Degree of Impurity and Carbon Contents in the Grain Size of Mg-Al Magnesium Alloys.

In this study, the tendency of having different grain structures depending on the impurity levels in AZ91 alloys was investigated. Two types of AZ91 alloys were analyzed: commercial-purity AZ91 and high-purity AZ91. The average grain size of the commercial-purity AZ91 alloy and high-purity AZ91 is 320 µm and 90 µm, respectively. Thermal analysis revealed negligible undercooling in the high-purity AZ91 alloy, while undercooling of 1.3 °C was observed in the commercial-purity AZ91 alloy. A CS analyzer was employed to precisely analyze the carbon composition of both alloys. The carbon content of the high-purity AZ91 alloy was found to be 197 ppm, while the commercial-purity AZ91 alloy contained 104 ppm, indicating a difference of approximately 2 times. The higher carbon content in the high-purity AZ91 alloy is believed to be due to the use of high-purity pure Mg in its production (the carbon content of high-purity pure Mg is 251 ppm). To simulate the vacuum distillation process commonly used in the production of high-purity Mg ingots, experiments were conducted to investigate the reaction of carbon with oxygen to produce CO and CO2. XPS analysis and simulation results for activities confirmed the formation of CO and CO2 during the vacuum distillation process. It could be speculated that the carbon sources in the high-purity Mg ingot provide Al-C particles, which act as nucleants for Mg grains in the high-purity AZ91 alloy. Thus, it can be considered the main reason that high-purity AZ91 alloys have a finer grain structure than that of commercial-purity AZ91 alloys.

Assessment of variables associated with prolonged admission duration in children with Mycoplasma pneumoniae pneumonia.

INTRODUCTION: Macrolide-resistant Mycoplasma pneumoniae (MRMP) has become prevalent in children. This study investigated the clinical and laboratory variables of MRMP and macrolide-sensitive M. pneumoniae (MSMP) and identified factors associated with prolonged hospital admission in children. METHODS: A prospective multicenter study was conducted in 1063 children <18 years old in July 2018-June 2020. The 454 had a positive M. pneumoniae polymerase chain reaction assay. RESULTS: Most subjects had MRMP (78.4%), and all mutated strains had the A2063G transition. We defined MRMP* (n = 285) as MRMP pneumonia requiring admission and MSMP* (n = 72) as MSMP pneumonia requiring admission. Patients with MRMP pneumonia were older, more likely to have segmental/lobar pneumonia, and had more febrile days than those with MSMP pneumonia. C-reactive protein (CRP), lactate dehydrogenase (LDH), and percentage neutrophils were more strongly associated with MRMP* than MSMP* groups. Percentage neutrophils, CRP, and alanine aminotransferase significantly changed between admission and follow-up measurements in patients with MRMP* (P < 0.05). The duration of admission positively correlated with the number of febrile days after initiation of antibiotic medication and laboratory variables (white blood cell count, CRP, and aspartate aminotransferase [AST]) (P < 0.05). Random forest analysis indicated that the number of febrile days after initiation of antibiotic medication, AST, and percentage neutrophils at admission was over five. CONCLUSIONS: This study indicated that children with M. pneumoniae pneumonia with a higher number of febrile days after initiation of antibiotic medication, AST, and percentage neutrophils at admission were more likely to have prolonged admission duration.

Analysis of national surveillance of respiratory pathogens for community-acquired pneumonia in children and adolescents.

