BACKGROUND:Surface modification of orthopedic implants can reduce or prevent bacterial adhersion. Bacteriostatic and bactericidal ingredients released from special coating of metal surfaces prevent orthopedic surgery infection. OBJECTIVE:To prepare hydroxyapatite/nano-silver composite coating on the surface of medical titanium based on different preparation parameters and to observe the release properties of silver ions on the composite material surface in the simulated body fluid. METHODS:Using pulse electrochemical methods, hydroxyapatite and nano-silver were deposited in the solution containing silver, calcium and phosphate ions. Scanning electron microscopy, X-ray diffraction and energy dispersive spectroscopy were used to characterize its morphology and composition. The composite titanium materials containing 0.5, 1 mmol/L silver were immersed in the simulated body fluid, and Ag+concentration was detected by atomic absorption spectrometry at the different time points. RESULTS AND CONCLUSION:Nanoparticles were uniformly distributed in the coating which was interwoven with the nano needle-like hydroxypatite and dot-like silver particles. After high temperature processing, the coating became denser, and hydroxypatite became more crystal and silver particles exhibited no agglomeration. In the simulated body fluid, Ag+release was maximal at 1-7 days and became stable at 7-30 days which maintained an effective antimicrobial concentration. The material containing 0.5 mmol/L Ag+showed a lower amount of Ag+released than cytotoxic concentration at 30 days, but the material containing 1 mmol/L Ag+could release the total of Ag+close to the critical value of celltoxicity at 30 days. Above al , the material containing 0.5 mmol/L Ag+is more secure in the clinical application.

OBJECTIVE: To investigate the genetic characteristics and cause of death for an infant with alveolar capillary dysplasia and pulmonary vein misalignment (ACD/MPV). METHODS: An infant with ACD/MPV diagnosed at the Affiliated Maternity and Child Health Care Hospital of Nantong University in September 2022 was selected as the study subject. Clinical data of the infant were collected. Whole exome sequencing (WES) was carried out to detect genetic variants in the skin tissue, and Sanger sequencing was performed for verifying the candidate variants in the parents. Droplet digital PCR (ddPCR) was used to determine the mosaicism ratio of the variant in different germ layer-derived samples from the father. RESULTS: The infant had died within 2 days after birth due to hypoxemia and respiratory distress. WES revealed that she has harbored a c.433C>T nonsense variant in exon 1 of the FOXF1 gene, which was unreported previously. Sanger sequencing has verified the variant in the infant, with her mother's locus being the wild-type and a minor variant peak noted in her father. ddPCR indicated that the mosaic ratio of the c.433C>T variant in the father's sperm was 27.18%, with the mosaic ratios of the variant in tissues originating from the three germ layers ranging from 11% to 28%. CONCLUSION The c.433C>T variant derived from the paternal germline and somatic mosaicism of the FOXF1 gene had probably predisposed to the neonatal death of this infant. ddPCR is an effective method for detecting mosaic variants.
Female ; Humans ; Pregnancy ; Child ; Infant ; Infant, Newborn ; Male ; Semen ; Infant Death ; Exons ; Mosaicism ; Forkhead Transcription Factors/genetics*