Effect of the Rolling Process on the Properties of the Mg/Al Bimetallic Bars Obtained by the Explosive Welding Method.

This study aims to analyze the influence of the rolling process on the microstructure and corrosion properties of the Mg/Al bimetallic bars obtained by the explosive welding method. The bars investigated were rolled using two different types of rolling: classical rolling (Variant I) and modified rolling (Variant II). Two different temperatures (300 °C and 400 °C) for each of the variables were applied as well. In this study, rods with an aluminum plating layer constituting 16.8% of the cross-sectional area and an average thickness of about 0.93 mm were investigated. Based on the revealed results, it was found that after the rolling process, the material shows clearly lower values of both icor and current in the passive range. In the joint zone of Mg/Al rods rolled at 400 °C, Al3Mg2 and Mg17Al12 intermetallic phases are distinguished, localized next to the Mg core, and characterized by columnar, coarser grains. In the transition zone closer to the Al layer, only the Al3Mg2 phase is revealed, characterized by a refined, small grain size.

Ukrainian War Refugee Children With Particularly Severe Viral Infections: A Case Series Report.

The humanitarian crisis in Ukraine in 2022 led to a massive migration of refugees to Poland. Immigrant children, living in overcrowded humanitarian hubs, were exposed to multiple stressful factors likely affecting their immune systems. This case series study aimed to describe a particularly severe course of common viral infections, in Ukrainian refugee children. We present 2 case series of Ukrainian refugee children: 5 hospitalized due to either adenovirus (AdV) and 8 with rotavirus (RV) infection, admitted within 3 months in each case series, recruited retrospectively. Most patients lived in humanitarian hubs and were neglected on admission (dehydrated, with poor hygiene and anxious). All RV infection cases had symptoms of severe gastroenteritis requiring intravenous rehydration. Metabolic acidosis was present in 6 children, and hypoglycemia in 4 participants. None of them were vaccinated against RV. All children with AdV infection had prolonged fever, dyspnea requiring oxygen therapy and hyperinflammation. In 2 AdV infection cases with no clinical improvement and increasing inflammatory markers, intravenous immunoglobulins and glucocorticosteroids were used. The combination of stressful factors and living in overcrowded hubs during the high prevalence of viral infections led to a particularly severe course of viral infections in Ukrainian refugee children.

Microstructure and Mechanical Properties of the Joints from Coarse- and Ultrafine-Grained Al-Mg-Si Alloy Obtained via Friction Stir Welding.

In the present study, the welding of coarse- (CG) and ultrafine-grained (UFG) Al-Mg-Si alloy using friction stir welding (FSW) was attempted. The purpose of welding the UFG material was to check the possibility of applying FSW to materials with a thermally unstable microstructure, which is achieved by severe plastic deformation. This group of materials has significant potential due to the enhanced mechanical properties as a result of the elevated number of structural defects. The CG sample was also examined in order to assess whether there is an influence of the base material microstructure on the weld microstructure and properties. To refine the microstructure, incremental equal channel angular pressing was used. Plastic deformation resulted in grain refinement from 23 µm to 1.5 µm. It caused an increase in the microhardness from 105 HV0.1 to 125 HV0.1 and the tensile strength from 320 MPa to 394 MPa. Similar welds obtained using an FSW method exhibited good quality and grain size in a stir zone of 5 µm. For both welds, a decrease in the microhardness occurred in the stir zone. However, for the weld of UFG Al-Mg-Si, the microhardness distribution was homogeneous, while for the weld of the CG, it was inhomogeneous, which was caused by different characteristics of the second-phase precipitates. The tensile strength of the welds was lowered and equaled 269 MPa and 220 MPa for the CG and UFG welds, respectively.

Comparison of clinical severity and epidemiological spectrum between coronavirus disease 2019 and influenza in children.