BACKGROUND: Respiratory infections among children, particularly community-acquired pneumonia (CAP), is a major disease with a high frequency among outpatient and inpatient visits. The causes of CAP vary depending on individual susceptibility, the epidemiological characteristics of the community, and the season. We performed this study to establish a nationwide surveillance network system and identify the causative agents for CAP and antibiotic resistance in Korean children with CAP. METHODS: The monitoring network was composed of 28 secondary and tertiary medical institutions. Upper and lower respiratory samples were assayed using a culture or polymerase chain reaction (PCR) from August 2018 to May 2020. RESULTS: A total of 1023 cases were registered in patients with CAP, and PCR of atypical pneumonia pathogens revealed 422 cases of M. pneumoniae (41.3%). Respiratory viruses showed a positivity rate of 65.7% by multiplex PCR test, and human rhinovirus was the most common virus, with 312 cases (30.5%). Two hundred sixty four cases (25.8%) were isolated by culture, including 131 cases of S. aureus (12.8%), 92 cases of S. pneumoniae (9%), and 20 cases of H. influenzae (2%). The cultured, isolated bacteria may be colonized pathogen. The proportion of co-detection was 49.2%. The rate of antibiotic resistance showed similar results as previous reports. CONCLUSIONS: This study will identify the pathogens that cause respiratory infections and analyze the current status of antibiotic resistance to provide scientific evidence for management policies of domestic respiratory infections. Additionally, in preparation for new epidemics, including COVID-19, monitoring respiratory infections in children and adolescents has become more important, and research on this topic should be continuously conducted in the future.

Imbalance of Gut Streptococcus, Clostridium, and Akkermansia Determines the Natural Course of Atopic Dermatitis in Infant.

PURPOSE: The roles of gut microbiota on the natural course of atopic dermatitis (AD) are not yet fully understood. We investigated whether the composition and function of gut microbiota and short-chain fatty acids (SCFAs) at 6 months of age could affect the natural course of AD up to 24 months in early childhood. METHODS: Fecal samples from 132 infants were analyzed using pyrosequencing, including 84 healthy controls, 22 transient AD and 26 persistent AD subjects from the Cohort for Childhood Origin of Asthma and Allergic Diseases (COCOA) birth cohort. The functional profile of the gut microbiome was analyzed by whole-metagenome sequencing. SCFAs were measured using gas chromatography-mass spectrometry. RESULTS: Low levels of Streptococcus and high amounts of Akkermansia were evident in transient AD cases, and low Clostridium, Akkermansia and high Streptococcus were found in children with persistent AD. The relative abundance of Streptococcus positively correlated with scoring of AD (SCORAD) score, whereas that of Clostridium negatively correlated with SCORAD score. The persistent AD group showed decreased gut microbial functional genes related to oxidative phosphorylation compared with healthy controls. Butyrate and valerate levels were lower in transient AD infants compared with healthy and persistent AD infants. CONCLUSIONS: Compositions, functions and metabolites of the early gut microbiome are related to natural courses of AD in infants.

Serum vitamin D status in children and adolescence with diabetes according to season and age.

PURPOSE: It is known that children with diabetes have more severe vitamin D deficiency than healthy children. This study aimed to investigate serum vitamin D status and analyze the relationships between serum vitamin D levels and clinical parameters in children with diabetes. METHODS: We checked serum vitamin D levels of children with diabetes aged below 18 years who were treated at our Department of Pediatrics between December 2011 and February 2012 (winter) as well as between June 2012 and August 2012 (summer). We retrospectively analyzed relationships between their serum vitamin D levels and clinical parameters. RESULTS: The serum 25-hydroxyvitamin D level in children with diabetes during winter was markedly lower than during summer (10.8±5.1 ng/mL vs. 17.6±5.6 ng/mL); vitamin D deficiency was more prevalent during winter (95% vs. 62%). However, there was no difference between children with diabetes and healthy children. In children with type I diabetes mellitus, among all the clinical parameters, age had the greatest negative correlation with serum vitamin D level. CONCLUSION: In children with diabetes, serum vitamin D levels showed marked seasonal variation. However, no clear relationship was identified between vitamin D deficiency and diabetes. This was because the control group had an equally high vitamin D deficiency rate. Additional studies including other clinical parameters after vitamin D supplementation in children with diabetes should be considered.

A case of unusual visceral heterotaxy syndrome with isolated levocardia.

Situs inversus of the abdominal organs in the presence of normally placed heart on the left side of the thorax is known as situs inversus with isolated levocardia. This rare condition is commonly associated with severe congenital defects of the heart. We report a case of situs inversus with levocardia in a 19-year-old asymptomatic male patient with completely normal heart on the left chest. Spiral computed tomography of the thorax and abdomen and echocardiographic studies revealed situs inversus of abdominal organs, normal heart (levocardia), mirrored left lungs, a midline liver, a left-sided inferior vena cava connecting to the right atrium, multiple splenic masses in the abdominal right upper quadrant, and aneurysmal dilatation of a splenic artery.

