Calibration methods and facilities for vector receivers using a laser Doppler vibrometer in the frequency range 20 Hz to 10 kHz.

Calibration methods and facilities have been employed to directly obtain sensitivities of an underwater acoustic vector receiver using two methods based on laser Doppler vibrometry. The vector receiver was first calibrated in a standing wave tube over the frequency range 20 Hz to 2 kHz, where the oscillatory velocity of the water-air interface was measured to determine the sound particle velocity at the position of vector receiver based on waveguide theory. In the frequency range 2.5-10 kHz, the vector receiver was calibrated in an anechoic vessel with dimensions of 1.2 m diameter × 1.8 m length using wideband signals, with a laser Doppler vibrometer used to detect the oscillatory motion of a plastic pellicle, which was sufficiently thin to follow the acoustic particle motion. The uncertainties of the calibration using the optical method were estimated to be 0.7-0.8 dB at 95% confidence interval. The calibration results were compared with those obtained using a reciprocity method in a 50 m × 15 m × 10 m water tank and using a comparison method in a standing wave tube, and the largest deviation did not exceed 1.0 dB over the frequency range 20 Hz to 10 kHz.

Long non­coding RNA NR2F1­AS1 facilitates the osteosarcoma cell malignant phenotype via the miR­485­5p/miR­218­5p/BIRC5 axis.

Long non­coding RNA (lncRNA) NR2F1 antisense RNA 1 (NR2F1­AS1) has been reported to be an oncogene in several cancer types, including osteosarcoma (OS). However, the underlying fundamental molecular mechanism of NR2F1­AS1 in OS remains largely unknown, which the present study aimed to elucidate. The present study demonstrated that NR2F1­AS1 expression is markedly increased in OS, and NR2F1­AS1 was shown to exert oncogenic functions in OS. Further molecular mechanistic studies revealed that microRNA (miR)­485­5p and miR­218­5p were direct targets of NR2F1­AS1. More importantly, miR­485­5p and miR­218­5p exhibited low expression levels and were negatively correlated with NR2F1­AS1 expression in OS tissues. It was then identified that baculoviral inhibitor of apoptosis repeat­containing 5 (BIRC5) was a direct target of miR­485­5p and miR­218­5p in OS cells. Furthermore, a series of experiments suggested that NR2F1­AS1 affects the proliferation, migration, invasion and apoptosis of OS cells by regulating BIRC5. Finally, it was revealed that silencing of NR2F1­AS1 repressed the OS cell malignant phenotype by binding with miR­485­5p and miR­218­5p, and then downregulating BIRC5 expression, which suggests that the NR2F1­AS1/miR­485­5p/miR­218­5p/BIRC5 axis could be a potential target for treating OS.

[Evans lateral lengthening calcaneal osteotomy in treatment of talocalcaneal coalition with hindfoot valgus deformity].

OBJECTIVE: To investigate the effectiveness of the Evans lateral lengthening calcaneal osteotomy (E-LLCOT) in treatment of talocalcaneal coalition (TCC) with hindfoot valgus deformity. METHODS: Between January 2014 and October 2017, 10 patients (13 feet) of TCC with hindfoot valgus deformities underwent E-LLCOTs. There were 6 males (8 feet) and 4 females (5 feet) with an age of 13-18 years (mean, 15.8 years). The disease duration was 10-14 months (mean, 11.5 months). The foot deformity was characterized by hindfoot valgus, forefoot abduction, and collapse of the medial arch. Pain site was the tarsal sinus in 4 feet, TCC in 5 feet, and ankle joint in 4 feet. There were tightness of the gastrocnemius in 3 cases (4 feet) and Achilles tendon in 7 cases (9 feet) on Silverskiold test. The preoperative American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score was 46.54±9.08 and visual analogue scale (VAS) score was 6.54±0.88 after walking 1 kilometer. The AOFAS ankle-hindfoot score and VAS score were adopted to evaluate the postoperative function of the foot. The talar-first metatarsal angle (T1MT), talonavicular coverage angle (TCA), talar-horizontal angle (TH), calcaneal pitch angle (CP), and heel valgus angle (HV) were measured after operation. RESULTS: All incisions healed by first intention. All patients were followed up 12-30 months (mean, 18 months). At last follow-up, the AOFAS ankle-hindfoot score and VAS score were 90.70±6.75 and 1.85±0.90, respectively, showing significant differences when compared with preoperative scores ( t=-23.380, P=0.000; t=35.218, P=0.000). X-ray films showed that the osteotomy healed at 2-4 months (mean, 3 months) after operation. At last follow-up, the T1MT, TCA, TH, and HV were significantly lower than preoperative ones ( P<0.05), and the CP was significantly higher than preoperative one ( P<0.05). During the follow-up, the pain did not relieve obviously in 1 patient (1 foot), and the cutaneous branch of the sural nerve injured in 1 patient (1 foot). CONCLUSION: For TCC with severe hindfoot valgus deformity, E-LLCOT can effectively correct deformity and relieve pain.

Gene expression profiles of disc tissues and peripheral blood mononuclear cells from patients with degenerative discs.

The objective of this study was to analyze gene expression profiles of intervertebral disc samples and peripheral blood mononuclear cells (PBMCs) from patients with degenerative discs using Agilent's Human 1A Oligo microarray. RNA samples from disc tissue and PBMCs were obtained from patients with degenerative discs and from subjects in a control group. RNA samples were reverse-transcribed into Cy5-labeled cRNA, combined with a Cy3-labeled reference and hybridized to oligonucleotide microarrays. Microarrays were scanned by Gene-Pix 4000B and data were analyzed using GenePixPro 3.0 software. The microarray data were validated in the same RNA samples by qRT-PCR analysis of selected genes. For the disc tissue, the mRNA expressions of 522 genes changed obviously in the degeneration group, accounting for approximately 2.64% of all analyzed transcripts. These included transcription-related, ion channel and transport protein, receptor, protein synthesis and modifying, growth factor, etc. For PBMCs, the expressions of 62 genes changed obviously in the patients in the degeneration group. These changes included ion channel, transport protein, transcription-related, DNA synthesis and repair, metalloprotease, immune globulin-related, growth factor-related, extracellular matrix-related, adhesion molecule, etc. Analyzed on the association of the differential expression of genes between disc tissue and PBMCs, some genes were not compatible. The course of intervertebral disc denegation is a complicated dynamic process, however, and may mainly be local pathogenesis. These findings furnish new data for the mechanistic investigation of degenerative discs.