Krylov complexity in the IP matrix model II

We continue the analysis of the Krylov complexity in the IP matrix model. In a previous paper, for a fundamental operator, it was shown that at zero temperature, the Krylov complexity oscillates and does not grow, but in the infinite temperature limit, the Krylov complexity grows exponentially in time as $\sim \exp\left( {\mathcal{O}\left( {\sqrt{t}}\right)} \right)$. We study how the Krylov complexity changes from a zero-temperature oscillation to an infinite-temperature exponential growth. At low temperatures, the spectral density is approximated as collections of infinite Wigner semicircles. We showed that this infinite collection of branch cuts yields linear growth to the Lanczos coefficients and gives exponential growth of the Krylov complexity. Thus the IP model for any nonzero temperature shows exponential growth for the Krylov complexity even though the Green function decays by a power law in time. We also study the Lanczos coefficients and the Krylov complexity in the IOP matrix model taking into account the $1/N^2$ corrections. There, the Lanczos coefficients are constants and the Krylov complexity does not grow exponentially as expected.Comment: 35 pages, 18 figure

NoisyILRMA: Diffuse-Noise-Aware Independent Low-Rank Matrix Analysis for Fast Blind Source Extraction

In this paper, we address the multichannel blind source extraction (BSE) of a single source in diffuse noise environments. To solve this problem even faster than by fast multichannel nonnegative matrix factorization (FastMNMF) and its variant, we propose a BSE method called NoisyILRMA, which is a modification of independent low-rank matrix analysis (ILRMA) to account for diffuse noise. NoisyILRMA can achieve considerably fast BSE by incorporating an algorithm developed for independent vector extraction. In addition, to improve the BSE performance of NoisyILRMA, we propose a mechanism to switch the source model with ILRMA-like nonnegative matrix factorization to a more expressive source model during optimization. In the experiment, we show that NoisyILRMA runs faster than a FastMNMF algorithm while maintaining the BSE performance. We also confirm that the switching mechanism improves the BSE performance of NoisyILRMA.Comment: 5 pages, 3 figures, accepted for European Signal Processing Conference 2023 (EUSIPCO 2023

Biomechanical Study of Cervical Posterior Decompression

Study Design Biomechanical study. Purpose We examined the dynamic characteristics of different operative procedures using three-dimensional finite-element models. Overview of Literature Cervical laminoplasty is often selected for patients requiring multilevel spinal decompression. Many laminoplasty techniques have been developed and are continually being improved. Methods Images were extracted for the two intervertebral joints between C3 and C5 in domestic rabbits. The following models were created: preoperative, laminectomy, Z-plasty, open door laminoplasty, French open door laminoplasty, en-bloc laminoplasty, and double-door laminoplasty. The loads required for sagittal rotation of 2.5°, 5°, and 7.5° were measured in vitro and respectively placed at the bottom of the C5 model. Displacement of the plate in the X, Y, and Z coordinates was measured and the rotational angles of the plate were determined. Results The sagittal rotation angle was greater in the laminectomy model than in the preoperative model, but was almost the same in the preoperative and Z-plasty models. Compared with the preoperative model, sagittal rotation angles were smaller in the French open door, open door, en-bloc, and double-door laminoplasty models. Conclusions Laminectomy and various types of laminoplasty are associated with different mechanical features, such as stability and mobility, allowing for selection of the most appropriate surgical procedure for each case

Case report: Novel NIPBL-BEND2 fusion gene identified in osteoblastoma-like phosphaturic mesenchymal tumor of the fibula

Phosphaturic mesenchymal tumor (PMT) is a rare tumor that secretes fibroblast growth factor 23 (FGF23) and causes hypophosphatemia and tumor-induced osteomalacia (TIO). Fusion genes FN1-FGFR1 and FN1-FGF1 have been detected in some PMTs, but the pathogenesis of PMTs without these fusion genes remains unclear. Here, we report a 12-year-old boy with persistent muscle weakness and gait disturbance. Roentgenographic examination revealed a radiolucent lesion with endosteal scalloping in the left fibula, while his serum level of FGF23 was markedly increased. Combined with simple X-ray findings of other body parts, we suspected that TIO was caused by PMT, and resected the tumor. After resection, the serum level of FGF23 started to decrease immediately and normalized within 3 hours after resection, with this being earlier than normalization of the serum phosphorus level. In RNA sequencing, FN1-FGFR1 and FN1-FGF1 were not detected, but a novel NIPBL-BEND2 fusion gene was identified. When we forcedly expressed this fusion gene in HEK293T cells and MG63 cells, cell proliferation was enhanced in both cell lines. Furthermore, Gene set enrichment analysis of HEK293T cells showed significant upregulation of MYC-target genes. Our results suggest that this novel NIPBL-BEND2 fusion gene promotes cell proliferation possibly via the MYC pathway and might be one of the etiologies of PMTs other than FN1-FGFR1 or FN1-FGF1