Extremely increased serum carbohydrate antigen 19-9 levels caused by new or resistant infections to previous antibiotics in chronic lung diseases.

In this paper, we describe 72-year-old female patient without evidence of malignant disease presented with significantly elevated serum carbohydrate antigen (CA) 19-9 levels by respiratory infections. She was diagnosed with respiratory infections due to Mycobacterium avium complex and Pseudomonas aeruginosa. The serum CA 19-9 levels remarkably increased (1,453-5,300 U/mL; reference range, <37 U/mL) by respiratory infection and abruptly decreased (357-534 U/mL) whenever infection was controlled by specific treatments. This case suggests that serum CA 19-9 levels may be used as a diagnostic marker to indicate new or resistant infections to previous antibiotics in chronic lung diseases without significant changes in chest X-ray findings.

Gain of the EGFR gene located on 7p12 is a frequent and early event in squamous cell carcinoma of the lung.

Identification of molecular alterations in biological fluids has been proposed as a powerful tool for cancer diagnosis. The purpose of this study was to identify cells that carry chromosomal alterations indicative of malignancy-specifically, gains in the loci 5p15.2 (D5S23, D5S721), 6p11 approximately q11, 7p12 (EGFR), and 8q24.12 approximately q24.13 (MYC)-for the detection of lung cancer using induced sputum. The overall sensitivity of the multicolor fluorescence in situ hybridization (FISH) assay from 52 lung cancer patients was 71% and the specificity was 100% (15 of 15). The most frequently detected gains were at 7p12 (EGFR) in 17 of 24 completely resectable early-stage (II+IIIA) non-small cell lung cancers (NSCLC) (71%). There was a statistically significant increase in the proportion of cases with gains of EGFR in squamous cell carcinomas (SCC), compared with adenocarcinomas (AC) (82 vs. 43%, respectively; P = 0.017), and a higher average EGFR gene copy number in the SCCs than in the ACs (5.04 vs. 3.78, respectively; P = 0.013) in 41 NSCLCs. Conversely, a gain at the 6p11 approximately q11 and 8q24.12 approximately q24.13 (MYC) regions appears to have a higher frequency of gain in the ACs (71 and 86%, respectively) than in the SCCs (48 and 56%, respectively). The results of this study showed the potential utility of the LAVysion FISH assay for the detection of lung cancer by a noninvasive technique based on the analysis of genetic alterations of induced sputum. Defining abnormalities in sputum specimens as FISH aneusomy may be a possible diagnostic method for the early detection of lung cancer in screening of high-risk populations and monitoring for recurrence.

High frequency of genetic alterations in non-small cell lung cancer detected by multi-target fluorescence in situ hybridization.

Detection of genetic alterations could provide a tool as an adjuvant for the diagnosis of non-small cell lung cancer (NSCLC) and to define patients at risk for early relapse. In this study, a multi-target fluorescence in situ hybridization (FISH) assay was conducted to investigate the correlation between the alterations of chromosomes, including 5p15.2, 6p11.1-q11, 7p12, and 8q24.12-q24.13 (LaVysion Test), and clinicopathological variables, and to clarify the potential of the multi-target FISH assay in 37 NSCLC. The most notable finding was the higher frequency of a gain in chromosome 5p15.2 in early-stage (I+IIa) lung cancers. The frequency of the gain was 81.3% (16/22) in stage I tumors. The frequencies of gains in 6p11.1-q11 and 8q24.12-q24.13 were 61.5% (8/13) and 84.6% (11/13) in stage IIIa cancers, as compared with lower frequencies in stage I tumors at 25.0% and 31.3%, respectively. There was also a significant difference in the histological type. Our results suggest that a gain in 6p11.1-q11 and 8q24.12-q24.13 plays an important role in tumor progression and is associated with histological differentiation. On the other hand, gene amplification in the 5p region was one of the most consistent alterations in early-stage lung cancer, and thus a series of genes in the critical 5p15.2 region might potentially associated with the development of lung cancer.