Data on the novel coronavirus disease 2019 (COVID-19) in children are limited, and studies from Europe are scarce. We analyzed the clinical severity and epidemiologic aspects of COVID-19 in consecutive children aged 0-18 years, referred with a suspicion of COVID-19 between February 1, and April 15, 2020. RT-PCR on a nasopharyngeal swab was used to confirm COVID-19. 319 children met the criteria of a suspected case. COVID-19 was diagnosed in 15/319 (4.7%) patients (8 male; mean age 10.5 years). All of them had household contact with an infected relative. Five (33.3%) patients were asymptomatic. In 9/15 (60.0%) children, the course of the disease was mild, and in 1/15 (6.7%), it was moderate, with the following symptoms: fever (46.7%), cough (40%), diarrhea (20%), vomiting (13.3%), rhinitis (6.7%), and shortness of breath (6.7%). In the COVID-19-negative patients, other infections were confirmed, including influenza in 32/319 (10%). The clinical course of COVID-19 and influenza differed significantly based on the clinical presentation. In conclusion, the clinical course of COVID-19 in children is usually mild or asymptomatic. In children suspected of having COVID-19, other infections should not be overlooked. The main risk factor for COVID-19 in children is household contact with an infected relative.

Liver Fibrosis Evaluated With Transient Elastography in 35 Children With Chronic Hepatitis C Virus Infection.

BACKGROUND: The aim of this prospective study was to analyze liver fibrosis in teenagers with chronic hepatitis C (CHC) using noninvasive methods. METHODS: Thirty-five patients with CHC, 12-17 years of age (mean 14.2 ± 1.8 years; 22/35, 63% male) were included. Most of them (29/35, 83%) were infected vertically, 21/35 (60%) were treatment-naive, 30/35 (86%) were infected with genotype 1 and 5/35 (14%) were infected with genotype 4 HCV. In all patients, evaluation of liver fibrosis was performed using transient elastography (TE) and measurement of the following serum biomarkers: aspartate transaminase-to-platelet ratio index (APRI) and Fibrosis-4 index (FIB-4). Using liver stiffness measurement (LSM) results as a reference, the diagnostic performance of APRI and FIB-4 was assessed by calculating area under the receiver operating characteristics curve. RESULTS: Transient elastography results revealed no or mild fibrosis (F0/1 in METAVIR scale) in 31/35 (89%) patients. In 4/35 (11%) patients, significant fibrosis was observed (F ≥ 2), including 3/35 (9%) with cirrhosis (F4). The median APRI was 0.32, and the median FIB-4 was 0.32. LSM was associated with both APRI and FIB-4 [r = 0.61, 95% confidence interval (CI) 0.35-0.79, P = 0.0001; and r = 0.60, 95% CI 0.32-0.78, P = 0.0002, respectively]. For the diagnosis of significant fibrosis, the area under the receiver operating characteristics (95% CI) for both APRI and FIB-4 was 0.855 (0.695-0.951). APRI, with a cutoff >0.374, predicted significant fibrosis, with 100% sensitivity and 67.7% specificity, whereas FIB-4, with a cutoff >0.402, predicted significant fibrosis, with 75.0% sensitivity and 90.3% specificity. CONCLUSIONS: Significant fibrosis, including cirrhosis, may occur in teenagers with CHC. Serum biomarkers (APRI, FIB-4) correlate positively with LSM.

Somatotype variables related to strength and power output in male basketball players.

PURPOSE: The purpose of this study was to investigate the relationship between somatotype, muscular strength, power output measured in maximal cycle ergometer exercise bouts, and maximal power output and height of rise of the body mass centre (jump height) measured in akimbo counter movement jump (ACMJ), counter movement jump (CMJ) and spike jump (SPJ), in male basketball players. METHODS: Thirteen male basketball players (second division, age 19.4 ± 0.8 years, body height 192.9 ± 5.6 cm, body mass 88.8 ± 8.6 kg, training experience 9.3 ± 0.8 years) participated in the study. Somatotype was determined using the Heath-Carter method. Maximal joint torques were measured under static conditions. Power output was measured in 2 maximal cycle ergometer exercise bouts, 10 seconds each, with increasing external loads equal to 7.5 and 10.0% of the body weight (BW). All jump trials (ACMJ, CMJ and SPJ) were performed on a force plate. RESULTS: The mean somatotype of basketball players amounted to: 2.8-4.2-3.2. The sum of the joint torques for left and right lower extremities (0.613), trunk (0.631) and all six measured muscle groups (0.647) were significantly correlated (p < 0.05) with the mesomorphic component. Endomorphic, mesomorphic and ectomorphic components were correlated insignificantly with values of maximal power and height of jump during ACMJ, CMJ and SPJ trials. The power output measured in maximal cycle ergometer exercise bouts with increasing external loads was significantly correlated (p < 0.05) with mesomorphy and ectomorphy. CONCLUSION: It can be assumed that basketball players' anthropometric characteristics can influence their level of performance but it is not a decisive factor.