with transposition of the great arteries after arterial switch operation

Funding Acknowledgements Type of funding sources: None. Background/Introduction: The role of systemic atrial (LA) function and its interplay with the systemic ventricle (LV) in patients with transposition of the great arteries (TGA) after arterial switch operation (ASO) is currently not well defined. Purpose Investigate the role of LA function and its interplay with the LV. Methods Between 2007 and 2018 patients with TGA corrected by ASO and control patients of comparable age, sex, height but without known cardiovascular disease were included in this prospective single centre analysis of 3 Tesla cardiac magnetic resonance cine imaging studies of atrial and ventricular function. Additionally, in TGA patients extracellular volume fraction (ECV) was assessed by T1 mapping and global longitudinal strain (GLS) by feature tracking. Results Overall, 81 TGA (16.3 [IQR 10.5-21.2] years, 32% female) and 30 control patients (11.9 [IQR 8.7-22.5] years, 63% female) were included in the current analysis. TGA patients had smaller LA maximum volume index, and reduced total atrial and conduit volume emptying. This resulted in a reduced LA reservoir and conduit function compared to controls. In TGA, a higher LA active/conduit and active/total ratio indicated impaired passive filling of the LV. (Table 1) The median ECV was 28.3% (IQR 25.8-33.9) and the median GLS -24.2% (IQR -28.6- -20.4) in TGA patients. LA reservoir (Fig. 1A), conduit and contractile function showed a negative correlation with GLS (r=-0.470, p &lt; 0.001, r=-0.270, p = 0.022 and r=-0.257, p = 0.030, respectively). Interestingly, the LA active/conduit ratio (Fig. 1B) and the active/total ratio showed a positive correlation with ECV (r = 0.418, p = 0.002 and r = 0.339, p = 0.013, respectively). Conclusion Impaired LA function is frequent among patients with TGA following ASO. The impairment of LA function is linked to both LV dysfunction and fibrosis. Table 1 Variable TGA (n = 81) Control (n = 30) p-value LAVI max.[ml/m&sup2;] 37.8 (29.9-42.9) 42.02 (38.3-51.6) 0.002 LAVI total emptying [ml/m&sup2;] 16.8 (13.7-20.8) 24.3 (20.6-29.4) &lt;0.001 LAVI conduit emptying [ml/m&sup2;] 10.3 (8.1-13.9) 17.5 (15.2-20.8) &lt;0.001 LAVI active [ml/m&sup2;] 6.7 (4.1-8.6) 6.4 (5.0-7.9) 0.984 LA-EF-reservoir [%] 46.6 (42.0-50.5) 57.2 (51.2-60.1) &lt;0.001 LA-EF-conduit [%] 28.1 (23.4-34.3) 42.5 (35.4-45.8) &lt;0.001 LA-EF-active [%] 24.11 (17.9-29.1) 25.7 (21.5-29.7) 0.339 LA active/conduit ratio 0.60 (0.41-0.90) 0.37 (0.28-0.44) &lt;0.001 LA active/total ratio 0.38 (0.29-0.47) 0.27 (0.22-0.30) &lt;0.001 Differences in left atrial function between TGA and control patients Abstract Figure. Fig. 1A and B

Qualitative and quantitative bioanalytical methods validation of aristolochic acid DNA adducts and application in human formalin-fixed paraffin-embedded hepatocellular carcinoma tissues

Mutation signature of aristolochic acid (AA) found in urothelial or hepatocellular carcinoma causes public concern about the cancer risk of AA. In contrast, direct evidence based on the reliable bioanalytical method for the exposure of AA is still lacking and not universal. Here, we strictly complied with the qualitative and quantitative guidance for forensic toxicological analysis: In the sample preprocessing, DNA from formalin-fixed and paraffin-embedded (FFPE) tissues was digested to single nucleotide by a series of enzymes with 70% enzymatic digestion efficiency. After protein precipitation, the samples were submitted to an ABI6500+ mass spectrometer for LC-MS/MS analysis. Ion pairs 543.2/427.2 and 543.2/395.2 of dA-AAI were selected from 5 ion pairs due to their higher LC-MS/MS response. Both these ion pairs have excellent selectivity and specificity in rat liver DNA matrix, and a linear regression range from 5 pg/mL to 200 pg/mL with the best fit and determination coefficient (r) greater than 0.99. The intra and inter batch accuracy and precision of these two ion pairs are also acceptable with less than 15% variation. The total recovery for ion pair 543.2/427.2 and 543.2/395.2 of dA-AAI was 90.06% and 90.76%, respectively. Our method has a minor matrix effect and good stability under different temperature and time conditions. With signal to noise ratio ≥ 3, 2 ion pairs (< 50 % relative abundance variation), the lower limit of quantification (LLOQ) of our method is set to 5 pg/mL(∼3.6 AAI-DNA adducts per 108 DNA bases). By using this validated bioanalytical method of dA-AAI, 165 human HCC FFPE tissues were analyzed, the total ratio of samples with peak543.2/427.2 is 17.0% (28/165), with peak543.2/395.2 is 9.09% (15/165) which yields the total ratio of samples combined peak543.2/427.2 and peak543.2/395.2 is 7.27% (12/165). Two samples are higher than 5 pg/mL under the qualitative requirements. In conclusion, we first reported a fully validated methods to analyze the DNA adducts level of aristolochic acid, which could be qualitatively and quantitatively applied to the investigation of AA exposure in the human and other species.