Genome-wide meta-analysis identifies multiple novel loci associated with serum uric acid levels in Japanese individuals

Gout is a common arthritis caused by elevated serum uric acid (SUA) levels. Here we investigated loci influencing SUA in a genome-wide meta-analysis with 121,745 Japanese subjects. We identified 8948 variants at 36 genomic loci (P<5 × 10–8) including eight novel loci. Of these, missense variants of SESN2 and PNPLA3 were predicted to be damaging to the function of these proteins; another five loci—TMEM18, TM4SF4, MXD3-LMAN2, PSORS1C1-PSORS1C2, and HNF4A—are related to cell metabolism, proliferation, or oxidative stress; and the remaining locus, LINC01578, is unknown. We also identified 132 correlated genes whose expression levels are associated with SUA-increasing alleles. These genes are enriched for the UniProt transport term, suggesting the importance of transport-related genes in SUA regulation. Furthermore, trans-ethnic meta-analysis across our own meta-analysis and the Global Urate Genetics Consortium has revealed 15 more novel loci associated with SUA. Our findings provide insight into the pathogenesis, treatment, and prevention of hyperuricemia/gout

ABCA1 gene-physical activity interaction for HDL-C

Few studies have investigated the interactions between HDL-C-related SNPs identified by genome-wide association (GWA) study and physical activity (PA) on HDL-C. First, we conducted a sex-stratified GWA study in a discovery sample (2,231 men and 2,431 women) and replication sample (2,599 men and 3,109 women) to identify SNPs influencing log-transformed HDL-C in Japanese participants in the baseline survey of the Japan Multi-Institutional Collaborative Cohort Study. We also replicated previously reported HDL-C-related SNPs in a combined (discovery plus replication) sample (4,830 men and 5,540 women). We then analyzed the interactions of the HDL-C-related SNPs with PA on HDL-C. The sex-stratified GWA analyses identified 11 and 10 HDL-C-related SNPs in men and women as targets for an interaction analysis. Among these, only one interaction of ABCA1 rs1883025 with PA was statistically significant in men, after Bonferroni correction [P-interaction = 0.001 (α = 0.05/21 = 0.002)]. The per-major-allele (C allele) increase in log-transformed HDL-C was lost in men with low PA (β = 0.008) compared with those with medium (β = 0.032) or high PA (β = 0.034). These findings suggest that the benefit of carrying a C allele of ABCA1 rs1883025 on enhancing HDL-C may be attenuated in inactive men

Complications Associated With Spine Surgery in Patients Aged 80 Years or Older: Japan Association of Spine Surgeons with Ambition (JASA) Multicenter Study

Study Design:Retrospective study of registry data.Objectives:Aging of society and recent advances in surgical techniques and general anesthesia have increased the demand for spinal surgery in elderly patients. Many complications have been described in elderly patients, but a multicenter study of perioperative complications in spinal surgery in patients aged 80 years or older has not been reported. Therefore, the goal of the study was to analyze complications associated with spine surgery in patients aged 80 years or older with cervical, thoracic, or lumbar lesions.Methods:A multicenter study was performed in patients aged 80 years or older who underwent 262 spinal surgeries at 35 facilities. The frequency and severity of complications were examined for perioperative complications, including intraoperative and postoperative complications, and for major postoperative complications that were potentially life threatening, required reoperation in the perioperative period, or left a permanent injury.Results:Perioperative complications occurred in 75 of the 262 surgeries (29%) and 33 were major complications (13%). In multivariate logistic regression, age over 85 years (hazard ratio [HR] = 1.007, P = 0.025) and estimated blood loss ≥500 g (HR = 3.076, P = .004) were significantly associated with perioperative complications, and an operative time ≥180 min (HR = 2.78, P = .007) was significantly associated with major complications.Conclusions:Elderly patients aged 80 years or older with comorbidities are at higher risk for complications. Increased surgical invasion, and particularly a long operative time, can cause serious complications that may be life threatening. Therefore, careful decisions are required with regard to the surgical indication and procedure in elderly patients