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ZrC-SiC coating on Cf/ZrC-SiC composite was fabricated via in situ reaction using zirconium powder, silicon powder, and phenolic resin as raw materials. The coated composites exhibited excellent oxidation performance. In particular, the coating closely adhered onto the composites, and had a uniform thickness of approximately 90 μm and did not show significant cracking. Even after 30 min of oxidation at 1700 °C in a muffle furnace, the coating thickness of 90 μm remained. Meanwhile, the density of the coating was increased with oxidation because the pores on the surface were filled with the mixtures of ZrC, ZrO2, and SiC. Three distinct layers were formed in the composite, namely, surface oxide, intermediate and unoxidised layers. Therefore, the coating effectively protected the composites from oxidation. [ABSTRACT FROM AUTHOR]

Background : The biochemical and genetic characteristics of four very-long-chain acyl-coenzyme A dehydrogenase deficiency (VLCADD) patients, clarifying their pathogenic genetic factors and evaluating the application value of genetic diagnosis in the early diagnosis of VLCADD, are reported and discussed in this article. Methods : Patients underwent blood tandem mass spectrometry (MS/MS), urine gas chromatography (GC/MS), and high-throughput sequencing technology. New variants were analyzed for pathogenicity using bioinformatics software. Swiss-PdbViewer software was used to predict the effect of variants on the structure of the very-long-chain acyl-CoA dehydrogenase (VLCAD) protein. Result : A total of four VLCADD patients were diagnosed. They revealed elevated levels of C14, C14:1, C14:2, C14:1/C2, C14:1/C10, and C14:1/C12:1. Two patients were early-onset neonatal cases and died during infancy and the neonatal period, respectively. Seven kinds of variants were detected, including four novel variants. Bioinformatics software revealed that the variants were harmful, and the Swiss-PdbViewer results suggest that variation affects protein conformation. Conclusion : This study identified four novel ACADVL gene variants. These findings contribute to the understanding of the genetic basis and pathogenesis of VLCADD. Meanwhile, the study enriches the genetic mutation spectrum and the correlation between genotypes and phenotypes of VLCADD, indicating that genetic diagnosis plays an essential role in the early diagnosis and treatment of VLCADD., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Li, Tang, Zhao, Gong, Yang, Wang, Yang and Kong.)

Objective: To investigate the clinical characteristics of infants with short-chain acyl-CoA dehydrogenase deficiency (SCADD) and related gene mutations in Beijing., Methods: The acylcarnitine levels in the blood samples of 100 603 neonates in Beijing during August 2014 and March 2022 were measured by tandem mass spectrometry (MS/MS). The suspected SCADD neonates were rechecked by MS/MS, urine gas chromatography-mass spectrometry (GC/MS) and next-generation sequencing (NGS) for diagnosis. The clinical, biochemical and gene mutation characteristics of infants with SCADD were analyzed; the growth and intellectual development of these patients were observed regularly., Results: Among 100 603 live births, the elevated C4 concentration or elevated C4/C3 ratio were detected in the initial screening from 196 neonates, and 131 were recalled. Five cases of SCADD were diagnosed with an incidence rate of 4.97/100 000 (1/20 121). There was no significant abnormality in clinical manifestations, however, the blood butyrylcarnitine (C4) level and the ratio of C4 to propionylcarnitine (C3) were raised in all diagnosed cases. Urinary organic acids were analyzed in 4 cases, all of whom had increased ethyl malonate acid levels. Seven mutations were detected in the ACADS gene, all of which were known missense mutations. One patient had homozygous mutation, and the others showed compound heterozygous mutations. No clinical symptoms were observed, and the physical and intellectual development was normal in all patients at a median age of 33 (4-40) months during follow-up., Conclusions: The incidence rate of SCADD was 1/20 121 in Beijing. Neonates with early diagnosis and without clinical symptoms usually have good prognosis.

Objective: 3-Methylcrotonyl-coenzyme A carboxylase deficiency (MCCD) is an autosomal recessive inborn error of leucine catabolism. The cases suspected as MCCD detected by neonatal screening are not rare. The aim of the study was to investigate the clinical outcomes in cases suspected as MCCD by neonatal screening. The second aim was to investigate the mutation spectrum of MCC gene in Chinese population and hotspot mutation., Method: Forty-two cases (male 33, female 9) , who had higher blood 3-hydroxy-isovalerylcarnitine (C5-OH) levels(cut-off <0.6 µmol/L) detected by neonatal screening using MS/MS, were recruited to this study during Sept.2011 to Mar.2013. The C5-OH concentrations were [0.84 (0.61-20.15) µmol/L] in 42 cases at the screening recall. Five cases were firstly diagnosed as maternal MCCD, 6 cases as benign MCCD and 31 cases were suspected as MCCD. To follow up the height, weight, mental development, blood C5-OH concentrations and urinary 3-methylcrotonyl-glycine (3-MCG) and 3-hydroxy isovalerate (3-HIVA) in order to investigate the clinical outcome. The MCCC1 and MCCC2 gene mutation were analyzed for some cases. The novel gene variants were evaluated, and the influence of novel missense variants on the protein structure and function were predicted by PolyPhen-2, SIFT, UniProt and PDB software., Result: (1) Forty-two cases had no symptoms, their physical and mental development were normal in the last visit at the median ages of 29 months, the oldest age of follow up was nearly 9 years. (2) Gene mutation analysis was performed for 29 cases with informed consent signed by parents.Fourteen different mutations were identified in 19 cases. The mutations in MCCC1 gene accounted for 86%, the most common mutation was c.ins1680A, (accounted for 40%). Nine kinds of novel variant were detected including 211AG>CC/p.Q74P, c.295G>A/p.G99S, c.764A>C/p.H255P, c.964G>A/p. E322K, c.1331G>A/p.R444H, c.1124delT, c.39&#95;58del20, c.1518delG, c.639+2T>A.Other 3 kinds of mutation in MCCC1 gene and 2 kinds of mutation in MCCC2 gene have been reported previously; the amino acid of mutant positions of five kinds of novel missense variant are almost highly conserved. These missense variants were predicted to cause change of human MCC protein side chain structure by changing hydrogen bonding, size of amino acid residue and electric charge, and predicted to damage the protein function possibly according to PolyPhen-2 and PDB analysis. So these novel variants may be disease-causing mutations. No mutation were detected in 10 cases. (3) Blood concentrations of C5-OH when screening, recall and end of follow-up in maternal MCCD was 3.50 (1.63-11.43), 1.84 (1.00-9.30), 0.27 (0.26-5.81) µmol/L. There was a significant downward trend.In contrast, benign MCCD group was 8.20 (3.60-9.60), 9.67 (3.88-20.15), 23.0 (5.87-49.10) µmol/L.It showed a rising trend. Children's urinary 3-MCG of benign MCCD group was found abnormally elevated in 4 cases (100%) when they were recalled., Conclusion: A certain number of cases with MCCD or suspected as MCCD in this study had no symptoms and normal physical and mental development after follow-up to oldest age of nearly 9 years. The mutation in MCCC1 gene is common, nine novel mutations were found, c.ins1680A may be a hotspot mutation in Chinese population. The urinary GC/MS analysis and blood MS/MS analysis for mother should be routinely performed for all cases with high blood C5-OH level detected by neonatal screening.